Foundations of Pathophysiology Overview

What is the chemical makeup of the cell membrane and its primary function?

Phospholipid bilayer with cholesterol and membrane proteins; provides a selective barrier, regulates transport, and facilitates cell signaling and homeostasis.

What is the function of the nucleus in a cell?

Houses the cell's genetic material (DNA) and controls cellular activities through gene expression.

What is the role of ribosomes?

Site of protein synthesis for the cell.

What is the primary function of mitochondria?

Powerhouse of the cell; generates ATP through aerobic respiration.

What is the rough endoplasmic reticulum responsible for?

Synthesis and initial folding of proteins destined for secretion or membranes.

What is the Golgi apparatus' main job?

Modifies, sorts, and packages proteins and lipids for secretion or delivery to their destinations.

What is the function of lysosomes?

Contain digestive enzymes that break down waste, cellular debris, and foreign material.

What is glycolysis and where does it occur?

Anaerobic breakdown of glucose in the cytoplasm yielding pyruvate and a net gain of 2 ATP per glucose.

What happens in the Krebs cycle (citric acid cycle)?

Occurs in the mitochondria; produces NADH and FADH2 and releases CO2 as acetyl-CoA is oxidized.

What is the role of the electron transport chain in energy production?

Transfers electrons through a series of proteins to create a proton gradient that drives ATP synthesis (oxidative phosphorylation); requires oxygen.

Approximately how many ATP are produced per glucose in aerobic respiration?

About 30–32 ATP per molecule of glucose.

What is passive transport?

Movement of substances down their concentration gradient without cellular energy; includes diffusion, osmosis, and facilitated diffusion.

What is active transport?

Movement of substances against their concentration gradient that requires energy (ATP); includes primary and secondary active transport.

What is the Na+/K+-ATPase pump and its function?

A primary active transporter that pumps 3 Na+ out and 2 K+ in per ATP, maintaining essential ion gradients.

What is facilitated diffusion?

Passive transport where carrier proteins help substances move down their concentration gradient.

What is hypertrophy in cellular adaptations?

Increase in cell size due to increased functional demand or hormonal stimulation.

What is hyperplasia in cellular adaptations?

Increase in the number of cells, leading to tissue enlargement.

What is atrophy in cellular adaptations?

Decrease in cell size and tissue mass due to reduced workload, aging, or diminished blood supply.

What is metaplasia in cellular adaptations?

Replacement of one differentiated cell type with another; usually reversible if the stimulus is removed.

What is dysplasia in cellular adaptations?

Disordered growth with variation in size and shape of cells; may precede neoplasia.

What is ischemia in cellular injury?

Reduced blood flow leading to insufficient oxygen and nutrient delivery to tissues.

What is hypoxia and how does it relate to cell injury?

Oxygen deficiency at the tissue level; a leading cause of cell injury and potential cell death.

What is the difference between necrosis and apoptosis?

Necrosis is uncontrolled, often inflammatory cell death; apoptosis is programmed, orderly, and energy-dependent with no inflammation.

What is coagulative necrosis?

Type of necrosis where tissue architecture is preserved for a period due to protein denaturation, common in solid organs after ischemia.

What is liquefactive necrosis?

Necrosis where tissue is digested leading to liquefaction, common in the brain and abscesses.

Why is distinguishing necrosis from apoptosis important?

Because they have different triggers, energy requirements, and inflammatory responses, affecting prognosis and treatment.

What are common etiologies of cell injury?

Hypoxia/ischemia, toxins, infectious agents, immune reactions, genetic/nutritional factors, and physical or mechanical stresses.

What are two examples of electrolyte imbalances and their general clinical implications?

Hyperkalemia (risk of cardiac arrhythmias) and hyponatremia/hypernatremia (neurological symptoms, fluid imbalance effects).

What are common electrolyte disorders to know for clinical signs?

Potassium: hyperkalemia/hypokalemia; Sodium: hyponatremia/hypernatremia; Calcium balance considerations (briefly mentioned in electrolyte topics).

What are typical fluid imbalance disorders and their clinical implications?

Dehydration (loss of body water; can lead to hypernatremia and hypovolemia) and fluid overload (edema, hypertension, pulmonary edema); both affect tissue perfusion and electrolyte balance.