Endocrine System10/24/13 6:47 PM38/31Kingdom Animalia- man is part of animal kingdom- top groupingAnatomy: study of the parts of the body and how they relate to each other Gross/Macroscopic: study of large body parts visible to naked eyeRegional: all structures in particular region of bodySystematic: structure of the body are studied by systemsMicroscopic: very small structures that are viewed by microscopes not the naked eyeCytology: cells viewedHistology: tissues viewedDevelopmental: structural changes that occur in body throughout the life spanNeed all organ systems working in unisonCell form communitiesTissues are made up of group of similar cells to perform specific roleComparative Anatomy: compare different structures /organs of the bodyAnatomy Study success1. observation2. manipulation3. master terms

Anatomical position1. body erect2. feet slight apart3. palms face forward4. thumbs away from body

Planes/SectionsFrontal: vertical cut= divides body into anterior and posteriorSagittal: vertical cut=divides body into left/right partsMidsagittal: cut exactly in mid line that divides body into EQUAL left/right parts

Anatomy 9/2

-body has to be in anatomical position for dissection -2 cavities in body trunk: dorsal and ventral cavities -see these two cavities by frontal cut-dorsal: spinal cord and brain-ventral: larger cavity and subdivided into superior thoracic cavity and inferior abdominopelvic cavity -ventral is divided by diaphragm -Thoracic cavity: contains heart and lungs-Abdominal cavity: contains digestive organs-ventral cavity surrounded by serous membrane -each organ has its own compartment, which prevents spread of infection-Compartmentalization allows each organ in the body cavity to be surrounded by its own membrane -organs in dorsal cavity are surrounded by membranes called meninges (inflammation of meninges= meningitis) -dorsal cavity is composed of the cranial cavity= houses the brain; and the vertebral cavity= houses the spinal cord

-Ventral Cavity1. Superior Thoracic Cavity2. Inferior Abdominopelvic Cavity -these are divided by the diaphragm -membranes called serous membranes surround organs in the ventral body cavity

Advantages of Compartmentalization1. prevents the spread of infection from one organ to another in same body cavity2. prevents interference of the functioning of each organ by neighboring organs in the same body cavity

9 division of abdominopelvic cavity, but a simpler way is the 4 quadrants (right/left upper and lower)

Abdominal cavity and pelvic cavity blend in so you cant divide them

Physiology: study of the function of the body parts-structure defines function1. Systemic physiology: study of the function of the systems body

11 organ systems in body and all 11 organ systems work together to sustain the human body, referred to as HOMEOSTASIS

if one organ system isnt working it is homeostatic imbalanceif one system fails and not repaired other systems will fall apart

11 systems: integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, reproductive

talk about endocrine system when there in a body imbalance

Levels of structural organization1. Chemical- atoms combine to form molecules2. Cellular- cells made up of molecules3. Tissue- tissues made up of similar types of cells4.. Organ- organs made up of different types of tissues5. Organ system- consists of different organs that work together closely6. Organismal- organisms made up of many systems

HOMEOSTASIS: balance in the body-established by 2 regulatory organ systems: nervous and endocrine -nervous system: fast action, short-lived and localized -endocrine system: generally slow action, long lasting and global (release hormones in the blood stream)Homeostasis imbalance=DISEASES-a quick adjustment use the nervous system

Chapter 2: Chemical Level (lowest level)-looking at structural organization in the human body (6 structural levels)-Chemical level is the LOWEST -means were looking at the biochemical reactions occurring in the body -these chemical reactions are what we refer to as physiological processes necessary to sustain life

-matter: anything that occupies space and has mass; composed of elements-atoms=building blocks of all matter-112 elements; most important: CARBON, NITROGEN, OXYGEN, HYDROGEN

Structure of an atom:1. protons: positively charged- in the nucleus and is referred to as ATOMIC #2. neutrons: neutral in nucleus therefore nucleus is POSITIVE3. elections: negatively charged in outer shells

9/7electrons are located/arranged in the orbits/shells in a specific mannerfirst shell: max 2 electronssecond shell: max 8 electronsthird shell: max 18 electrons however stable with 8 electronsoutermost shell is VALENCE shellif valence shell does not contain max number of electrons, the atom is UNSTABLE and therefore chemical reactiveatoms are not happy unless shells are fullachieve stability in 2 wayslose electrons or gain electronsinert elements: atoms with valence shells complete and therefore chemically inert, unreactiveex: atom with 10 electrons, 2 in first and 8 in 2nd so therefore stablenoble gaseschemically-reactive elements: atoms in the elements that have incomplete valence shells and therefore unstable and chemically reactiveachieve stability thorough forming CHEMICAL BONDS with other atoms using their valence electrons- results in formation of molecules and compounds3 types of chemical bondscovalent bonds: electrons shared between atoms to attain stability nonpolar: shared equally ex: CO2polar: UNEQUAL; one atom pulls the shared electrons closer to itself= ELECTRONEGATIVE and the other atom is ELECTROPOSITIVEoxygen: electronegative; hydrogen=electropositiveionic bonds: complete transfer of electrons ex: Na+ Cl-no longer an atom if gain/lose electrongaining/losing takes energyso is it easier to lose 7 or gain 1 to attain stability?Atom losing electron is CATION (positive) and atom accepting electron is ANION (negative)Hydrogen bonds: wear bond between hydrogen atoms (electropositive) and electronegative ionsPolar covalent compound Hydrogen bond= weakest; ionic b/c complete transfer; polar covalent b/c unequal share; nonpolar covalent b/c equal sharing

Inorganic and Organic CompoundsInorganic: DONT contain carbon (except carbon monoxide and carbon dioxide)= water, acids, bases, saltsOrganic: contain carbon that are covalently bondedEx: carbs, lipids, proteins, nucleic acids

Water- polar covalent moleculeMost abundant compound in body- 70% of the volume of cellsKnown as universal solvent; involved in all biochemical reactions occurring in bodyHigh heat capacity-absorbs body heatHigh heat of vaporization: water evaporates from body using large amounts of heat-cools the bodyFor cushioning around body organs such as the brain

Acids and BasesAcids: substances that release hydrogen ions (H+)= protons. Hence, acids are also known as proton donors ex: HCL, H2CO3Negative log of the H+ concentration= pHThe H+ concentration is inversely proportional to the pH; the higher the H+ concentration, the lower the pH and vice versaBlood pH is strictly maintained between 7.35-7.45 (slightly above neutral pH)- the optimum pH for the actions of enzymes involved in the physiological processesHigh pH=low acidity, vice versaBases- substances that accept H+, proton acceptorsEx: HCO3-, NaOHAcid-base balance is regulated by buffers-chemicals that resist abrupt changes in pH by binding H+ when the pH falls and by releasing H+ when the pH rises

Salts are ionic compounds that dissociate completely in water to give cations and anions

Organic CompoundsCarbs: monosaccharide, disaccharides, polylook at PowerPointHuge role in digestionLipids: neutral fats (triglycerides) phospholipids, steroids,Proteins: fibrous and globular proteinsNucleic acids: DNA and RNA

Carbohydrates- hydrated carbonsMonosaccharide=general formula sweet/soluble in waterMonomers of carbohydratesHexose (CH2O)6- glucose, fructose, galactosePentose=(CH2O)5- deoxyribose, riboseDisaccharides- compose of 2 hexose sugars; sweet and soluble in waterMaltose (grain sugar)- glucose and glucoseSucrose (table sugar)- glucose and fructoseLactose (milk sugar)- glucose and galactoseIf lactose intolerant dont have lactase to break down lactose into the 2 monosaccharidesPolysacchardies are broken up into disaccharides for digestionLong chains of glucoseStorage form of glucosestarch in plant cellsGLYCOGEN in animal cellsInsoluble in water and not sweet

LipidsHydrophobic (insoluble in water)4 typesNeutral fats=triglycerideMost abundant form of fat in human dietKnown as Fats when solid and oils when liquids2 types: saturated and unsaturatedunsaturated: at least one double covalent bond in the carbon chain; liquid at room temp; plant sourcessaturated: single covalent bonds exist between all the carbons in the chain; solid at room temp; animal sources-butterSaturated fats increase LDL which increases strokes and heart attacksBetter to have unsaturated than saturated3 types of LipoproteinsvLDL= very low density lipoproteinLDL= low density lipoprotein= BAD CHOLESTEROLHigh content of cholesterolHDL= high density lipoproteins=GOODCarry cholesterol from blood to liver where it will be eliminated from the bodyNeed cholesterol Maintain the structure of the plasma membraneSynthesis of the steroid hormones: need these to establish homeostasis and reproductionThe human body can synthesize 85% of the cholesterol neededHave to supplement via the diet 15%Any excess cholesterol in the body carried by LDL will cause plagues to deposit in the internal walls of the blood vessels: ATHEROSCLEROTIC plagues= condition of ATHEROSCLEROSISATHEROSCLEROSIS can lead to hypertension---chronic increase in blood pressureHypertension will lead to congestive heart failureAtherosclerosis plaque formation is smaller blood vessels-smallest blood vessels in the human body1. Cerebral blood vessels2. Coronary blood vesselsPlaque formation in these blood vessels can cause occlusion of these blood vessels= no blood flow; tissues served by the occluded vessels dieOcclusion of cerebral blood vessels= ISCHEMIC STROKES= brain attackOcclusion of coronary blood vessels= MYOCARDIAL INFARCTION= heart attackThis all explains why LDL is referred to as the bad cholesterol HDL: good cholesterolCholesterol transported by HDL to the liverCholesterol is degraded and eliminated from the bodyLowers cholesterol level in the blood vesselsDecreases chances of developing atherosclerotic plaguesPhospholipids: polar head and 2 nonpolar tailsPolar heads= hydrophilic, tails=hydrophobicMake up the membrane: non polar tails form the core of the plasma membraneForm micelles to transport hydrophobic neutral fats in the aqueous environment in the intestinal lumen Steroids: derived from cholesterolEicosanoids-derived from arachidonic acids

