Cell Injury, Death, and Adaptations - Key Terms

A set of vocabulary-style flashcards covering the major terms related to cell injury, death, and adaptations from the lecture notes.

Etiology

Origin of a disease (causes and modifying factors).

Pathogenesis

How a disease develops: from initial trigger to cellular/molecular changes causing problems.

Homeostasis

Cells adjusting to maintain a stable internal state (e.g., structure, function).

Cell injury

Damage to cells when adaptation fails or stress is too much; basis of disease, can be reversible or irreversible.

Hypoxia

Lack of oxygen (most common cause of cell injury).

Ischemia

Reduced blood flow, cutting off oxygen and nutrients.

Toxins

Substances like pollution, drugs, or chemicals that harm cells.

Infectious agents

Germs (viruses, bacteria, fungi, parasites) that harm cells via toxins or immune reactions.

Immunologic reactions

Immune system attacks (autoimmune/allergic) causing inflammation and damage.

Genetic abnormalities

DNA errors (mutations, birth defects) that injure cells; key in cancer.

Nutritional imbalances

Too much or too little nutrition (e.g., vitamin deficiency, protein-calorie lack) harming cells.

Physical agents

Physical forces (trauma, heat, cold, radiation, shock) that cause cell injury.

Reversible cell injury

Cell damage that can be fixed if the cause is removed; cells often swell (hydropic change).

Hydropic change

Cell swelling from water absorption during reversible injury.

Fatty change (steatosis)

Fat buildup (lipids) inside cells, common in the liver.

Cytoplasmic eosinophilia

Injured cell cytoplasm turns red/pink when stained (due to protein changes).

Mitochondrial changes (reversible injury)

Mitochondria swell, ER expands, ribosomes detach, and chromatin changes during reversible cell injury.

Myelin figures

Phospholipid clumps from damaged cell membranes, seen in injured cells.

Necrosis

Uncontrolled, messy cell death: membranes burst, causing inflammation.

Coagulative necrosis

Tissue death where structure is kept (like a ghost outline), common in heart attacks (infarcts).

Liquefactive necrosis

Tissue turns to liquid (digested by enzymes); common in brain injury or pus-filled abscesses.

Caseous necrosis

Cheesy, lumpy cell death, typical in TB and other granulomas.

Fat necrosis

Fat tissue death, creates chalky white spots (e.g., from trauma or pancreatitis).

Fibrinoid necrosis

Bright pink, shapeless deposits in blood vessel walls, caused by immune system attacks (vasculitis).

Pyknosis

Nucleus shrinks and darkens (chromatin condenses).

Karyorrhexis

Shrunken nucleus breaks into fragments.

Karyolysis

Nucleus fades away as DNA is broken down by DNase.

Apoptosis

Planned, orderly cell suicide, no inflammation; removes unwanted/damaged cells.

Physiologic apoptosis

Normal, helpful apoptosis (e.g., during development, hormone changes, removing bad immune cells).

Pathologic apoptosis

Harmful apoptosis: when cells are too damaged to repair themselves.

Metaplasia

One cell type changes into another better able to handle stress.

Hypertrophy

Cells (and often organs) get bigger, usually from more work or hormones.

Hyperplasia

Increase in the number of cells (via more cell division).

Atrophy

Organ/tissue shrinks (cells get smaller or fewer) due to less use, poor supply, or aging.

Autophagy

Cell 'self-eats' its own parts (organelles) using special sacs (autophagic vacuoles).

Intracellular accumulations

Stuff building up inside cells abnormally (due to removal issues, overproduction, or outside sources).

Lipofuscin

Brown 'aging pigment' (wear-and-tear) seen in old or shrinking cells.

Cholesterol and cholesteryl esters

Fatty substances (lipids) that build up; key in cell membranes and artery hardening (atherosclerosis).

Glycogen

Stored sugar (glucose chains) that can build up, like in diabetes or specific organs (kidneys, heart, pancreas).

Pigments: Carbon

Black 'soot pigment' (anthracosis) from inhaled carbon, building up in lungs/tissues.

Pigments: Melanin

Natural brown/black pigment (from melanocytes) that protects skin from sun (UV).

Pigments: Hemosiderin

Yellow-brown pigment from iron buildup, found in iron-rich organs (e.g., bone marrow, spleen, liver).

Dystrophic calcification

Calcium buildup in damaged tissue, even with normal blood calcium levels.

Metastatic calcification

Calcium buildup in normal tissues due to high blood calcium (e.g., from too much PTH, Vit D issues).

Pus

Thick, yellowish liquid (dead cells, fluid) formed during bacterial infection, often in abscesses (liquefactive necrosis).

Gangrenous necrosis

Limb/tissue death (coagulative necrosis) with secondary infection, often turning mushy (wet gangrene).

Lysosomes

Cell 'recycling centers': sacs with enzymes to break down proteins, fats, sugars, and DNA.