AP Biology – Skeletal, Muscular, Digestive, Respiratory Systems SG

For review, see AP Biology – Invertebrates I & II, Vertebrates SG

A) Skeletal System (see practice diagrams)

~bones function as structure, support, and protection*stores calcium, phosphorus, iron, copper etc.*makes blood in the marrow through hemopoiesis –erythrocytes (RBCs) and

leukocytes (WBCs)*axial skeleton – skull, spine, and ribs*appendicular skeleton – limbs and girdles (pectoral and pelvic)

~types of bones:*long bones – curved for strength (legs and arms)*short bones – cubed shaped (wrist and ankle)*flat bones – thin; provide protection and space for muscle attachment (skull, ribs,

sternum, and scapula)*irregular bones – complex shaped (facial bones and vertebratal column)

~structure of bones:*spongy – web-like structure of hard bone; spaces are filled by soft tissue; at the end of long bones but makes up the short, irregular, and flat bones; soft tissue (red marrow) is the red of RBC formation*compact – thick dense hard bone; composes the lengthy part of the bone; center cavity contains yellow marrow (fatty material); contains nerves, blood vessels and living bone cells (osteocytes); control calcium deposition/withdrawal

~the basic system of bones is called the Haversian system or osteon*osteoblasts form the bone while an osteocyte produces the bone tissue (mature, dead osteoblasts)*the central canal is a circular channel running longitudinally in the center of an osteon containing blood/lymph vessels and nerve cells*canaliculi connect the osteocytes by small channels

~ossification is the formation of bones either by intramembranous (directly in membranous tissue) or endochonral (replacement of cartilage)~bones are movable by connection of ligaments (join the joint to the bone)

*sutures are immovable joints that compose the skull*gliding move back and forth (wrist)*pivotal move back forth in one place (vertebrate in the neck)*ball-and-socket has free rotation (shoulder and hip)*hinge extends and retracts in one place/one direction (knee)

B) Muscular System (see practice diagrams)

~each muscle contains rod-shaped bundles of fibers made up of myofibrils*myofibrils contain thin (actin protein) and thick (myosin protein) filaments*the sarcoplasmic reticulum surrounds the myofibrils with calcium for the

contraction*the myofibrils contract due to sarcomeres (region between the “z” lines)

~contraction occurs by the sliding filament theory:*(1) Stimulated by a nerve impulse, (2) the sarcoplasmic reticulum release calcium ions into the contractile units. (3) The actin or thin filaments contain

troponin, which attaches to calcium and then attaches to tropomyosin proteins. (4) The tropomyosin shifts and exposes cross-bridge binding sites in which (5) the myosin or thick filament and ATP attach. (6) Actin filaments slide past the myosin filaments with ratchet movement which is the (7) contraction of the (multiple) sacromere and the contraction of a muscle.

~skeletal – attaches bones and moves parts of the skeleton*striated muscle (lines) that is also voluntary*controlled by motor neurons that are part of the voluntary nervous system*a tendon attaches muscles to bones (origin – attach of a muscle tendon to stationary bone / insertion – the end of the muscle attachment to the movable bone)

~smooth muscle is involuntary or visceral muscle with no striations*found in internal organs, walls of blood vessels, iris of the eye, a hair’s base, and

the uterus*controlled by the autonomic nervous system – controls activities below the

conscience level~cardiac muscle pertains only to the heart

*controlled by the autonomic nervous system*cells are cylindrical and striated – cells have interlocking borders for

transmission of nerve impulses

C) Digestive System

~food is the main source of cellular energy in the human body*needed for muscle contraction, never impulses, cell absorption activities

~food enters the digestive system through a process:*ingestion – taking food into the body*movement of food along the digestive tract*digestion – breakdown of food by chemical/mechanical processes*absorption – passage of digested food from the tract into the blood for absorption*defecation – elimination of indigestible matter out of the body

Accessory Structures

~includes the teeth, tongue, salivary glands, liver, pancreas, and gallbladder

*teeth – grow in jaw sockets1) incisors: frontal;

gnawing/cutting2) canines:

capturing/killing/tearing3) molars/pre-molars: grinding

*tongue – moves food in swallowing position

*salivary glands – parotids, submaxillaries, sublinguals – secretions include water, ions, mucus, and amylase (starch splitting enzyme)

Gastrointestinal Tract (Alimentary Canal)

~includes the continue tube running through the human body; through the ventral cavity from the mouth to the anus (approx. 30 feet)

~in order:

1) mouth, teeth, tongue, salivary glands

2) esophagus

3) stomach4) small intestine, liver, pancreas5) large intestine (colon)6) rectum7) anus

~food enters the mouth and is (mechanical digestion) reduced by the teeth, saliva, and tongue creating a bolus

*the tongue presses the bolus against the palate (closes off nasal cavity) and back toward the pharynx

*larynx elevates by bending the epiglottis (closes the windpipe during digestion) and the food enters the laryngopharynx which moves down the esophagus by peristalsis (muscle contractions)

~digestive system pathway begins with the mouth and down the esophagus and into the stomach

*the stomach pH level is generally an acidic “1 to 3” – stomach lining glands secrete gastric juices (pepsin and hydrochloric acid) in conference with gastric lipase (fat-splitting enzyme)*the stomach lining of “mucin” forms as a coat to keep the enzymes and acids

from hurting the stomach*digested food enters the small intestine (first the duodenum, the jejunum, and

ileum ) to begin absorption*the small intestine’s folds, or villi, increase the surface area for absorption