ProteinsBuilding blocks of proteins are AMINO ACIDSEach amino acid has an AMINO terminal that can act as a base and a CARBOXYL terminal that can act as an acidAmino acids are amphoteric molecules can act as acids and bases20 naturally occurring amino acidsessential amino acids: must be ingested in the dietnon-essential amino acids: the cells are capable of synthesizing these amino acids via a process known as TRANSAMINATION use amino acids in translation to make proteins4 structure levelsprimary structure: linear polypeptide chain indicate the type and position of amino acidsecondary structure: 2 typesalpha HELIX coiled: coiled polypeptide chainbeta PLEATED sheet: polypeptide chains linked side by sidetertiary structure: secondary structure folded upon themselves to give a compact, globular molecule---3 dimensionalQuaternary structure: 2 or more polypeptide chains are held together by disulfide bonds Ex: hemoglobin; insulin 2 Classes of ProteinsFibrous proteinsExtended/ strand-likeInsoluble in waterForm the framework of all cells: structural proteinsProvide mechanical and support and tensile strength as the main building material in the bodyDont denatureEx: collagenGlobular ProteinsCompact/ball-likeSoluble in water, sensitive to pH and temp changeChemically active- mediate all biochemical reactions occurring in the bodyFunctional proteinsEx: enzymesAre denatured (irreversibly damaged/destroyed) by low pH and high temperaturesNucleic AcidsRNA: ribonucleic acidContains the pentose sugar called riboseDNA: deoxyribonucleic acidContains the pentose sugar called deoxyriboseTranscription Largest organic compounds in the body

Cellular LevelCell TheoryCell is the basic structural and functional unit of all organismsAccording to the PRINCIPLE OF COMPLEMNTARITY of structure and function, the biochemical reactions occurring in a cell are dictated by the subcellular structures present in the cellReproduction has a cellular basis200 types of cells in the body with specific functionsCell diversity: different shapes/sizesCells that connect body parts, form linings or transport gases: epithelial cells, fibroblastsCells that move organs and body parts: muscle cellsCells that store nutrients: fat cellCell that fights disease: macrophageCell of reproduction : spermCell that gathers info and controls body functions: nerve cell3 main parts of cellplasma membrane: defines the boundary of a cellvery thincomposed of 2 layers of phospholipids (lipid bilayer) arranged tail to tail with the polar hydrophilic heads exposed to the aqueous extracellular fluid and the intracellular fluidembedded membrane proteins and cholesterol are in constant flux : fluidityFLUID MOSAIC MODELCholesterol insert between the phospholipids tails to stabilize the plasma membrane= maintains the integrity of the plasma membrane 2 types of plasma membrane proteins 1. Integral proteinsspan the plasma membrane exposed on one surface or both surfaces of the membraneexposed on both surfaces: TRANSMEMBRANE proteins2. Peripheral proteinsattached to integral proteins of the phospholipids heads on the cytoplasmic face of the plasma membraneThese membrane proteins act as transporters- bring polar molecules across the membranereceptors-span the plasma membrane for neurotransmitters and hormonesenzymatic activityintercellular joiningcell-cell recognition: glycoprotein act as ID tags that are specifically recognized by other cellson the extracellular surface of cells, accumulation of glycoprotein and glycolipids form a structure called the GLYCOCALYXglycoprotein= membrane protein+ carbohydratesthe pattern of carbohydrate arrangement is unique to each cell type. Hence, the glycocalyx acts as a molecular (biological) marker for cell-cell recognition EX: the glycocalyx on the surface of the ovum (egg) is recognized by the spermsperm approaches the ovum to bindSudden changes in the pattern of the carbohydrate arrangement in the glycocalyx indicates the cells are turning cancerous3 Membrane Junctionsexist between adjacent cells in a tissue1. Tight junctionintegral proteins of adjacent cells fuse to form an impermeable junction between cellscan only take things acrossEX: blood brain barrier between the blood in capillaries and the neurons in the brain---BBB prevents the exposure of these neurons to toxinsEX: cells lining the gastric wall (tight junctions prevent seeping)2. Desmosomelinker proteins inserted in the space between the adjacent cells to hold the cells togetherprevents cells from pulling apart under stressANCHOR CELLS: ANCHORING JUNCTIONAbundant in areas of the body subjected to stressPresent in epidermis of the skinEX: heart wall: cardiac muscle3. Gap junctiontransmembrane proteins called CONNEXONS: hollow cylindrical tubes that connect adjacent cellsconnexons act as channels to allow for the rapid transfer of ions for the rapid transfer of electrical current from cell to cellreferred to as COMMUNICATING junctionspresent in cells that are electrically coupled and contract as a single unit: functional syncytiumelectrically coupled tissue functions as a single unit: all cells contract almost at the same timeex: smooth muscleMEMBRANE TRANSPORT: Plasma membrane is a selective barrierPassive process: substances cross the membrane without any energy input1. Diffusion3 subtypesSimple diffusion: hydrophobic/nonpolar/ lipid soluble substances easily diffuse through the lipid bilayer of the plasma membrane down their concentration gradientdiffuse from areas of HIGHER concentration to areas of LOWEREX: O2 diffuses from the fluid outside the cell into the cell and CO2 diffuses from cell interior to the cell exterior Facilitated diffusion: involves carrier proteins: integral proteins imbedded in the plasma membraneLipid insoluble/polar/hydrophilic substances are carried across the lipid bilayer of the plasma membraneEX: glucose and amino acids use facilitated diffusion to move into the cell Carrier proteins: once they are engaged in transporting the substance; transport maximum is reached: SATURATION: represented graphically by the sigmoid curveOsmosis: water will move from an area of lower solute concentration to an area of higher solute concentration2. Filtrationa passive process- no energy inputmovement of solution from area of higher pressure to area of lower pressure; down a pressure gradient Active Processes: cell provides energy (ATP) required to move substances across the membrane1. Active transport: movement of solutes/ions from area of lower solute concentration to area of higher solute concentration (against concentration gradient)mediated by carrier proteinsexhibits saturation and specificity SOLUTE PUMPING2. Vesicular transportexocytosis : movement of substances out of the cell (enclosed in vesicle) secretory cells use exocytosis to secrete their content to the cells exterior ex: hormones and enzymes are secreted this wayendocytosis: movement of substances into the cellphagocytosis: movement of solid particles from the exterior into the interior; enclosed in vesicles: PHAGOSOMESlysosomes (cytosplasmic organelles that contain powerful digestive enzymes called LYSOZYMES) fuse with the phagosomes to digest it and its contentscells that perform phagocytosis: PHAGOCYTESphagocytes are present in the immune system (destroy pathogens: disease causing micro-organisms)ultimate phagocyte: MACROPHAGEmay be clumps of bacteria or cell debrisnot all cells are capable of thispinocystosis: movement of solution into cells by enclosing the solution in vesiclesbulk phase endocytosisall cells go through pinocytosis to obtain nutrientsreceptor-mediated endocytosis: receptors bind to specific substances and are taken into the cell LDL binds to LDL receptors on the plasma membrane of steroidgenic cells (cells that produce steroid hormones)Exhibits specificity and saturationEndocytosis and ExocytosisTrancytosis: Movements of substances enclosed in caveolae into a cell, across the cell and released on the opposite side of the cell via exocytosisVesicular Trafficking: Intracellular movement of substances in coatmer- coated vesicles from organelle to organelle within the cell Resting Membrane Potential (RMP)Plasma membrane is very receptive to potassium ionsMore potassium ions inside and more sodium outsideMore potassium ions leave the cell than sodium ions coming in because plasma membrane is more permeable to potassium ionsTherefore cytoplasmic surface is negativeSeparation of charges causes the RMPTONICITYMovement of water in and out of cells can shape or tone of cellsIsotonic: concentration of solution inside and outside of the cells is the same; same amount of water moves in and outs; shape remains the sameHypertonic:Hypotonic: placed in solution with a lower concentration than solution inside cells; water moves via osmosis into the cells- cells swell and eventually burstCytoplasm- the interior of the cell between the plasma membrane and the nucleus; contain cytoplasmic organellesContains cytosol, cytoplasmic organelles and inclusions (not all cells have these)Membranous organelles MitochondriaDouble membrane enclosing a fluid matrix (outer and inner membrane)Inner membrane contains cristaeContains own DNA: self-replicating organelleERSmooth ER: lipid transport, lipid metabolism, lipid synthesissteroidgenic cells have prominent smooth ER which is the site of the synthesis of steroid hormonesspecialized smooth ER is muscle cells is called sarcoplasmic reticulum which is specialized to store and release calcium ions (ca2+)enzymes on smooth ER are involved in detoxificationliver cells (hepatocytes) and kidney cells have prominent smooth ER--- site of detoxification of drugsRough ERexternal surface is studded with ribosomes ( Bound ribosomes) these ribosomes synthesize the plasma protein and