Altered Cellular Functions

Adaptation

Adaptation

A reversible response involving structural or functional modifications to accommodate both physiologic (normal) demands and pathologic (adverse) conditions.

Atrophy

Decrease in cell size.

Hypertrophy

Increase in cell size.

Hyperplasia

Increase in cell number.

Metaplasia

Reversible replacement of one mature cell type by another, less mature cell type or a change in cell phenotype.

Dysplasia

Deranged cellular growth, not considered a true cellular adaptation, but rather atypical hyperplasia

Hypoxia

Lack of sufficient oxygen within cells, most common cause of cellular injury

Ischemia

Reduced supply of blood, and therefore oxygen as well; MOST COMMON CAUSE OF HYPOXIA

Ischemia-reperfusion injury

Additional cell injury after blood flow restoration, can cause cell death

ROS

Reactive molecules from molecular oxygen formed as a natural oxidation species in cells during mitochondrial respiration and energy generation

Free radical

Electrically uncharged atom/group which has an unpaired electron

Xenobiotics

Compounds + chemicals that have a toxic, mutagenic, or carcinogenic property (ex: fungal mycotoxin)

Biotransformation

Process where enzymatic reactions convert 1 chemical into a less toxic or nontoxic compound

Antioxidants

Molecules that inhibit the oxidation of other molecules, preventing the formation of free radicals; terminate the chain of reaction (can be endogenous or exogenous)

Endogenous antioxidants

Produced by the body; SOD, ALA, CoQ10, GPX

Exogenous antioxidants

From outside the body, like dietary sources; vitamin C

Cellular swelling

Most common degenerative change, results from extracellular water going into the cells

Oncosis

Progressive vacuolation results in cytoplasmic swelling; hydropic degeneration

Necrosis

Cellular death, dissolution of cellular components, sum of cellular changes after local cell death, INFLAMMATORY RESPONSE (pain, swelling), karyolysis and sometimes karyorrhexis

Coagulative necrosis

Occurs as result of protein denaturation, albumin is turned into a firm opaque substance, *COMMON, caused by an infarct from ischemia, happens in all organs except the brain

Liquefactive necrosis

Results from ischemic injury to the brain, often triggered by bacterial infection/fungal

Caseous necrosis

Results from tuberculosis (lungs only); Dead cells not entirely hydrolyzed; causes a granuloma formation

Fatty necrosis

Cellular dissolution caused by lipases, found in breast, abdominal, and pancreas, saponification

Gangrenous necrosis

Tissue death from severe hypoxic injury; dry, wet, and gas; Ischemia -> infarct

Dry gangrene necrosis

Coagulative necrosis from loss of blood supply, skin becomes dry and shriveled

Wet gangrene necrosis

More lethal form, infection from gram-positive cocci, gram-negative rods; especially Clostridium spp.

Gas gangrene necrosis

Wet gangrene caused by Clostridium from deep puncture wounds with soil contaminated objects, Hydrolytic enzymes destroy tissue and cause gas bubbles, death within 12 hours

Apoptosis

Programmed cell death, "dropping off", NO inflammatory response, no pain; NOT pathologic, cell size shrinks

Mitochondrial (intrinsic) pathway

Inside the cell, cell becomes injured internally and signals apoptosis

Death receptor (extrinsic) pathway

Signal from outside the cells to initiate apoptosis

Autophagy

Self-destructive process that delivers cytoplasmic contents to the lysosome for degradation, NOT apoptosis, Eats self, recycling factory, occurs when cell has no nutritional support