PathophysiologyPathophysiology

Bio 395Bio 395

TerminologyTerminology PathologyPathology – focus on physical – focus on physical

changes in diseased organs and changes in diseased organs and tissuestissues

PathophysiologyPathophysiology – abnormal – abnormal functioning of diseased organs and functioning of diseased organs and how it applies to medical treatment how it applies to medical treatment and patient careand patient care

DiseaseDisease – loss of homeostasis, or – loss of homeostasis, or when physical or mental capacities when physical or mental capacities cannot be fully utilized (interruption, cannot be fully utilized (interruption, cessation or disorder in the function cessation or disorder in the function of an organ or system).of an organ or system).

EtiologyEtiology = cause of the disease = cause of the disease

When the etiology is unknown, the When the etiology is unknown, the disease is said to bedisease is said to be idiopathic idiopathic..

Iatrogenic: disease and/or injury as a Iatrogenic: disease and/or injury as a result of medical interventionresult of medical intervention

Categories of etiologyCategories of etiology Genetic diseaseGenetic disease– genes are responsible – genes are responsible

for a structural or functional defectfor a structural or functional defect Congenital diseaseCongenital disease– genetic information – genetic information

is intact, but the intrauterine environment is intact, but the intrauterine environment interferes with normal developmentinterferes with normal development

Acquired diseaseAcquired disease – disease is caused by – disease is caused by factors encountered after birth (biological factors encountered after birth (biological agents, physical forces, and chemical agents, physical forces, and chemical agents)agents)

Nosocomial – diseases acquired as a result Nosocomial – diseases acquired as a result of being in the hospitalof being in the hospital

Clinical manifestations – Clinical manifestations – indications indications that the person is sickthat the person is sick

SymptomsSymptoms – unobservable effects of a – unobservable effects of a disease reported by the patientdisease reported by the patient

SignsSigns – observable or measurable – observable or measurable traits traits

SyndromeSyndrome - a characteristic - a characteristic combination of signs and symptoms combination of signs and symptoms associated with a particular disease.associated with a particular disease.

PathogenesisPathogenesis - sequence of events in the - sequence of events in the of development of a diseaseof development of a disease

SequelaeSequelae – lesions or impairments resulting – lesions or impairments resulting from a diseasefrom a disease

Acute conditionsAcute conditions – rapid onset, develop – rapid onset, develop quickly, usually of short durationquickly, usually of short duration

Chronic conditionsChronic conditions – longer duration – longer durationonset may be sudden or onset may be sudden or insidiousinsidious

Remission – periods when clinical Remission – periods when clinical manifestations disappear or diminish manifestations disappear or diminish significantlysignificantly

Exacerbation – periods when clinical Exacerbation – periods when clinical manifestations become worse or more manifestations become worse or more severesevere

Distribution of lesions may be:Distribution of lesions may be:

LocalLocal – confined to one area of the – confined to one area of the bodybody

SystemicSystemic – widely distributed – widely distributed throughout throughout the bodythe body

Within an organ damage can be:Within an organ damage can be:

FocalFocal if there are only one or more if there are only one or more distinct sites of damagedistinct sites of damage

DiffuseDiffuse if the damage is uniformly if the damage is uniformly distributeddistributed

DiagnosisDiagnosis – identification of the – identification of the specific diseasespecific disease

TherapyTherapy – the treatment of the – the treatment of the disease to either effect a cure or disease to either effect a cure or reduce the patient’s signs and reduce the patient’s signs and symptomssymptoms

PrognosisPrognosis – prediction of a disease’s – prediction of a disease’s outcomeoutcome

Normal Functioning Normal Functioning of Cellsof Cells

Boundary – Cell Boundary – Cell membranemembrane(plasma membrane)(plasma membrane)Composed of lipid molecules in bilayer

Phospholipids have hydrophobic tailPhospholipids have hydrophilic headsAlso contains embedded proteins

proteins are important for cell-cellcommunication:

receptors for hormonescell recognition

also important for metabolic processes inside the cell:

channelspumpsenzymes

CytoplasmCytoplasmCytosol – aqueous gel-like medium

Important metabolic processes occur here

Organelles – membrane bound structuresMembranes provide compartments forseparation of chemical reactions

NucleusNucleusDNA codes for proteinsDNA codes for proteins

Rough Endoplasmic Rough Endoplasmic ReticulumReticulumContains ribosomes – make Contains ribosomes – make proteinsproteins

Smooth ERSmooth ERsynthesizes phospholipidssynthesizes phospholipidsdetoxifiesdetoxifies

Golgi ApparatusGolgi ApparatusPackages protein for exportPackages protein for export

MitochondriaMitochondriaThe cell’s power plantThe cell’s power plant

Cellular respirationCellular respiration

VesiclesVesicles“sacs” that hold molecules within a cell

lysosomes –digestive enzymesmolecules to be exported

InclusionsInclusions

Temporary structuresTemporary structures ribosomesribosomes filaments – cytoskeleton – protein filaments – cytoskeleton – protein

strandsstrands other molecules without membranes:other molecules without membranes: melaninmelanin lipids, etc.lipids, etc.