secretory proteins. Rough ER is therefore abundant in secretory cells such as liver cellsRough ER is referred to as the Membrane factory because the synthesis of integral proteins and phospholipids in plasma membranes is associated with the rough ERGolgi apparatusTRAFFIC DIRECTOR OF CELLComposed of stacked/flattened membranous sacsReceives proteins/lipid from rough ER: these proteins may be modifiedAll proteins received are packaged into vesicles and tagged for their destinations3 types of vesicles1. Secretory vesicles: contains proteins released via extocytosissecretory cells---secrete proteins---will have prominent rough ER and golgi apparatus; abundance of bound ribosomes2. Vesicles that contain integral proteins and lipids destined for the plasma membrane to be incorporated into the plasma membraneVesicles containing powerful digestive enzymes that remain in the cell= LYSOSOMESLysosomes (spherical membranous organelles)Vesicles formed by the golgi apparatusbud off from golgiContain powerful digestive enzymes(LYSOZYMES) that digest vesicles and biological moleculesDigest nonuseful tissues, worn-out organelles, worn-out cellsDigest phagosomes hence, lysosomes are abundant in phagocytesStimulate glycogenolysis : break down of glycogen into glucose 6 phosphates which will then enter into the glycolytic pathwayLysozymes in lysosomes stimulate bone resorption (bone breakdown) to release stored calcium back into the bloodDEMOLITION CREWShort life span (die after 2 years)PeroxisomesAlso sphericalMembranous sacs that contain powerful enzymes that neutralize harmful free radicals (very unstable and seek to bond to other molecules to achieve stability)Free radicals are thought to play a role in the aging process2 enzymes: Oxidases and Catalasesmore peroxisomes you have, the betterFree radicals (harmful) + Oxidases Hydrogen Peroxide( harmful)Hydrogen peroxide + catalase waterNonmembranous organellesRibosomesFree Ribsomes: float freely in cytosol and synthesize proteins that stay in the cellBound ribosomes: bound to surface of rough ER and synthesize proteins that are transported to the plasma membrane and exported out of the cellCytoskeletoncell skeleton- support other cytoplasmic organelles and allow for movementsrod-like structures3 types based on function1. Microtubules: largest diameter= 25 nm widemade up of globular proteins called TUBULINSTubulins are assembled into microtubules in the CENTROSOME: microtubule organizing centerCentrosome contains 2 centrioles at right anglesEach centriole is composed of 9 triplet array of microtubulesCentrioles sprout spindle fibers required for cell divisionCentrioles form 2 types of cell extensions: CILIA AND FLAGELLUMCilia: cellular extensions that occur in large numbers on the apical (exposed) surface of cellsCilia beat to create a current to move substances across the surface of the cellsFlagellum: a single, longer cellular extension that beats to propel the cell it extends from: ONLY SPERMStructural difference between cilia and the flagellum: cilia has shorter extension and occurs in large numbers; flagellum has longer extension and only one per cellserve as tracks to transport intracellular substancesinvolved in vesicular trafficking 2. Intermediate Filaments= 10 nmmost stable type of cytoskeletontough, insoluble fibrous fibersprovide tensile strength to cells by resisting pulling forces placed on the cells3. Microfilaments: smallest diameter= 7 nm arrangement is unique to each cellinvolved in formation of cleavage furrow during cytokinesisinvolved in the changes of the plasma membrane during endocytosis and exocytosisNucleus: contains the genes which control activities of the cell A cell with one nucleus = UninucleateA cell with many nuclei = MultinucleateA cell without a nucleus = Anucleate3 main regions:Nuclear envelope (membrane)Double-layered selective membraneSimilar to plasma membrane but the plasma membrane has GLYCOCALYX and the nuclear envelope has nuclear poreNuclear pores allow molecules to enter/exit the nucleusRNA move from nucleus to cytoplasmNucleolusSynthesizes ribosomal RNA (rRNA)Each ribosomal subunit is composed of rRNA and proteinrRNA is exported via the nuclear pores into the cytoplasm where the rRNA combines with protein to form the small and large ribosomoal subunits Functional ribosome: involved in protein synthesis will be the small subunit + the large subunitEach subunit is made up of rRNA and proteinNucleoli are prominent in cells producing large amounts of proteinIndicate 3 structures in the cell that will be in the abundance or prominent in the secretory cell: A) prominent rough ERB) high levels of bound ribosomesC) high levels of nucleoliDNA is double-helix; RNA is single strandedDNA is A-T G-C; RNA is A-U G-CDNA has deoxyribose; RNA has riboseChromatinComposed of structural units called NUCLEOSOMESEach nucleosome consists of 8 histone proteins and threadlike DNA wrapped around the 8 histone proteins Function of the histone proteins in chromatin1) packing the delicate threadlike DNA to prevent DNA from twisting or breaking2) regulate the activities of the DNAwhen DNA is packaged with histone proteins the DNA is in its inactive coiled form called heterochromatindissociation of the histone proteins from DNA results in the DNA assuming its ACTIVE extended form called EUCHROMATINDNA replicationTranscriptionDNA a type of nucleic acid2 types of nucleic acidsDNARNAThe structural unities for nucleic acids are NUCLEOTIDESPentose sugarNitrogen containing basePhosphate groupNitrogen containing bases in DNA A,G,C,TNitrogen containing bases in RNA A,G,C,UCovalent bonds between A-T, G-C or A-UCell Cycle2 major sequential periodsInterphase G1, S, G2Cell DivisionMitosisCytokenisisInterphase 1st major phase of the cell cycle composed of 3 sequential subphases G1growthCell is active in producing proteinsReplication of the centrioles (in the centrosome) begin toward the end of the G1 phaseLongest phase in interphaseSgrowth and DNA synthesisMain event DNA replicationEnds with 2 identical copies of the DNA each will be passed on to each of the daughter cells formed after cytokinesisDNA replicationEnzyme: HELICASE untwists and unwinds the double helical DNA into 2 polynucleotide chains that act as templates for the synthesis of 2 complementary polynucleotide chainsThe area of the separation on the double helical DNA REPLICATION BUBBLEThe Y-shaped end of the replication bubble REPLICATION FORK1st DNA template--- complementary polynucleotide chain2nd DNA template--- complementary polynucleotide chainat the end of DNA replication you will have 2 identical DNAeach DNA is composed of the template (old polynucleotide chain) and a complementary polynucleotide chain (newly synthesized) DNA replication is referred to as SEMI-CONSERVATIVE REPLICATIONG2Synthesis of proteins that include proteins that initiate/ maintain cell divisionSuch as cyclin, cyclin-dependent kinase (cdK) and M-phase promoting factor (MPF)GO PROTEINS They give the cell the go ahead to enter into mitosisReplication of centrioles is completed Cell grows by increase in size due to protein synthesis that occurs during all the subphases of interphaseMitosis: 4 phasesCompare and contrast prophase/telophaseHyperplasia: growth by increase in cell number=mitsosisHypertrophy: growth by increase in cell sizeCytokinesis: cytoplasmic divisionCancer CellsNeoplasm: excessive proliferation of cells considered abnormalBenign- grows slowly and its confined to one locationMalignant-CANCER- grows fast and aggressively; metastasizes into other organs1st prevent DNA replication b/c without replication (S phase) there will be no reproductionInhibit the actions/production of the GO PROTEINSSUMMARY:Interphase EUCHROMATINProtein synthesis and DNA replication: ACTIVE DNACell division MITOSISInactive form of DNAHETROCHROMATINFurther condensed into short bar-like structures called CHROMOSOMEPrevent entanglement, twisting and breakage as they move in ANAPHASEProtein Synthesis 2 sequential events, transcription and translationTranscription (in nucleus)Only use one strand of DNA as the templateDNA is transcribed in pre-mRNA and the pre-mRNA is edited (introns removed, leaving exons) into mRNAThe helicase untwists and separates the 2 DNA polynucleotide chains1 chain becomes the template strand and the other becomes the coding strandThe pre-mRNA (primary transcript) is synthesized from the template using the law of complimentary of base pairingsThe template presents GTCAGT then pre-mRNA is CAGUCAAt the end of transcription you have the pre-mRNA which consists of introns and exonsIntrons do not specify amino acids; EXONS specify specific sequenceAfter transcription the pre-mRNA is edited to give the mRNA (only exons; introns are spliced out)mRNA leaves nuclear poreCoding strand (DNA polynucleotide chain not used in transcription) has the same base sequence as pre-mRNA, except a T in the coding strand is replaced by a U in the pre-mRNATranslation (in cytoplasm)Occurs in the cytoplasm and involves 3 types of RNAmRNArRNA forms part of the ribosometRNA transfer RNA; 3 base sequence attached at 1 end and an amino acid at the other end3 base sequences in mRNA is referred to as codon3 base sequences in the tRNA anti-codonTriplet = 3 base sequence in DNA is the same as the anti-codon except t in the triplet is replaced by uWhat is the significance of the redundancy in the genetic code?It avoids problems that occur from mutationsBase changes at the 3rd base has little impact on the protein but if it is the first base then it can code for an entirely different amino acid20 naturally occurring amino acids but 60 codons which takes care of minor mistakes that can occur during transcription but will not affect the type of amino acid specified

