1500+ medical terms, defined.

Suffix '-navir' identifies HIV protease inhibitors (e.g., ritonavir, atazanavir, darunavir, lopinavir, indinavir, saquinavir). They block cleavage of the gag-pol polyprotein, preventing maturation of HIV virions.

Minor (~5-10%) phospholipid component of pulmonary surfactant whose appearance in amniotic fluid signals near-complete fetal lung maturity. Used together with the L:S ratio to predict risk of neonatal RDS.

Most abundant membrane phospholipid and major component (~75%) of pulmonary surfactant, especially as dipalmitoylphosphatidylcholine (lecithin). Also a substrate for sphingomyelin synthesis and a marker of fetal lung maturity (L:S ratio).

Common name for phosphatidylcholine, especially dipalmitoylphosphatidylcholine - the principal surface-tension-lowering phospholipid of pulmonary surfactant. The lecithin-to-sphingomyelin (L:S) ratio is the classic test of fetal lung mat...

Fetal umbilical vessels run through the membranes over or near the internal cervical os, unprotected by cord or placenta. Rupture of membranes can lacerate these vessels and cause rapid, often fatal fetal exsanguination.

Balanced isotonic crystalloid containing sodium, chloride, potassium, calcium, and lactate; used for volume resuscitation in trauma, sepsis, burns, and surgery. Preferred over normal saline in large-volume resuscitation to avoid hyperchl...

Shock state caused by mechanical obstruction to cardiac filling or outflow, producing reduced cardiac output despite normal myocardial function. Classic causes: cardiac tamponade, tension pneumothorax, and massive pulmonary embolism.

Drugs that raise blood pressure primarily by causing vasoconstriction, used in shock when fluid resuscitation alone is insufficient. Norepinephrine is first-line in most forms of shock, especially septic shock.

Distributive shock caused by loss of sympathetic tone, classically after high spinal cord injury (above T6). Presents with hypotension and paradoxical bradycardia plus warm, dry, flushed skin.

Prolonged (>4 hour) painful penile erection unrelated to sexual stimulation, a urologic emergency that can lead to corporal fibrosis and erectile dysfunction. Most cases are ischemic (low-flow) and require urgent decompression.

Systemic Inflammatory Response Syndrome - a clinical syndrome of systemic inflammation defined by >=2 of: temperature, heart rate, respiratory rate, and WBC abnormalities. SIRS + suspected infection historically defined sepsis (now super...

Paralysis of the ciliary muscle, abolishing accommodation and causing blurred near vision. Produced pharmacologically with antimuscarinic eye drops (atropine, cyclopentolate, tropicamide, homatropine, scopolamine) and accompanied by mydr...

Leiomyoma is a benign smooth muscle tumor, most commonly occurring in the uterus (uterine fibroids). These estrogen-sensitive tumors are the most common pelvic tumor in women and can cause menorrhagia, pelvic pain, and bulk symptoms.

Nucleotides are the fundamental building blocks of nucleic acids (DNA and RNA), consisting of a nitrogenous base, a five-carbon sugar, and one or more phosphate groups. They serve crucial roles in energy metabolism (ATP), cellular signal...

PAMPs (Pathogen-Associated Molecular Patterns) are conserved molecular structures found on pathogens that are recognized by pattern recognition receptors (PRRs) of the innate immune system. They trigger immediate immune responses and inc...

The cardiac cycle is the sequence of mechanical and electrical events that occur during one complete heartbeat, lasting approximately 0.8 seconds at rest. It consists of systole (ventricular contraction and ejection) and diastole (ventri...

Hemangioblastoma is a benign, highly vascular CNS tumor most commonly occurring in the cerebellum and associated with von Hippel-Lindau (VHL) disease. It presents with cerebellar symptoms and may cause polycythemia due to erythropoietin...

Pulmonary veins are unique vessels that carry oxygenated blood from the lungs back to the left atrium of the heart. Unlike other veins in the body, they contain oxygen-rich blood rather than deoxygenated blood. There are typically four p...

The left main bronchus is the larger, longer, and more horizontal of the two primary bronchi that branch from the tracheal bifurcation at the carina (T5 level). It is approximately 5 cm long and has a more oblique angle compared to the r...

Type II pneumocytes are cuboidal epithelial cells that produce pulmonary surfactant and serve as progenitor cells for type I pneumocytes. They are crucial for reducing surface tension in alveoli and maintaining alveolar stability, preven...

Spinal cord compression is a neurological emergency caused by extrinsic pressure on the spinal cord, leading to progressive neurological deficits. Early recognition and treatment within 24-48 hours is crucial to prevent permanent paralys...

The submucosa is the connective tissue layer beneath the mucosa in hollow organs, containing blood vessels, lymphatics, nerves, and glands. It provides structural support and houses the submucosal (Meissner's) plexus in the GI tract, whi...

Patau syndrome is a rare, severe genetic disorder caused by trisomy 13, resulting in multiple congenital anomalies and profound intellectual disability. Most affected infants die within the first year of life due to severe cardiac and CN...

Anti-GBM disease is a rare autoimmune condition caused by antibodies against the alpha-3 chain of type IV collagen in glomerular and alveolar basement membranes. It presents as rapidly progressive glomerulonephritis with or without pulmo...

Spinal cord injury (SCI) involves damage to the spinal cord resulting in temporary or permanent loss of motor, sensory, and autonomic function below the level of injury. Complete injuries cause total loss of function, while incomplete in...