TissuesTissuesMade up of cells with common function

Four major tissue types:

1. Epithelial covering and lining

interacts with the body’s environmentglandular tissue

2. Connective tissue2. Connective tissue

Important to structure , support and protection

3. Nervous tissueMade up of neurons and supporting (glial) cells

receives info from outside (or inside) the bodyprocesses informationacts on the information through muscles, glands,

etc.

MuscleMuscle Important to movementImportant to movement Three typesThree types

– SkeletalSkeletal– SmoothSmooth– CardiacCardiac

Cells change to adapt Cells change to adapt to their environmentto their environment

Atrophy = shrinkage = decrease in cell size. Due to :

decreased use decreased blood supplydecreased nutrition

Of tissues or organs may be due to cell shrinkage or due to cell death.

Hypertrophy = increase in cell sizeResult is increased protein in

organelles, but number of cells staty the same

Hyperplasia = increase in cell numberDue to increased cell division

Uterus and breast tissueParathyroid gland in kidney failureLiver (compensatory hyperplasia)

Metaplasia = replacement of one cell type with another, still normal cellsReversible

An example: ciliated columnar epithelium replaced by stratified squamous epithelium

Dysplasia = change in cell resulting in abnormal cell size, shape or organization

in respiratory tract, cervix w/ pathology

Considered a reversible change

Neoplasia = associated with a malignant tumor

Normal Tissue

AbnormalTissue

Intracellular Intracellular accumulationsaccumulations Buildup of substances the cell Buildup of substances the cell

can’t use or dispose of.can’t use or dispose of.– Normal body substancesNormal body substances– Abnormal products from inside the Abnormal products from inside the

body (inborn errors of metabolism)body (inborn errors of metabolism)– Substances from outside the body Substances from outside the body

(transient or permanent)(transient or permanent)

Cellular injury – cell Cellular injury – cell unable to maintain unable to maintain homeostasishomeostasis Causes of cell injury:Causes of cell injury: DeficiencyDeficiency – lack of a substance – lack of a substance

necessary to the cellnecessary to the cell Intoxication or poisoningIntoxication or poisoning – –

presence of a toxin or substance presence of a toxin or substance that interferes with cell functioningthat interferes with cell functioning

TraumaTrauma – physical injury and loss – physical injury and loss of cell’s structural integrityof cell’s structural integrity

Deficiencies:

Deficiency in oxygen most important

Hypoxia = deficiency in oxygen at cellDue to :

Decreased oxygen in airDecreased hemoglobin or decreased oxygen transported to cellsDiseases of the respiratory and/or

cardiovascular system

Important to cell because of oxidative phosphorylation, which results

in the production of ATP

Oxidative: need oxygen to produce ATP

ATP: needed by cell for metabolism, cell life

Cellular response to hypoxiaDecreased mitochondrial reactions

decreased ATP produced decreased energy

Ion pumps cease, so can't regulate ions into/out of cell (ATP needed for this)

Can't pump Na+ and water out of cell, so get cell swelling organelle swelling

cell death

IschemiaIschemia is inadequate blood supply to a is inadequate blood supply to a cell or tissue.cell or tissue.

Ischemia can cause hypoxia.Ischemia can cause hypoxia.

Intoxication (or introduction of toxins into the cell)

Effect on cell depends on toxin and on cell

Some examples:Lead -- injures nervous systemCO -- deprives body of oxygenEthanol -- effects central nervous

system

Trauma -- physical disruption of cells

Ex: abrasion, cutting, burns, microorganisms etc.

ApoptosisApoptosis

““fallen apart”fallen apart” Regulated cell deathRegulated cell death During developmentDuring development Worn out cellsWorn out cells Diseased cells (tumor suppressor Diseased cells (tumor suppressor

p53 gene, natural killer or Tc p53 gene, natural killer or Tc cells)cells)

NecrosisNecrosis

Messy cell deathMessy cell death Initiates inflammationInitiates inflammation Gangrene – large mass of tissue Gangrene – large mass of tissue

undergoes necrosisundergoes necrosis

Coagulative Necrosis - Coagulative Necrosis - KidneyKidneyCoagulative Necrosis - Coagulative Necrosis - KidneyKidney

Necrosis

Fatty Necrosis - Fatty Necrosis - pancreaspancreasFatty Necrosis - Fatty Necrosis - pancreaspancreas

Necrosis

Dry GangreneDry GangreneDry GangreneDry Gangrene

Wet Gangrene 2Wet Gangrene 2º to diabetesº to diabetesWet Gangrene 2Wet Gangrene 2º to diabetesº to diabetes

Necrosis w/ liquefactive

component

Infections agentsMicroorganisms can invade and harm

cells

Cell injury can have effects on the entire body

Examples: fever, pain, increased heart rate

Cell agingCell aging

Programmed change theoriesProgrammed change theories Error theoriesError theories TelomeraseTelomerase