EXAM 1 NOTES10/24/13 6:47 PM

Tissues4 primary tissues: Epithelial, Connective, Muscular, NervousEpithelialCharacteristics:Polarity: lower/attached basal surface, upper/free apical layerA vascular: lack blood vesselsSupported by a basement membrane: double layeredSuperior basal lamina abutting the epithelial tissueDeeper reticular lamina abutting the underlying connective tissueConnective tissue underlies/support itVascular and provides nutrients to the overlying a vascular epithelial by diffusing through the basement membraneHigh regenerative capacityInnervatedMembranous v. GlandularMembranous= covering/liningSimple- composed of a single layerSimple Squamous: (flattened-like cells with a disc-shaped nucleus)Single layer of squamous cellsLocation:Respiratory membrane in the lungsFiltration membrane in the kidneysLines structures in the circulatory systemCardiovascular and lymphatic Specifically referred to as the ENDOTHELIUMForms part of the serous membrane where it is specifically referred to as the MESOTHELIUMFunction:As part of the mesothelium is secretes the serous fluid that acts as a lubricant to reduce friction as these structures in the ventral body cavity move Diffusion of gases in the lungs (respiratory membrane)Filtration in the kidneys (filtration membrane)As the endothelium it presents a slick, frictionless surface for the flow of fluids: blood and lymph in the lymphatic systemSimple Cuboidal: (box-like with centrally spherical nucleus)Single layer of cube-shaped cells with a centrally placed nucleiLocation:Proximal convoluted tubules (PCT) and in the distal convoluted tubules (DCT) in the kidneysSurface of the ovaries as the outer membrane surrounding ovaries where it is specifically referred to as the GERMINAL EPITHELIUMFunction:Reabsorption and secretionSimple Columnar: (long columns; elongated nucleus towards the basal surface of the cell)Single layer of tall cells with a elongated nuclei placed closer to the basal surface2 typesCiliated: in respiratory tract and uterine (fallopian tubes in the female reproductive tract)Function: PROPULSION: cilia beat to create current that moves substances undirectionallyRespiratory tract: propulsion of mucusUterine tubes: propulsion of ova (eggs) or zygotesNonciliated: in the lining of most of the structures in the gastro intestinal tractFunction: SECRETION of enzymes required for the chemical digestion of nutrients (food) in the GI tractPseudostratified columnarSingle layer of columnar cells of different heights with their nuclei also appearing at different heights giving the false impression of stratification 2 types:Ciliated: have cells endowed with GOBLET CELLS: secrete mucin that when interacts with water makes mucous Specifically referred to as the RESPIRATORY EPITHELIUM: most of the structures in the respiratory tract are lined with thisNonciliated: lines the sperm-carrying duct in the male reproductive system such as the epididymis and vas deferensPhagocytize sperm that are not ejected through the urethral orifice Stratified: composed of at least 2 layers of epithelial cells: named the epithelial cell type based on the apical surface of the epithelial Stratified squamous: several layer of epithelial cells with the cell type on the apical surface being flattened with disc-shaped centrally placed nucleiKeratinized: the cells on the apical surface are DEAD cells impregnated with a tough fibrous protein called keratinLocation: epidermis of the skinFunction: abrasive-resistant and can withstand wear and tearEpidermis acts as a physical barrier against pathogens Nonkeratinized: apical cells are not filled with keratincells are alive Location: forms the superior part of the mucous membrane which lines the tracts of the bodyopenings to the exterior. The exit and entry points of the tracts are lined with mucous membrane with the nonkeratinized stratified squamous epithelial forming part of it GI Tract:Entry point: oral cavityExit point: anal cavityBoth cavities are lined with mucous membrane composed of nonkeratinized stratified squamous epithelial over connective tissueStomach: lining is mucous membrane composed of simple columnar epithelium over connective tissueFunctions: abrasive-resistantStratified cuboidal and columnarMain function: protectionRare in human bodyLocation: duct of multicellular exocrine glands such as sweat glands, salivary glandsFunction: stratification confers PROTECTION: interlay surface of ducts because the ducts carry secreted products from the glands, these epithelia are said to be involved in secretionTransitional epithelium Location: lines structures in the urinary system that transport stored urineUreters: slender-like tubes that extend from the kidneys to the bladder; transport urine from kidney to bladderBladder: storage organ for urineSuperior part of the urethra: drains urine from the bladder to the exteriorFunction: the transitional epithelia undergoes a TRANSITION from 6 layers with cubodial apical cells to 3 layers with flattened squamous-like cells as these structures fill with urine Undergoes a TRANSITION to increase the capacity of these structures to accommodate urineGlandular: epithelial cells form the secretory portion of the duct system of multicellular exocrine glandsEndocrine: secretes their products directly into extracellular fluidExocrine: secrete products onto bodys surface2 types: Unicellular and MulticellularUnicellular goblet cells (only unicellular) which are scattered within the membranous epithelial that secrete mucin (mucin +water=mucous)Multicellular: 2 types of classificationStructural ClassificationDuct System (simple glands: unbranched duct; compound glands: branched ducts)Shape of the Secretory portionFunctional Classification=mode of secretionApocrine: apex of the secretory cell pinches off to release accumulated products (no example in human body)Merocrine: secretory cell undergoes exocytosis to release productsHolocrine: secretory cells ruptures to release its accumulated products (ex: sebaceous glands)Connective tissue1. All have a common origin: derived from embryonic tissue: MESENCHYMEExhibit a degree of vascularityComposed of 2 parts: nonliving and living portionNonliving: extracellular matrix= ground substance and fibers3 fiber typescollagen fibers: white fiberselastic fibers: yellowreticular fibersGround substanceIntestinal fluidAdhesion moleculesProteoglycans composed of glycosaminoglycens (GAGs)The more GAGs in the ground substance= the consistency of the matrix solidLiving portion: cells that are derived from mesenchyme and they produce the connective tissueFibroblasts: produce connective tissue proper (gel-like matrix)Chondroblasts: produce cartilage (semi-solid matrix)Osteoblasts: produce bone tissue (solid matrix)Hematopoietic stem cell: produce blood cellsConnective tissue properLiving portion: secreted by FIBROBLASTSConsistency of the ground substance gel-like2 subclasses (all of these will be secreted by fibroblasts)LooseAreolar: supports structures in the body hence, is also referred to as the PACKING MATERIAL of the bodyLocation: Underlying epithelial tissue in mucous membrane where the areolar CT is given a proper name: LAMINA PROPRIAThe papillary layer of the dermis (of the skin) is composed of areolar CTHighly vascularized Function: 1. Support other tissue by providing nutrients2. By virtue of the presence of the immune cells (macrophages, blood cells) in the areolar CT, its involved in the immune response 3. Excess interstitial fluid is held back inside areolar CT excess interstitial fluid in areolar CT is known as EDEMAAdipose: adipose cells= adipocytes, store triglycerides in the adipose CTLocation: surrounds and supports all structures in the bodyFunction:1. For cushioning protects structures against trauma 2. Holds structures in their correct anatomical positions 3. Provides storage form of concentrated energy1g of glucose= 4 kcal1g of proteins= 4 kcal1g of fat=9 kcalReticular: Found in lymphoid organs (lymph nodes, thymus, spleen) that contain reticular CT that form a network inside these organs called the STROMALymphoid cells reside and proliferate in the stroma to provide immunity Dense: fibrous CT because of the fiber content Regular: bundles of collagen fibers arranged in an orderly, regular fashion (all fibers face in one direction)-->Can withstand stress applied in only one direction Location: Tendons: connect skeletal muscle to bonesLigaments: connect bones to joint sitesAponeuroses: sheet-like tendons that connect muscle to muscles over skeletal structures Poorly vascularized (tendons take a longer time to heal)not taking enough nutrients in as fast as you can to repair Irregular: contains bundles of collagen fibers arranged in an irregular fashion (fibers face in all directions) withstand stress applied Highly vascularized and provides nutrients to the structures it surrounds/supports Elastic: dense regular CT but with elastic fibersFunction: exhibit the stretch-recoil propertiesLocation: ligamenta flava which connect adjacent vertebraeCartilage: secreted by chondroblasts; semi-solid matrix due to high levels of GAGs; a vascular; surrounded by PERICHONDRIUM (composed of dense irregular CT) that provides nutrients to the cartilage3 typesHyaline: most abundantEmbryonic, Epiphyseal, Articular and Costal cartilageStructureAppears glassy under light microscopeSmooth appearance without obvious bundles of collagen fibers Shallow concavities called LACUNAE inside the semi-solid matrix matured chondroblasts called chondrocytes reside in the lacunae LocationMost of the embryonic skeleton is composed of hyaline cartilage after ossification, some of the hyaline cartilage persists as 1) epiphyseal plates located at the junctions of the epiphysis and the diaphyses of the long boneEpiphyseal plates allow for longitudinal bone growth during childhood and adolescence.Toward the end of adolescence, the epiphyseal plates will close= EPIPHYSEAL PLATE CLOSURERemnants of the epiphyseal plates are the EPIPHYSEAL LINES=present in the long bones of adultsConsequence of the epiphyseal plate closure=height is determined2) Articular cartilage thin layer of hyaline cartilage that caps the ends of epiphysesArticular cartilage acts as shock absorbers cushions the ends of the epiphyses to protect against wear-and-tear as bones move at joint sites3) Costal cartilage connect ribs to the sternum costal cartilages act to anchor the ribs anteriorly Elastic: have more elastic fibers in matrix than hyaline cartilagePredominant fiber type=ELASTIC FIBERS appear as tangles in the matrix.Location: 2 areas in the human bodyEpiglottis: covers the laryngeal opening during swallowingPinna (external ear) directs sound waves into the external auditory canalFunction: allows for these structures to be stretched under stress; and to recoil when the stress is released to assume their original shape/size stretch-recoil properties of elastic structuresFibrocartilagePredominant fiber type- collagen fibersBundles of collagen fibers alternating with row of lacunae continued chondrocytesLocation:Intervertebral discs located between 2 adjacent vertebrae in the vertebral column; act as shock-absorbers to protect the surfaces of the vertebrae together with elastic CTThe fibrocartilage allows for the vertebral column to be flexiblebending Pubic symphysis joins the 2 hip bones (os coxae) hence, the pubic symphsis acts as a jointThe fibrocartilage allows for the hip bones to be slightly stretched to increase the pelvic brim to allow for the passage of the fetus during parturition (labor)= flexibility Menisci padsFibrocartilage inserted into synovial joints to improve the fit of the bones at the synovial joints decrease wear and tearBone (osseous) Tissue: cell type secreted bone tissue= OSTEOBLASTSConsistency of the matrix= solid wit lacunaeMature osteoblasts called osteocytes reside in the lacunaeSolid MatrixOrganic matrix: osteoidGround substance and fibersPredominant fiber type collagen fibersGround substance increase GAGsInorganic matrixComposed of calcium phosphate crystals, which harden the matrix to make it solidCalcium phosphate crystals embedded in bone matrix hydroxyapatitesLocation: located in bonesFunction: basically the function of bones (the organs)Blood: fluid matrix plasmaLocation: blood vesselsTransport respiratory gases and nutrients and wastesNervous Tissue 3rd primary tissueComposed of 2 cell typesNeurons: generate and transmit impulses (electrical signals)Supporting Cells: non conducting cells meaning they do not generate/transmit impulses6 typesStructure: 3 regionsCell body contains the nucleus and acts as the biosynthetic region (for protein synthesis)A centrosome (contains 2 centrioles at right angles) is absent hence, neurons are amitotic not capable of undergoing mitosisDendriteAxonEach neuron has only one axon and may have at least 1 dendrite a neuron can have several dendritesLocation: Nervous tissue forms most of the structure in the brain, spinal chord, and nervesFunction: generate and transmit impulses to other neurons or to effector cells such as skeletal muscle fibersMuscle Tissue 4th primary tissue typeOrganized with connective tissue, blood vessels, nerves to form organs called muscleSkeletal Muscle each cell is referred to as a fiber because they are long and cylindricalComposed of long cylindrical cells elongated cells are referred to as skeletal muscle fibersMultinucleateoccurs when mitosis occurs without cytokinesis or from the fusing of several cellsLength= 30 cm longWhen organized to form skeletal muscle it attaches to bone (both directly and indirectly)Combines with connective tissue, blood vessels, and nerves to form organ skeletal muscleStriated Structure: long, cylindrical, referred to as fiberLocation: organized with blood vessels and nerves to form skeletal muscle structureFunction: under voluntary control; for the voluntary contraction to cause body movement and facial expression skeletal muscle is under VOLUNTARY CONTROLCardiac Muscle TissueComposed of cells that are highly branched and uninucleate BOTH SKELETAL AND CARDIAC MUSCLE TISSUE APPEAR STRIATEDFunction of the branching cardiac cells appear dark under the light microscope these junctions are called intercalated discsIntercalated discs house 2 types of membrane junctions:Gap JunctionsDesmosomesLocation: organizes into cardiac muscle, the organ located only in the middle layer of the heart wall = the myocardiumFunction: cardiac muscle contracts under involuntary control to eject blood from the chambers in the heartCells form gap junctions so they hold together, uninucleateInvoluntary controlSmooth Muscle: Composed of spindle shaped cellsUninucleate cellsOrganizes to form the organ called smooth muscle2 types of smooth muscle organsSingle Unit:Function: cells located in the walls of hollow structures in the bodys tract contract under involuntary control to push substances down the tractsMulti-Unit:Function: contract under involuntary control to regulate the width or to regulate other structuresEx: Arrector Pilli Muscle in the DermisIn cold temperatures, the arrector Pilli muscles contract to decrease surface area available on the skin for heat lossConserve heat in the bodyCentral nuclei, no striations, arranged closely to form sheetsMembranes as Simple OrgansOrgans have at least 2 types of tissues in itSimplest type of organs in the human body is the membranesMembranes are sheet like structures composed of at least 2 types of tissuesCutaneous Membrane = SkinOverlying tissue: keratinized stratified squamous epithelial tissueUnderlying tissue: Alveolar CT (Papillary Layer) and then Dense Irregular CT (Reticular Layer)Mucus Membrane: lines structures in the tract of the bodyOverlying Tissue:At entrance and end of tract: non-keratinized stratified squamous epithelial Simple Columnar Epithelial for inner tractUnderlying Tissue: Areolar CT referred to as the lamina propriaSereous MembraneOverlying Tissue: simple squamous epithelia = MEsotheliumUnderlying Tissue: Areolar CTAlways epithelia supported by CT b/c epithelia needs nutrients from CTSynovial Membrane made up of 2 types of tissues but of the same primary class

