class notes 2 - flashcards

Flashcards about cell injury, necrosis, and apoptosis.

What three factors determine the severity of cell injury?

Duration, severity of the insult, and the cell type.

Which cell type is most susceptible to injury: neurons, cardiomyocytes, or skeletal myocytes?

Neurons

What is local hypoxia also referred to as?

Oligaemia or ischaemia

Name three causes of systemic hypoxia.

Pulmonary diseases, cardiac failure, shock

Why can insulin overdose cause a coma?

It leads to hypoglycaemia, depriving neurons of glucose for ATP production.

What is the effect of cyanide on cytochrome c oxidase?

Inhibits cytochrome c oxidase in the electron transport chain.

Where does oxidative phosphorylation occur?

Mitochondrion

What is the net ATP yield per molecule of glucose under anaerobic conditions?

2 ATP

What is the net ATP yield per molecule of glucose under aerobic conditions?

38 ATP

What byproduct of anaerobic respiration causes a drop in pH?

Lactic acid

Why is adequate O2 essential for energy production?

Essential for efficient energy production from carbohydrates, lipids, and proteins.

What condition does lactic acid accumulation due to anaerobic metabolism cause?

Acidosis

What is the initial event in reversible cell injury from energy depletion by anoxia?

Cell swelling

What pump malfunctions during cell swelling, leading to sodium and water influx?

Na+, K+, ATPase pump

In reversible cell injury, what happens to intracellular potassium?

Loss of intracellular potassium to the extracellular compartment

What is the effect of increased lactic acid concentration inside the cell?

Intracellular osmole increase

What causes fine vacuolation (microvesicular swelling) in hydropic degeneration?

Water influx into the endoplasmic reticulum

What is the term for the accumulation of lipid within hepatocytes?

Also known as Fatty degeneration, hepatic lipidosis, steatosis, or macrovesicular swelling

What stain identifies fat droplets?

Oil-red-O

What happens to the calcium gradient between extracellular and intracellular spaces during reversible injury?

Calcium influx elevates the intracellular calcium concentration

Name three Ca++ dependent enzymes that are activated during cell injury.

Phospholipase A, proteases, ATPases and endonucleases

What is the effect of phospholipase A on cell membranes?

Damages cell membranes

What cell structure is damaged by proteases?

Cytoskeletal filaments (microtubules, actin, myosin)

What are four changes associated with damage to cell membranes?

Cell swelling, phospholipase A digests cell membranes, proteases damage cytoskeleton, loss of surface structures, formation of membrane blebs, leakage of cellular enzymes into the bloodstream

What is the result of calcium influx into mitochondria during irreversible cell injury?

Mitochondrial swelling and formation of amorphous densities

Which hydrolases are released from lysosomes during irreversible cell injury?

Acid hydrolases

What causes the cytoplasm to stain pink in HE-stained histologic sections?

Loss of RNA due to RNAases

Define pyknosis.

Further clumping of chromatin

Define karyorrhexis.

Fragmentation of the nucleus

Define karyolysis.

Dissolution of the nucleus

What are \"myelin whorls\"?

Fragmented plasmalemma and organellar membranes

What is dystrophic calcification?

Calcification that occurs in dead cells

Give three examples of agents that damage cell membranes.

Certain bacterial toxins (exotoxins), infections with cytolytic viruses, lytic complement components, cell mediated cytotoxicity, physical agents, chemical agents

What can leakage of cytochrome c trigger?

Apoptosis, if the cell has enough ATP

What cellular process is generally initiated if DNA damage cannot be repaired?

Apoptotic cascade

What is a free radical?

Molecules that have an unpaired electron.

What is the Fenton reaction?

An important mechanism for production of hydroxyl radical: H2O2 + Fe++ \rightarrow HO• + OH- + Fe+++

Explain the Fenton Reaction

An important mechanism for production of hydroxyl radical