FMGE key terms

The body's ability to maintain a stable internal environment despite changes in the external world, achieved through negative feedback loops involving sensors, control centers, and effectors.

A regulatory mechanism in which a change in a physiological variable triggers a response that opposes the initial change, restoring the variable toward its set point; the dominant control system in the body.

A rapid, all-or-none electrical signal generated by excitable cells when the membrane potential reaches threshold, caused by sequential opening of voltage-gated sodium and potassium channels.

The steady electrical potential difference across a cell membrane at rest, typically about -70 mV in neurons, determined mainly by potassium permeability and the sodium-potassium pump.

The jumping of action potentials from one node of Ranvier to the next along a myelinated axon, greatly increasing conduction velocity and reducing energy expenditure compared with unmyelinated fibers.

The volume of plasma filtered by the renal glomeruli per unit time, normally about 125 mL/min in adults; estimated clinically from creatinine clearance or cystatin C levels.

A renal mechanism in which fluid flows in opposite directions in the descending and ascending limbs of the loop of Henle, creating an osmotic gradient that concentrates urine.

The principle that increased venous return stretches cardiac muscle fibers, increasing the force of contraction and stroke volume within physiological limits.

The volume of blood pumped by each ventricle per minute, calculated as heart rate multiplied by stroke volume; a key determinant of tissue oxygen delivery.

The proportion of end-diastolic ventricular volume ejected during systole, normally 55-70%; reduced values indicate systolic heart failure.

A sigmoid curve relating oxygen saturation of hemoglobin to partial pressure of oxygen; shifted right by increased carbon dioxide, hydrogen ions, temperature, and 2,3-BPG, facilitating tissue oxygen unloading.

The reduction in hemoglobin's oxygen affinity caused by increased carbon dioxide and hydrogen ions, promoting oxygen release in metabolically active tissues.

The cytoplasmic pathway that converts one glucose molecule into two pyruvate molecules, generating two ATP and two NADH without requiring oxygen.

The mitochondrial cycle that oxidizes acetyl-CoA to carbon dioxide, generating NADH, FADH2, and GTP; also called the citric acid or tricarboxylic acid cycle.

The mitochondrial process in which electrons from NADH and FADH2 pass through the electron transport chain, pumping protons to drive ATP synthase and produce most cellular ATP.

The synthesis of glucose from non-carbohydrate precursors such as lactate, glycerol, and amino acids, occurring mainly in the liver and kidney during fasting.

The hepatic production of ketone bodies (acetoacetate, beta-hydroxybutyrate, acetone) from fatty acid oxidation during prolonged fasting or uncontrolled diabetes, providing alternative fuel for the brain.

A model describing enzyme reaction velocity as a function of substrate concentration, characterized by Vmax and Km; Km is the substrate concentration at half-maximal velocity.

Enzyme inhibition in which an inhibitor resembles the substrate and binds reversibly to the active site, increasing apparent Km without changing Vmax; overcome by raising substrate concentration.

Programmed cell death characterized by cell shrinkage, chromatin condensation, and apoptotic body formation without inflammation, mediated by caspases.

Pathological cell death caused by severe injury, characterized by cell swelling, membrane rupture, and inflammation; classified as coagulative, liquefactive, caseous, fat, or fibrinoid.

Reversible replacement of one mature cell type by another, often as an adaptation to chronic irritation, such as squamous metaplasia of bronchial epithelium in smokers.

Disordered, atypical cellular growth with loss of normal orientation and maturation, often a precursor to malignancy but not always irreversible.

Malignant epithelial change confined to the epithelium without invasion through the basement membrane, carrying excellent prognosis if completely excised.

The lowest concentration of an antimicrobial agent that prevents visible growth of a microorganism in vitro, used to guide susceptibility testing and dosing.

An enzyme produced by some bacteria that hydrolyzes the beta-lactam ring of penicillins and cephalosporins, conferring resistance; inhibited by clavulanate, sulbactam, or tazobactam.

A structured community of microorganisms attached to a surface and embedded in an extracellular matrix, conferring increased resistance to antibiotics and host defenses.

Postmortem stiffening of muscles due to depletion of ATP, preventing actin-myosin separation; begins 2-4 hours after death and resolves after 24-48 hours depending on temperature.

Postmortem gravitational pooling of blood in dependent vessels, producing purplish discoloration of the skin; fixes after about 6-12 hours and helps estimate time since death.

The postmortem cooling of the body until it reaches ambient temperature, used with nomograms to estimate the time since death.

The number of new cases of a disease occurring in a defined population during a specified period, divided by the population at risk; measures the risk of developing disease.

The total number of existing cases of a disease in a population at a given time, divided by the total population; reflects both incidence and duration of disease.

Sensitivity is the proportion of truly diseased persons correctly identified by a test; specificity is the proportion of truly non-diseased persons correctly identified as negative.

The probability that a person with a positive test result truly has the disease, dependent on disease prevalence as well as test sensitivity and specificity.

An experimental study in which participants are randomly allocated to intervention or control groups, minimizing confounding and allowing causal inference.

The difference between systolic and diastolic blood pressure; widened in aortic regurgitation and narrowed in aortic stenosis or cardiac tamponade.

The difference between measured serum cations and anions, calculated as sodium minus chloride plus bicarbonate; elevated in ketoacidosis, lactic acidosis, and renal failure.

A 15-point clinical scale assessing eye opening, verbal response, and motor response to quantify level of consciousness after head injury or medical deterioration.

The triad of hypertension, bradycardia, and irregular respiration caused by raised intracranial pressure, indicating impending brain herniation.

A clinical scoring system assessing cervical dilation, effacement, consistency, position, and fetal station to predict the success of labor induction.

A graphical record of cervical dilation, fetal descent, and maternal vital signs plotted against time during labor, used to detect prolonged or obstructed labor.

A rapid newborn assessment at 1 and 5 minutes after birth scoring appearance, pulse, grimace, activity, and respiration, each 0-2, to guide resuscitation.

Yellow discoloration of skin and sclera in newborns due to unconjugated hyperbilirubinemia; physiological jaundice appears after 24 hours, while earlier onset suggests pathology.