Integumentary System-2 divisions (skin and accessory skin structures)Skin is the largest organ of the body surface area 1.2 to 2.2. square metersWeighs 9 to 11 pounds = 7% of the total body weightComposed of superficial epidermis and deeper dermisVaried thickness: 1.4 mm-4.0 mmEpidermisBased on thickness= 2 types of skinThin skin= epidermis is composed of 4 strata4 strata from deep-superficialstratum basalestratum spinosumstratum granulosumstratum corneumThick skin= epidermis is composed of 5 strataPalms, internal surface of fingers, soles of the feet5 strata from deep-superficialbasalespinosumgranulosumlucidumcorneumall 4 layers are wider than in thin skinadditional layer of the stratum lucidum above the stratum granulosum and below the stratum corneum Stratum Basale deepest stratum of the epidermis abutting the basement membrane above the dermis Single layer of cuboidal cells called KERATINOCYTES (mitotically active always undergoing mitosis to produce cells that occupy more superficial strata)Because the keratinocytes are constantly undergoing mitosis, the stratum basale is also known as the STRATUM GERMINATIVUMMelanocytes produce melanin that is enclosed in melanosomes (arrange on the top/superficial sides of the keratinocytes in the stratum basale)Melanin acts as a chemical shield protecting the mitotically active keratinocytes from mutations that can occur by the UV radiation in sunlightMerkel cellscouple with the nerve endings in the papillary layer of the dermis to form MERKEL DISCSMerkel discs act as touch receptors for light touchMerkel cells do not act as a touch receptor only MERKEL DISCSStratum Spinosum superficial to the stratum basale (immediately above the stratum basale)Composed of several layers of cells cells joined by desmosomes Cells contain intermediate filaments called TONOFILAMENTSDESMOSOMES and TONOFILAMENTS allow the stratum spinosum to withstand pulling forces without the cells separatingCells appear spinyEpidermal dendritic cells Langerhans cells act as macrophages to engulf and digest pathogens and to activate the specific immune response if the pathogen gains access to the bodyHence, intact epidermis is our first line of defense against pathogens Stratum Granulosum above the stratum spinosum3-5 layers of flattened cells filled with granules2 types of granuleskeratohyaline granules: conatin tough insoluble proteins called KERATIN that make the epidermis tough and abrasive-resistantlamellated granules: contain glycolipids that make epidermis water-proofStratum Lucidum only present in thick skin; above the stratum granulosum3-5 layers of DEAD cellslayer of the stratum appear translucent under the light microscope Stratum Corneum20-30 layers of dead, flattened squamous-like cells, hence the epidermis consists of 4-5 layers of cells is a stratified squamous epitheliumdead cells in the stratum corneum filled completely with keratincells are keratinized and the epidermis becomes the keratinized stratified squamous epithelial dead cells are coated with glycolipids epidermis is water-proof Dermis consists of papillary and reticular layerPapillary layer (superficial)Immediately below the reticular layer of the basement membraneComposed of highly vascularized areolar CTSurface of the papillary layer is thrown into involutions called DERMAL PAPILLAE House 3 structures1. Blood capillaries2. Free nerve endings: act as pain receptors3. Meissners Corpuscles act as touch receptors for light touch (= merkel discs)In thick skin the surface of the papillae are supported by mounds called dermal ridges which form impressions on epidermal surface called EPIDERMAL RIDGES=friction ridges increase friction and enhance grippingPattern of epidermal ridges are unique and basis for finger printingReticular layer (deep)80% of dermisComposed of dense irregular CTContains touch receptors for deep pressure called PACINIAN CORPUSCLESLocation of the Nervous Structures in the SkinMerkel Discs: epidermal-dermal junctions; act as light touch receptorsMeissners Corpuscles: papillary layer; light touch receptorsPacinian Corpuscles: reticular layer; deep pressure touch receptorsAccessory Structures of SkinSweat Glands (suderiferous glands)Multicellular exocrine glands2 typesEccrine Sweat Glands3 million per personabundant in palms, soles and foreheadSecrete sweat via merocrine mode of secretion also known as merocrine glands99% waterhypotonic filtrate of blood containing DERMICIDIN prevents the growth of microorganisms on the surface of the skin sweat contributes to the protective function of the skinlow pH between 4-6= slightly acidic/acidicprevents growth of microorganisms on the surface of the skinAntibodiesVitamin CSalts-NaClMetabolic wastesACIDIC MANTLE: acidic pH of sweat prevents microbial growth on the surface of the skinIntact epidermis acts as a physical barrier to the microorganismsLow pH, dermicidin, antibodies guard against growth of the microorganisms; chemical barriersEvaporation of sweat from surface of the skin depends on body heat Body heat dissipated to cause the evaporation drop in the core body temperature explains why we sweat when we feel hotApocrine Sweat Glands2000 of them in anogenital and axillary areasActivated after puberty when they are stimulated by the sex steroid hormonesSecrete a viscous, yellowish fluid onto hair follicles via merocrine mode of secretionSecretion is associated with body odor also known as ODERIFEROUS glands2 special sweat glandsceruminous glandslocated in lining of external ear canalsecrete bitter substance: CERUMEN (ear wax) that prevents entry of foreign substancesmammary glandslocated in breastssecrete milk to feed the young Sebacous Glands (Oil Glands)Simple alveolar glandsFound all over body except palms/solesSecrete oily substance called SEBUM into hair follicles and via pores to the surface of the skinSebum softens and lubricates hair and skin because the oil prevents water loss from the skin/hairsSebum also contains a bactericidal agent that destroys bacteria on the surface of the skin acts as a chemical barrier Secrete via HOLOCRINE mode of secretionWhiteheads: sebum accumulated in glandsBlackheadsAcne: inflammation of sebaceous glands from bacteriaHair=PiliShaft: region exposed above the skinIn cross section, if the shaft appears flat or ribbon-like the hair is curly; if oval wavy hair; if round straight hair Root: region below the skin enclosed by the hair follicle Hair follicle also contains the hair matrix cells in the hair matrix undergo constant mitosis to produce new hair cells New hair cells become heavily keratinized to form 3 concentric rings: inner medulla, middle cortex, outer cuticleFunctionProtects against traumaFiltration: vibrissae (nasal hairs) filter coarse particles inside inhaled hair Base of hair follicle is wrapped by the root hair plexus acts as touch receptors when the hair is bent Arrector pili muscle: attached to the hair follicle (hair follicle and hair reach the skin at an oblique angle)In cold weather, smooth muscle in the arrector pili contract hair follicle and hair are pulled from an oblique angle to a right angle position the hairs trap a layer of cold air which acts as an insulator to prevent heat loss from the body Nail scratching Skin cancer occurs in areas exposed to the harmful affects of the UV radiationHas a strong genetic disposition Basal cell carcinoma: proliferation of stratum basal basale cells. The least malignant and most common type of skin cancer (80%) grows slowlySquamous Cell Carcinoma: involves the cells in the stratum spinosum. Second most common type of skin cancer; grows rapidlyMelanoma: proliferation of the melanocytes; most aggressive type of skin cancer, highly metastatic and resistant to chemotherapy; least commonBurns Tissue damage by intense heat, radiation, electricity and chemicals such as acidsClassified based on severity: First-degree burns damage is confined to only the epidermis; associated with redness, swelling and pain; heal in 3day without medical intervention. Ex. SunburnSecond-degree burns damage to the entire epidermis and the papillary layer of the dermis; associated with blisters ( fluid collection at the epidermal-dermal junction), swelling, redness and pain; heal in 3-4 weeks if infection is preventedThird-degree burns damage to the entire skin= damage to the entire epidermis and dermis including all nerve endings hence, the burn site is not painful; subjected to infections and fluid loss; medical intervention involving grafting, fluid, protein and ion replacement are required for healingWrinklesLoss of elasticity (thinning skin, lack of moisture)Eat right, work out and drink waterEXAM 2 NOTES: TISSUES AND SKIN10/24/13 6:47 PMBotox: blocks the transmission of signals from nerves to the muscles, by hindering the production of the neurotransmitter. When used for cosmetic purposes it causes the muscle to relax giving it a smoother appearance

