Module 1 - Pathophysiology

define pathophysiology

the study of functional changes in cells, tissues, and organs altered by disease or injury (what is going wrong)

define pathology

the study of cell and tissue physical changes associated with disease (structure)

define pathogenesis

the study of disease (process)

define remission

when a disease gets better

define idiopathic

spontaneous, unable to recognize and name the cause

define iatrogenic

caused by a treatment or medical intervention

what is disease

acute (short) or chronic (long) illness that one acquires or is congenital (presented in birth) causes physiologic dysfunction

→ typically has symptoms and signs

differentiate symptoms and signs

symptom → non-measureable, but what the patient experiences

signs → measurable, and visible to other witness that are not the host

define etiology

something that causes a disease (ex. virus)

define cellular adaptation

changes in size, number, or type of cell to permit survival of cell under stress

5 principles of adaptation: atrophy

decrease in size

→ ex. normal: thymus gland

→ ex. pathological: brain, muslces

5 principles of adaptation: hypertrophy

increase in size

→ ex. skeletal/heart muscle, cannot undergo mitosis

5 principles of adaptation: hyperplasia

increase in the number of cells, occurs with cells that are capable of mitosis

→ ex. liver, breasts

5 principles of adaptation: metaplasia

reversible replacement of one mature cell type by another

→ ex. in smokers along respiratory tract

5 principles of adaptation: dysplasia

abnormal changes in size, shape, and organization of mature cells (precursor of cancer, but can be reversed)

→ ex. cancerous cells in cervix and respiratory tract

5 principles of adaptation: intracellular accumlation

represent buildup of material that the cell cannot metabolize

5 principles of adaptation: calcification

represents buildup of calcium salts in tissues

• can occur in…

  → damaged: from dead cells

  → normal: excess calcium levels

what are the different types of intracellular accumulation

• endogenous (something normally produced by cell)

  → substance produced faster than it is used

  → pigments

• exogenous (external source)

  → macrophages and phagocytes ingests pigment to get rid but fails

define crystilization (calcification)

tissue becomes stiffer from dying cells leaking calcium over time

define cell injury

when cell can no longer maintain the applied stress or cannot adapt (where most diseases begin)

what are the 4 major causes of cell injury

physical agents, chemical, biological, nutritional

3 mechanisms of cell injury: hypoxia

lack of sufficient oxygen for cells (most common cell injury)

CAUSES

• ischemia (reduced blood supply to cell in one area)

  → form blood clots (embolus, travelling or thrombus, stationary)

• hypoxemia (low oxygen in blood flow)

pathophysiological effect of hypoxia (go over on slides)

reduced O2 avaliability, decreases ATP production

a. increased anaerobic respiration

b. reduced activity of ATP-dependent enzymes

c. reduced activity of ATP-dependent sodium-potassium pump

d. reduced activity of ATP-dependent calcium pump

3 mechanisms of cell injury: impaired calcium homeostasis

high intracellular calcium results in:

a. activation of inappropriate enzymes that causes cell damage

b. increased mitochondrial permeability

3 mechanisms of cell injury: free radical

highly reactive: non-specific attack to DNA, proteins and lipids which cause cell damage and disease

define free radicals

unstable molecules containing unpaired outer electrons (ex. reactive oxygen species, ROS)

differentiate the types of free radicals

exogenous: absorption of radiation, cigarette smoke or pollution

endogenous: general metabolism, drug breakdown, or produced by phagocytes

define apoptosis

programmed cell death cause (cell suicide) when cell is no longer healthy to carry on

• ATP

• only affects selected cells

• cell SHRINKS

• no inflammation

define necrosis

unregulated, chaotic cell death due to injury

• cell BURSTS

• damages nearby tissues

• inflammatory

4 types of necrosis: coagulative

caused by hypoxia and characteristic of infarcts

• protein denaturation occurs → tissue becomes firm and opaque

4 types of necrosis: liquefactive

occurs in focal bacterial or fungal infections

• tissues soften and liquefy → cells digested → abscess forms

4 types of necrosis: caseous

combination of coagulative and liquefactive

• crumbly yellowish, often enclose with granuloma

4 types of necrosis: fat

areas of fat destruction

• results in leakage of pancreatic lipases into peritoneal cavity → peritoneal fat digested into glycerol and fatty acids → fatty acids combine ions

review gangrene necrosis

lack of blood flow, cannot feel tissue area

• dry = due to coagulative necrosis

  → dry/wrinkly, extremeties

• wet = due to liquefactive

  → cold/swollen/black, internal organs

• gas = infection from species of bacteria

  → enzymes destroy connective tissue and cause bubbles of gas

what are the 2 theories of aging

programmed (molecular): genetic

damage (sensecenes): accumulation of DNA damage due to random events