The right bundle branch is part of the cardiac conduction system that carries electrical impulses from the bundle of His to the right ventricle. Right bundle branch block (RBBB) causes delayed right ventricular depolarization, resulting...

Fibrinoid necrosis is a type of tissue necrosis characterized by the deposition of fibrin-like material in blood vessel walls, typically occurring in acute hypertension, vasculitis, and immune complex diseases. It results from acute vasc...

Sclerosis refers to abnormal hardening or thickening of tissue due to excessive fibrous connective tissue deposition, inflammation, or other pathological processes. It can affect various organs and is seen in conditions like multiple scl...

The anterior cerebral artery (ACA) is one of the terminal branches of the internal carotid artery that supplies the medial aspects of the frontal and parietal lobes. ACA strokes typically present with contralateral lower extremity weakne...

The ventral root is the motor component of a spinal nerve that carries efferent motor fibers from the ventral horn of the spinal cord to skeletal muscles. It contains cell bodies of alpha and gamma motor neurons that innervate extrafusal...

Type 4 RTA is a hyperkalemic, normal anion gap metabolic acidosis caused by aldosterone deficiency or resistance, resulting in impaired distal nephron acid excretion. It's the most common form of RTA and often occurs in diabetic nephropa...

Caspases are cysteine proteases that execute programmed cell death (apoptosis) by cleaving specific cellular proteins. They exist as inactive zymogens and are activated in a cascade manner during apoptosis, with initiator caspases (8, 9,...

Dendritic cells are professional antigen-presenting cells (APCs) that serve as the primary link between innate and adaptive immunity. They capture antigens in peripheral tissues, migrate to lymphoid organs, and present processed antigens...

Urinary tract infection (UTI) is a bacterial infection of any part of the urinary system, most commonly the bladder (cystitis) or kidneys (pyelonephritis). E. coli is the most common causative organism, accounting for 80-85% of uncomplic...

Uterine fibroids (leiomyomas) are benign smooth muscle tumors of the uterus, affecting 20-80% of reproductive-age women. They are estrogen-dependent growths that can cause abnormal uterine bleeding, pelvic pain, and reproductive complica...

Tranexamic acid is an antifibrinolytic agent that inhibits plasminogen activation, preventing clot breakdown. It's used to reduce bleeding in trauma, surgery, and heavy menstrual bleeding by stabilizing existing clots.

Triglycerides are the most abundant lipids in the body, consisting of three fatty acids attached to a glycerol backbone. They serve as the primary form of stored energy and are transported in lipoproteins. Elevated triglyceride levels (>...

Salmonella is a gram-negative, facultative anaerobic bacterium that causes gastroenteritis, typhoid fever, and bacteremia. Key species include S. enteritidis and S. typhi, with transmission occurring via contaminated food/water and the f...

Guillain-Barré syndrome (GBS) is an acute, inflammatory demyelinating polyneuropathy causing ascending muscle weakness and areflexia. It's typically triggered by infections (especially Campylobacter jejuni) and involves molecular mimicry...

Bacterial endocarditis is a life-threatening infection of the heart valves or endocardium caused by bacterial seeding, most commonly affecting abnormal or prosthetic valves. It presents with fever, new heart murmur, and systemic embolic...

Virulence factors are specific molecules produced by pathogens that enhance their ability to cause disease by facilitating invasion, immune evasion, tissue damage, or host exploitation. These factors distinguish pathogenic from non-patho...

Waterhouse-Friderichsen syndrome is acute adrenal insufficiency caused by bilateral adrenal hemorrhage, classically associated with meningococcal sepsis. It presents with shock, purpura, and adrenal crisis, with high mortality if untreated.

Impetigo is a superficial bacterial skin infection caused primarily by Staphylococcus aureus and Streptococcus pyogenes. It presents as honey-crusted lesions (non-bullous) or fluid-filled blisters (bullous) and is highly contagious, espe...

Myxomatous degeneration is a pathological process affecting heart valves where normal collagenous tissue is replaced by loose, gelatinous myxomatous tissue rich in glycosaminoglycans. This leads to valve thickening, redundancy, and prola...

Tamsulosin is a selective α1A-adrenergic receptor antagonist primarily used to treat benign prostatic hyperplasia (BPH) by relaxing smooth muscle in the prostate and bladder neck. It improves urinary flow and reduces BPH symptoms with mi...

Cellulitis is a bacterial infection of the deep dermis and subcutaneous tissue, most commonly caused by Streptococcus pyogenes and Staphylococcus aureus. It presents as spreading erythema, warmth, swelling, and tenderness without a defin...

Phosphoribosyl pyrophosphate (PRPP) is a key regulatory molecule in purine and pyrimidine nucleotide synthesis. It serves as the activated ribose donor in the de novo purine synthesis pathway and salvage pathways. PRPP synthetase deficie...

Metanephric mesenchyme is the embryonic tissue that gives rise to the nephrons and collecting system of the permanent kidney (metanephros). It forms around week 5 of gestation and is induced by the ureteric bud to differentiate into rena...

Total anomalous pulmonary venous return (TAPVR) is a rare congenital heart defect where all pulmonary veins drain into the right atrium or systemic venous circulation instead of the left atrium. An atrial septal defect (ASD) must be pres...

Bloody diarrhea is the passage of loose, watery stools containing visible blood, indicating inflammation or damage to the intestinal mucosa. It commonly results from infectious enterocolitis, inflammatory bowel disease, or ischemic colit...