SKELETAL SYSTEMCartilage1. Hyaline2. Elastic3. Fibrocartilage

Bones: each bone is an organ consists of bone tissue, connective tissue coverings, blood vessels and nerves 4 classesLong: Longer than they are wide Composed of diaphysis (shaft) and 2 epiphyses (extended ends of long bone)Most are located in appendicular skeleton Short: Roughly cuboidal in shapeLocated in the wrist= carpals and ankle= tarsalSpecial types of short bones called the sesamoid bones are embedded in tendons where they direct the pull of the tendon when the skeletal muscle moves FlatFlattened bones such as the sternumTend to have a protective function= protect internal organs Cranial bones are flat bones protect the brainIrregularNot classified as long, short or flatvertebrae2 types of bone tissueCompact:Located on the exterior part of the boneMatrix is solid Appears dense and are composed of structural unites called OSTEONS Each consists of concentric rings of structures called LAMELLAE , hence compact bone tissue is also referred to as lamellar bone tissue In the core of the osteon is the Haversian canal contains blood vessels and nervesAt the junctions of adjacent lamallea lacunae= house osteoctyesOsteocytes are kept viable by nutrients delivered from blood in the blood vessels in the Haversian canal by smaller air-like canals called CANALICULIOsteocytes are kept viable because they can revert to osteoblasts to secrete new bone tissue for repair and growth of the bone SpongyLocated inside the bone covered externally by compact bone Structural units of spongy bone tissue needle-like structures called TRABECULATEIrregularly arranged creating large spaces to accommodate blood vessels and red bone marrow (also known as myeloid tissue source of blood cells and platelets and contains hemotopoietic stem cells) 2 regions of Long boneDiaphysisshaft of the long bone composed of a collar of compact bone surrounding the medullary cavityContains red bone marrow (children) and yellow bone marrow (adults)Red bone marrow in the medullary cavity of long bones produces blood cells and platelets in childrenYellow bone marrow in the medullary cavity of long bones of adults does NOT produce blood cells and platelets At the junctions of the diaphysis with the epiphyses: Epiphyseal plate : present in the long bone of childrenEpiphyseal lines: present in the long bone of adults 2 Epiphysescomposed of spongy bone tissue with red bone marrowexternally each epiphyses is covered by a thin layer of compact bone the ends of the epiphyses of long bones are capped by the ARTICULAR CARTILAGE thin layer of hyaline cartilageMembrane=2 types of CT membranes (long bones)Periosteum- the outer CT membrane that surrounds bonesDouble layered outer fibrous layer and the inner osteogenic layerInner osteogenic layer contains osteoblasts and osteoclastsOsteoblasts: bone-forming cells secrete bone tissue; derived from mesenchymeOsteoclasts: bone resorbing cellsdestroy bone tissueOuter Fibrous layer of the periosteum composed of the highly vascularized dense irregular CTContains blood vessels, nerves and lymphatic vessels these structures enter through the nutrient foramina into canals right angles to the Haversian canalsThese right angled canals are called perforating or Volkmanns canals Nutrients are delivered from blood inside the blood vessels in the fibrous layer and will go through the perforated canals to the blood vessels in the Havasian canals (central canals) to provide nutrients via canalicular to the osteocytes in the lacunaeThe perforating canals extend into the spaces within the spongy boneSpongy bone tissue stores red bone marrow in both children and adultsRed Bone marrow = myeloid tissue a source of the blood cells via a process known as hematopoiesisAttached to compact bone by tough collagenous fibers called Sharpeys fibersEndosteum single layer, contains osteoblasts and osteoclastsCovers the canals, cavitites, and the trabeculae in a bone

General structure of Flat, short and irregular bones2 thin plates of periosteal-covered compact bone with spongy bone with the traberculae covered by the endosteum in between the 2 plates

OssificationPrenatal Ossification = Osteogenisis (development of the bony skeleton form the embryonic skeleton)Intramembranous OssificationBegins after the 8th week of in utero lifeMesenchyme secrete fibrous connective tissue membrane under goes intremambranous ossification to form membrane bones All membrane bones have flat are flat bonesThe 8 cranial bones and the 2 claviclesAll membrane bones are flat bones but not all flat bones are membrane bonesEndochondrial OssificationMesenchyme produces chondroblastsChondroblasts secrete hyaline cartilage form the rest of the embryonic skeleton not formed by fibrous connective tissue membraneOssification of the hyaline cartilage to form the rest of the bones in the bony skeletonAll bones in the bony skeleton except the 8 cranial bones and the 2 claviclesEndochondrial ossification results in long bones, flat bones, short bones, and irregular bonesAfter endochondrial ossification in long bones, hyaline cartilage still persists in 2 areas as the epiphyseal plates (at the junctions of the diaphysis with the epiphysis) and at the articular cartilage (caps the ends of the epiphysis)In short, flat and irregular bones you have complete ossification of the hyaline cartilage into bonePostnatal ossification-after birthLongitudinal Ossification linear bone growth/ interstitial increases the length of bones = heightIncrease in length of the long bones due to activites in the epiphyseal plates at the junctions of the diaphysis and the epiphyses of a long boneActive zones in the epiphyseal plate looking at the proximal epiphyseal plates1. Growth/ proliferation zoneChondroblasts secrete new hyaline cartilage to add on to the epiphyseal face of the epiphyseal plateGrowth zone is proliferation of chondroblasts = hyperplasia which results in the increase in hyaline cartilage secreted onto the epiphysial face of the epiphisial plate2. Hypertrophic ZoneThe mature chondroblasts (chondrocytes) grow by hypertrophy (increase in size)Large chondrocytes require more nutrients to remain viable3. Calcification (deterioration) zone calcium phosphate crytstals (hydroxyapatites) are deposited in the matrix of hyaline cartilage calcification of the matrix = solid matrix which will cause the chondrocytes to die4. Ossification (osteogenic) zone osteoblasts move into the calcified matrix and secrete osteoid organic matrix of bone tissuenew bone tissue is added on onto the diaphyseal face of the ephiphyseal plate5. Resorption zone osteoclasts reabsorb part of the newly added bone to increase the height of the medullary cavity as the bone lengthens In children, the amount (width) of the hyaline cartilage added on to the epiphyseal face=EQUAL to the amount (width) of new bone tissue added on to the diaphyseal face of the plate WIDTH (thickness) of the plates remain the sameHowever, the proximal epiphyseal plates have shifted superiorlyThe distal epiphyseal plates have shifted inferiorlyResults in the lengthening of long bones

Hormonal Control of Postnatal Longitudinal Bone Growth (long bones)Growth hormone: stimulates hepatocytes to produce insulin-like growth factors (IGFs)Protein hormone that binds to growth hormone receptors on hepatocytes (liver cells) to stimulate the production of insulin-like growth factors (IGFs)IGFs bind to IGF receptors on the chondroblasts to stimulate chondroblast proliferation growth zone Hence, the growth promoting effect on growth hormone is INDIRECT in longitudinal bone growthSex steroid hormones (testosterone in the male and estrogens in the female) synergize with growth hormone to cause growth spurtSynergize with growth hormone to increase IGF production by the hepatocytesIncrease IGF= increase chondroblast proliferation= increase hyaline cartilage secreted on the epiphyseal face of the epiphyseal plates Equal thickness of ossified tissue on the diaphyseal faceHence, increase length of the diaphysis= increase bone lengtheningAfter synergizing with growth hormone to stimulate longitudinal bone growth, sex steroid hormones begin to antagonize growth hormone from stimulating the hepatocytes to produce IGFsDecrease in IGFs= decrease in chondroblast proliferation= decrease in hyaline cartilage secreted onto the epiphyseal faceHowever, the rate of ossification at the diaphyseal face continues and it eventually outpaces the rate of hyaline cartilage secretion the epiphyseal plates become ossified leaving a line called the EPIPHYSEAL LINE present in the long bone of ADULTS The ossification of the entire epiphyseal plates is termed epiphyseal plate closureExample of endochondral ossification occurring after birth (postnatal)Towards the end of adolescence. The sex steroid hormones antagonize the actions of growth hormone and epiphyseal plates become ossified EPIPHYSEAL PLATE CLOSUREheight determined

Appositional Bone Growth2nd type of postnatal ossificationAll bones widen and increase in diameter/thicknessBone formation on the external surface of the bone outpaces the bone resorption in the internal surface of the boneAll bones in the body undergo appositional bone growth But only long bones undergo longitudinal bone growth

Bone remodelingAdult bones constantly undergo bone formation on the periosteal surface and bone resorption on the endosteal surface bone remodelingFunctions of bone remodeling:Maintain calcium homeostasisAllow for bone repair after fracturesIn healthy adults, bone density remains constant becauseRate of bone formation= rate of bone resorptionIf the rate of resorption outpaces the rate of formation-= osteoporosis Control of bone remodelingHormonal controlHow to maintain the normal calcium levels in bloodIn the human body 1200 g of calcium1000 g stored in bones as the hydroxyapatites200g left will maintain the blood calcium levels9mg-11mg/100 cc of blood Blood calcium levels below 9 mg hypocalcemiaNeed to correct it by getting calcium stored in bone tissuePARATHYROID HORMONE (PTH) is released to stimulate osteoclasts to cause bone resorption to release calcium from bones into blood PTH stimulate bone resorption (bone breakdown) to release the calcium phosphate salts in bloodStimulates the kidneys to excrete phosphate leaving Ca2+ in blood. Also stimulates calcium reabsorption from the kidneys- increase Ca2+ in bloodPTH stimulates the synthesis of the most active form vitamin D called 1, 25 dihydroxyvitaminD Stimulates Ca2+ absorption from the small intestine SUMMARY: based on the actions of PTH increase in blood Ca2+ levels back into the normal rangeBlood calcium level above 11mg hypercalcemicYou need to store excess calcium in bone tissue as the hydroxyapatites CALCITONIN is released to stimulate osteoblasts to produce bone tissue and release stimulate mineralizationuses calcium from bloodStimulates the osteoblasts to secrete NEW bone tissueThe matrix of new bone tissue is mineralized by hydroxyapitites (calcium phosphate crystals): calcium levels in blood drop back into normal rangeMechanical force/ stresses Wolffs LawBones remodel/grow in response to mechanical stresses placed on the bonesBones that are stressed-pulled often by contracting skeletal muscles undergo bone remodeling where bone formation outpaces bone resoprtion resulting in thickening of these active bones