~the liver secretes bile, which is stored in the gallbladder or releases into the small intestine

*bile breaks down fats (into globules) – contains cholesterol, salts, pigments, water, and amino acids*insulin is a hormone that is central to regulating the energy and glucose metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle; stops the use of fat as an energy source

~the pancreas makes sodium bicarbonate, which neutralizes the acid from the stomach

*secrete enzyme breaks down fats, carbohydrates, proteins, and nucleic acids*the pancreatic enzymes and small intestinal enzymes carry out the digestive

process~the digested/absorbed food from the small intestine will enter the large intestine

(colon)*indigestible matter will be stored in the appendix (pouch or cecum) – vestigial

organ*the ileocecal valve prevents a backflow of residue*the colon absorbs water and minerals into the blood preparing the feces*the rectum receives the dehydrated, digested, nutritionally absorbed substance*the anus expels the waster after (about) 24 hours

D)Respiratory System

~involves the pulmonary ventilation, external respiration, and internal respiration*pulmonary ventilation – inspiration and expiration of air between the lungs and

atmosphere*external –exchange of gases between the lungs and blood*internal – exchange of gases between the blood and cells

~organs include the nose, pharynx, larynx (voice box), trachea, bronchi, bronchioles, lungs, and alveoli

*nose is made of cartilage, skin, and lined with mucus*the pharynx or throat is muscular tube lined with mucus (nasopharynx,

oropharynx, and laryngopharynx)*larynx holds the vocal chords and is guarded by the epiglottis (membrane

preventing the entry of food)*trachea or windpipe extends from the larynx to the bronchi*bronchi extend into the lungs and have small clusters of absorptive tissue called

alveoli*alveoli facilitate that exchange of gases on a concentration gradient

~the lungs are the primary respiratory organ in the thoracic*inspiration occurs inside the lungs when the pressure falls below the outside pressure (diaphragm contracts to increase the thoracic cavity volume and allow the lungs to expand)

*expiration occurs when the inside pressure is higher than the outside pressure (diaphragm relaxes forcing the air to leave the thoracic cavity)

E) Vocabulary

1. Actin: globular protein that links into chains (two of which twist helically about each other) forming microfilaments in the muscles2. Myosin: protein filament that acts as a motor protein with actin filaments to cause cell contraction3. Bile: produced in the liver but stored in the gallbladder; enables the formation of fat droplets in water as an aid in the digestion and absorption of fats4. Gallstones: solid crystal deposits that form in the gallbladder5. Cellulose: a structural polysaccharide of plant cell walls; consists of glucose monomers joined by β glycosidic linkages6. Calcium: an element essential for muscle contraction and heart function; constituent of bones and teeth7. Adenosine Triphosphate: organic compound composed of adenosine and three phosphates (ATP)8. Troponin: regulatory protein that together with tropomyosin, regulates actin-myosin interactions in the skeletal and cardiac muscle contraction9. Muscle Fibers: a cylindrical. Multinucleate cell composed of numerous myofibrils that contract when stimulated

10. Diffusion: the passive transport of molecules along the concentration gradient – high to low11. Nasal Cavity: cavity in the head through in which air passes from the nostrils to the pharynx to the lungs (inhale/exhale)12. Alveolus: dead-end, multi-lobed air sacs where gas exchange occurs in a mammalian’s lungs13. Myoglobin: an oxygen-storing, pigmented protein in muscle cells14. Respiration: (breathing) the exchange of gases with the intake of oxygen and the release of carbon dioxide15. Insulin: hormones that lower blood’s glucose levels; promotes the uptake of glucose in body cells; stimulates protein and fat synthesis16. Glucose: monosaccharide that is the main source of energy and serves as an important metabolic substrate17. Duodenum: the upper part or first section of the small intestine (followed by the jejunum and ileum)18. Parietal Cells: a source of hydrochloric acid and most the water in stomach juices19. Chief Cells: secret pepsin – a proteolytic enzyme20. Canines: sharp conical teeth that are large and highly-developed for tearing meat; two canines in each jaw21. Molars: broad, rigid teeth found in the back of the jaw behind the pre-molars22. Saliva: fluid that is secrete by glands in the mouth to aid in digestion of starches23. Gastrin: polypeptide hormone secreted by the mucous lining of the stomach; induces the secretion of gastric juices produced by the gastric cells24. Amylase: an enzyme in saliva that hydrolyzes starch and glycogen into smaller polysaccharides and maltose (disaccharide)25. Digestion: the second stage of food processing – the breaking down of food into molecules small enough to be absorbed by the body26. Peristalsis: alternating waves of contraction and relaxation in the smoother muscles lining the alimentary canal that pushes the food through the canal and into the stomach27. Tendon: attaches the muscles to the one28. Ligament: a fibrous, connective tissue that joins joints and bones together29. Abdominal Coelom: the cavity of the body between the diaphragm and pelvis; contains the internal organs30. Diaphragm: a sheet of muscles that forms the bottom wall of the thoracic cavity in mammals; contraction pulls air into the lungs31. Muscle: tissue consisting of long muscles cells that can contract either by its own accord or when stimulated by nerve impulses (involuntary – organs / voluntary – skeletal)32. Mesentery: a membrane that suspends the organs of vertebrates inside fluid-

filled body cavities

F) Practice Diagrams