JOINTS=ARTICULATIONSClassification: 2 waysFunctional: based on amount of movement allowed at the joint3 typesSynarthroses-immovable jointsAmphiarthroses-slightly movable jointsDiathroses- freely movable jointsStructural: based on the material binding the body and the absence or the presence of a joint cavity3 typesFibrous joints: bones joined together by dense CT; joint cavity absent3 typessutures- present only in the skullIn children: sutures are amphiarthrotic joints In adults: sutures are synarthrotic jointsgomphoses- short periodontic ligaments that connect the teeth into the alveolar sockets of the mandible and the maxillaehence, gomphoses are referred to as PEG-IN-SOCKETS jointssynarthrotic jointssyndesmoses- ligaments or bands connect the bones fibrous materialligamentmembrane called interosseous membranecomposed of ligaments synarthrotic jointscomposed of interosseous membrane amphiarthrotic jointsinterosseous membrane between the radius and the ulna allows for pronation of the forearm Cartilaginous jointssynchondroses: joint formed by hyaline cartilageThe epiphyseal plate connecting the epiphyses and the diaphyses of a long bone are synchondrotic joints which are synarthrotic joints symphyses: formed by fibrocartilageall symphyses are amphiarthrotic joints intervertebral discs between adjacent vertebrae pubic symphyses connect the os coxae (hip bones)the pubic symphyses is an amphiarthrotic joint that moves slightly to increase the pelvis inlet during labor Synovial joints: class of joints with a joint cavity present; hence, all synovial joints are DIARTHROTIC joints=movable Unique special features1. The ends of the epiphyses of the long bones at the synovial joints are capped by the ARTICULAR CARTILAGE covers the ends of all bones forming synovial joints function: articular cartilage protects the surfaces of the bones as the synovial joints move to minimize wear and tear 2. Joint cavity: space that contains synovial fluid which acts like a lubricant to reduce friction 3. ARTICULAR CAPSULE: encloses the joint cavitydouble layered outer fibrous layer: composed of dense irregular CTinner synovial membrane: composed of areolar CT over dense irregular CTblood in the capillaries in the fibrous capsule is filtered and secreted by cells in the synovial membrane this filtrate is called the SYNOVIAL FLUID: located in the joint cavity and inside the articular cartilagefunction: synovial fluid acts as lubricant to reduce friction as the synovial joints move; synovial fluid provides nutrients to the chondrocytes in the articular cartilage; removes metabolic wastes from chondrocytes back into the blood of capillaries; synovial fluid contains phagocytes that engulf and digest cellular debris and any microbes in the joint cavity 4. Ligaments composed of dense regular CT that reinforce and stabilize synovial joints 3 types1. Intracapsular ligaments: located deep to the articular capsuleex: cruciate ligaments of the knee joint2. Capsular or intrinsic ligament: part of the fibrous capsule of the articular capsule that blends into the periosteum of the articulating bonesex: tibial collateral ligaments3. Extracapsular ligaments: external to the articular capsuleex: popliteal ligaments Additional structures that may be present at certain synovial joints to add protection1. Menisci certain types of synovial joints to improve the fit of the bones forming the synovial joint minimize wear and tear of the articulating surfaces ex: knee joint2. Bursae= bags of synovial fluid that act as ball-bearings to decrease friction at sites of active synovial joints ex: shoulder joint, knee joint 3. Tendon sheaths elongated bursae wrapped around tendons subjected to friction; decrease friction; found around tendons rubbing against muscle, ligaments and bones 6 types of Synovial joints: based on the structure of the articulating surfaces of the bones forming the synovial joints the structure and shape articulating surfaces dictates the types of movements allowedTypes of movements:1. Gliding movements gliding or slipping of the articulating surfaces2. Flexion movement which results in the decrease of the angle of a synovial joint the articulating surfaces get closer to each other 3. Extension movement that increases the angle of the synovial joint articulating surfaces separate pull away from each otherbring a flexed knee to the anatomical position is an extension 4. Abduction movement of limbs away from the midline of the body 5. Adduction movement of limbs towards the midline of the body 6. Circumduction abduct the limbs and move the digits to describe a cone in space7. Rotation movement around an axis 6 types1. Plane joint : articulating surfaces are flat Movement allowed: gliding or slipping intercarpals and intertarsals2. Hinge joint: one articular surface of one bone is cylindrical and the articular surface of the second bone is a trough; Hinge joints allow for flexion and extensionElbow joint 3. Pivot joint: the articulating surface of one bone is round and the articulating surface of the second bone is a sleeve or ring .Movement allowed: Rotationatlantoaxial joint allows for movement of the head to motion NO4. Condyloid (Ellipsoid) joint: the articulating surface of one bone is an oval protrusion and the articulating of the second bone is an oval depression. Movements allowed: flexion, extension, abduction, circumduction, adduction atlanto-occipital joint allows us to motion YES5. Saddle joint: the articulating surface of one bone has convex and concave surfaces articulating surface of the second has both concave and convex surfaces Only one location in the human body carpometacarpal joint of the thumb 6. Ball-and-socket joint: the articulating surface of one bone is spherical and the articulating surface of the second bone is s a cuplike socketThe ultimate diathrotic joint freely moveableEXAM 2: BONES AND JOINTS10/24/13 6:47 PMcoxal joints and glenohumeral joints

The Muscular System3 types of muscle tissue that organize with CT, blood vessels, lymphatic vessels and nerves to form the 3 types of organs (skeletal, cardiac, and smooth MUSCLE)Skeletal Muscle Tissuestriations, long cylindrical cells called muscle fibers; multinucleateattachment can be direct or indirectCardiac Muscle TissueStriations; branching cells with intercalated discs; uninucleateSmooth Muscle TissueNo striations; spindle-shaped cells; uninucleateSKELETAL MUSCLE (organ)Skeletal muscle tissue is composed of the skeletal muscle FIBERSEach skeletal muscle fiber is surrounded by the EDNOMYSIUMA bundle of endomysium covered skeletal muscle fibers FASICLEEach fascicle is surrounded by the PERIMYSIUMA bundle of perimysium covered fascicles SKELETAL MUSCLE Skeletal muscle is wrapped in EPIMYSIUMSkeletal muscle, the organ, attaches to skeletal structuresBone and cartilage, hence the name skeletal muscleAttach in 2 ways: direct attachment and indirect attachmentDirect attachment of skeletal muscles: muscles attach directly to the surface of bones these bones tend to be flat bones such as the cranial bonesIndirect attachment: the epimysium blends into a tendon the tendon attaches the skeletal muscle to the skeletal structures (bone or cartilage)ADVANTAGES:1. Space saver attachment via tendons occupies less space on the surface of the skeletal structures2. Indirect attachment makes it possible for skeletal structures to be moved when the skeletal muscle contracts2 attachment sites: the ORIGIN and INSERTIONThe bone that moves (the movable bone) when the skeletal muscle contracts is known as the INSERTION; and the bone that does not move ( the immovable bone) is the ORIGIN. Hence, when the skeletal muscle contracts, the insertion moves toward the origin.Each skeletal muscle fiber80% of its volume will be occupied by the myofibrils (rod-like)run the entire length of the skeletal muscle fibers skeletal muscle fibers run the entire length of the skeletal muscle organeach myofibril contains 2 types of myofilaments1. Thick filamentscomposed of protein MYOSINconsists of a tail and 2 globular heads 16 nm300 myosin form a dark band called A bandMyosin globular heads have binding sites for actin. Binding sites for ATP and contains the enzyme ATPase2. Thin filaments composed of protein ACTINanchored by the Z discs (lines)the distance between 2 successive Z discsSARCOMERESarcomere run the entire length of the myofibril and myofibrils run the entire length of the skeletal muscle fibers, which run the entire length of the skeletal muscle organ Sarcomeres are the smallest contractile units in the skeletal muscle, hence sarcomeres are referred to as the structural unit of skeletal muscleThe alternating arrangement/ pattern of the thick and thin filaments gives skeletal muscle a STRIATING appearance Contain 3 different proteinsActin: contains the binding sites for myosin globular heads; forms the structural framework of the thin filament Tropomyosin: rod-shaped regulatory protein that spirals around the actin and blocks myosin binding sites on actin in a relaxed skeletal muscle, hence actin sites are NOT accessible by the actin binding sites on the myosin headsTroponin- 3 polypeptide complex namelyTnC- binds calcium ionsTnT- binds to tropomyosinTnI- inhibitory subunit that binds to actinMyoglobin (same function of hemoglobin) unique RED pigment in skeletal muscle fibersBinds/releases oxygen (O2)Inclusions in the cytoplasm of skeletal muscle fibersCytoplasm of skeletal muscle fibers SARCOPLASMGlycosomes contain glycogen: storage form of glucose in animal cellsMitochondria aerobic respiration is used by skeletal muscle fibers to produce energy (ATP) required to sustain skeletal muscle contractionAerobic catabolism of 1 g of glucose yields 38 ATPAnaerobic catabolism of 1 molecule of glucose yields 2 ATPSarcoplasmic Reticulum (SR) specialized smooth ERSR stores/releases Ca2+ into the sarcoplasm to cause skeletal muscle contraction Expanded ends of the SR are called TERMINAL CISTERNAESarcolemma-plasma membrane of the skeletal muscle fiberTransverse tubules (T-tubules)- invaginations (infoldings) of the sarcolemma into the sarcoplasm called 3 structures in a skeletal muscle fiber= TRIAD1. Terminal Cisterna2. T-tubule3. Terminal Cisterna Sarcomeres: structural units of skeletal muscle= each skeletal muscle is composed of repeated units arranged end to end called sarcomeresComponents:A band= thick filamentsM line= line that bisects and anchors the A bandsThin filaments: alternating with A bands; this alternating pattern of thick and thin filaments results in STRIATED appearanceZ lines (z discs)= anchor the thin filamentsH zone= middle region of the A band not overlapping with the thin filamentsI bands= regions of the thin filaments not overlapping with the A bandSliding Filament Mechanism of Muscle ContractionExplains how sarcomeres shorten which leads to the shortening of skeletal muscle termed CONTRACTIONStates that the shortening of a skeletal muscle occurs when the thin filaments in the sarcomeres slide inward into the H zone (toward the M line) pulling the Z discs inward hence, sliding of the thin filaments results in shortening of the sarcomeresSarcomeres (distance between 2 successive Z discs) is shortenedSarcomeres shorten myofibrils shorten skeletal muscle fibers shorten skeletal muscles shortenAccording to the sliding filament mechanismWhen the thin filament slides into the H zone, then there is complete overlap between the thin filaments and the A band (Z discs are abutting the A bands) the H zone disappears and the I bands disappearWhat causes the thin filaments to slide into the H zone, resulting in the shortening of sarcomeres?Excitation- Contraction CouplingEach skeletal muscle (the organ) is innervated by a motor neuron via axons (conducts impulses from the central nervous system to skeletal muscles)As the motor neuron approaches the skeletal muscle, its end branches called AXON TERMINALS enter into the skeletal muscle and make contact with skeletal muscle fibers1-1 ratioEach axon terminal makes contact with 1 skeletal muscle fiber; each skeletal muscle fiber can make contact with only one axon terminalThe motor neuron and all the skeletal muscle fibers it makes contact via its axon terminals MOTOR UNIT (come in different sizes)Small motor unit 10 skeletal muscle fibers contractedAcrtivated first Medium sized 50-100Larger sized 1000 Generate the most force; activated lastExplains how action potential developed/transmitted by the axon of the motor neuron is coupled to the shortening of the sarcomeres sliding of the thin filaments into the H zoneThe junction of the axon terminal with the motor end plate separated by a thin gap is called the neuromuscular junction (N-M junction)N-M junction involves the motor end plate highly folded region of the sarcolemmaIncrease surface area hence, the motor end plate has the highest number of the acetylcholine receptorsAcetylcholine. Is the neurotransmitter released into the neuromuscular cleft (gap between the axon terminal and the motor end plate)Acetylcholine diffuses from the cleft to bind to its receptors on the surface of the motor end plate When acetylcholine binds to its receptors, the motor end plate depolarizes (reversal of the resting membrane potential)Interior of sarcolemma becomes slightly less negative. Depolarization of the muscle end plate develops into action potential which spread across the entire sarcolemma, including the t-tubules (invaginations of the sarcolemma)When the action potential enters the t-tubule of the TRIAD, the terminal cisternae depolarize and Ca2+ is released from the sarcoplasmic reticular into the sarcoplasm Increase in intracellular Ca2+ levels in the skeletal muscle fiber increase in Ca2+ in the sarcoplasm of the skeletal muscle fiberCa2+ in the sarcoplasm binds to the TnC (subunit of =troponin) leads to a conformational change in the troponin which affects TnT bound to tropomyosin- results in the tropomyosin being moved from blocking the myosin-binding sitesThe sites on actin are accessible to the myosin globular headsOnly activated myosin globular heads can bind to sites on actin Activated myosin globular headsWhen the ATPase splits the ATP into ADP and Pi, these 2 are still attached to the myosin globular headsactivated myosin globular headThe activated myosin globular head binds to its accessible site on actin at a right angleThe attached myosin globular head to its site on actin CROSS BRIDGEthe ADP and Pi dissociate from the cross bridge results in the change of orientation of the cross bridge termed the POWER STROKEthe attached cross bridge changes its orientation form a right angle to an oblique angle results in the thin filaments being pulled alongThe power stroke causes the thin filament to be moved inward in the sarcomere toward the M line termed SLIDING OF THE THIN FILAMENTS INTO THE H ZONE shortening of the sarcomere shortening of the skeletal muscle How a contracted skeletal muscle relaxes1. Turn off the activation of the motor neuronAction potential are NOT being producedAcetylcholine is NOT being released into the neuromuscular cleft2. Destroy any acetylcholine in the neuromuscular cleft using the enzyme acetylcholinesterase3.Sequester (take back) the Ca2+ from the sarcoplasm into the SR4. New ATP binds to the ATP site in the cross bridge to cause cross bridge detachment from actin LACK OF ATP (complete absence of ATP) result in a contraction of the body termed RIGOR MORTISObserved in dead individual Dying cells unable to exclude calcium, calcium influx into muscle cells promotes formation of myosin cross bridgesCross bridge detachment is impossible (ATP synthesis stops after breathing stops)Deficit (shortage) of ATP is in living individual MUSCLE FATIGUE Sources of ATP to support skeletal muscle contractionStored ATP-used firstCreatine Phosphate (CP)- ATP produced from direct phosporylation of ADP by CP using the enzyme Creatine Phosphatease:CP + ADP ATP + creatineAerobic catabolism of glucose- produces most ATPAnaerobic catabolism of glucose- pyruvic acid is converted into LACTIC ACID which reduces blood pH and contributes to muscle fatigueHow is ATP generated used in skeletal muscle contraction1. ATP is hydrolyzed by ATPase to produce ADP and Pi to activate the myosin heads2. ATP is required for cross bridge detachment3. ATP is required for the sequestration of calcium ions back into the SR for storage (active transport)Factors that affect the strength/ force of skeletal muscle contraction Size of motor units activated larger motor units generate more force than smaller motor unitsNumber of motor units activated force increases as the number of motor units activated increasesRecruitment = smaller motor units are activated first followed by larger motor unitsFrequency of skeletal muscle activation force increases as the rate of stimulation by motor neurons increasesThe length of the sarcomeres prior to contraction sarcomeres at the optimum length (2.2-2.6) maximum force generated by the skeletal muscleslight overlap between the A band and the thin filaments with H zone stretched sarcomeres prior to contraction there is no overlap between the A band and thin filaments hence, the activated myosin globular heads cannot bind to their sites on actin NO SLIDING OF THIN FILAMENTSwide H zone zero tension/ force generatedif the sarcomere length is shortened prior to contraction complete overlap between the A bands and thin filaments but there is NO H zone cross bridge can form, but the thin filaments cannot slideNO H zone to slide intoZero force generated2 main categories of skeletal muscle contractionisometric contractionforce(tension) generated by the muscle is increasing at a constant muscle length ( isometric = same length); occurs when the weight exceeds the force generated by the muscle isotonic contraction muscle shortens at a relatively constant force ( isotonic = same force); force generated by skeletal muscle exceeds the weight so the skeletal muscle contracts and work is done, such as lifting the weight.3 Skeletal Muscle Fiber Typesbased on Speed of Contraction: 2 typesslow and fast fibers due to the speed at which myosin ATPase hydrolyzes ATPbased on Major Pathway for ATP Production: 2 waysaerobic respiration: oxidative fibers typesanaerobic respiration using more glycogen: glycolytic fiber types1. Slow Oxidative Fibershave the highest content of myoglobin binds and releases oxygenrequired for aerobic catabolism of glucose to yield ATPmyoglobin RED PIGMENTalso known as RED FIBERSpredominant in skeletal muscles involved in endurance-type of activities postural muscles suited for endurance-type events such as running a marathon successfully 2. Fast Oxidative Fibers

3. Fast Glycolytic fibers lowest myoglobin hence, they appear whitish and referred to as the WHITE FIBERSactivities that are short-lived but intense a lot in chest muscles and muscles of the backPectoralis major/minor, deltoid, latissmus dorsi

A skeletal muscle fiber can only undergo hypertrophyHence, muscle grows by hypertrophy and NOT by hyperplasia (cell number)Effect of Exercise on Skeletal MusclesAerobic or endurance exercise (jogging, biking, swimming) changes in skeletal muscle:Increase in capillariesIncrease in mitochondriaIncrease in myoglobin contentOverall, endurance improved= increase in staminaResistance exercise (weight lifting, isometric exercises where muscle are pitted against immovable objects) changes I skeletal muscle:Increase in the size of skeletal muscles= hypertrophy of skeletal muscles occur due to increase in the number of myofibril within each muscle fiberIncrease in glycogen contentOverall, bulky muscles generate more force=increase in muscle strength Smooth Muscle: the organNot striatedSarcomeres are absentThick filaments and thin filaments are present but not arranged in alternating pattern. Rather they are arranged diagonally Z discs are absent (dense bodies)Transverse tubuals are absent- therefore triads are absent.There are shallow concavities of the sarcolemma of the smooth muscle called caveolaeCaveolae contain extra cellular fluid rich in calciumDense bodies are present in smooth muscle cellsDense bodies- anchor the thin filamentsSR is present but poorly developed. Terminal cisternae are absentPresent is the calcium modulating protein called. CalmodulinCamodulin binds Ca++ThroponinC and the entire troponin absent in the thin filaments of the smooth muscle cells. Hence the thin filaments consist of 2 proteins- actin and tropomyosinTroponin does not block myosin binding sites on actin when smooth muscle is relaxed.Intermediate filaments are present in smooth muscle cells. Hence smooth muscle can withstand stresses placed on it. Differences between the E-C coupling in the skeletal muscle and the smooth muscle1)Skeletal muscle can only be stimulated to contract by activation of the motor neuron. Innervated the skeletal muscle. Skeletal muscle relaxation occurs when the motor neuron is not being activated. In smooth muscle can be activated to contract by2) a pacemaker activity intrinsic to the smooth muscle- pacemaker activity stimulates smooth muscle contraction, external innervationsIf present, regulates the intrinsic pace set by the pacemaker activityb) Chemicals such as hormones stimulates smooth muscle contraction . Unlike skeletal muscle, chemicals can cause smooth muscle relaxation Ex. Epinephrine- stimulates the contraction of smooth muscle in the wall of blood vessels-leading to basel constriction- the hormone atrial natricetic- causes contracted smooth muscle to relax leading to vasodilatation.3) Smooth muscle is innervated by autonomic nerve fibers and forms the DIFFUSE junctions with smooth muscle cells. Diffuse junctions are irregular with wide clefts that form between the bulbous end of the autonomic nerve fiber called a varicosity and a smooth muscle cellUnlike skeletal muscle- a smooth muscle cell can form diffuse junctions with several varicosities. No longer a 1: 1 ratio.When the autonomic nervous system is activated- the autonomic nerve fibers innervating the smooth muscle- you may cause smooth muscle contraction of relaxation aka Autonomic nervous system SympatheticParasympatheticIf the sympathetic nervous system of the autonomic nervous system is activated, the smooth muscle in the walls of the bronchial (tube like structures leading into the lungs)- the activation will cause smooth muscle relaxation . IF the Para sympathetic nervous system is activated- contraction will be the cause of the smooth muscle of the walls of the bronchialDifferences between skeletal muscle contraction (sliding o