2,701 articles
Permanent vegetative state
Permanent vegetative state, also called chronic VS or unresponsive wakefulness syndrome, is a prognosis of irreversible wakeful unawareness after severe brain injury, declared 3 months (nontraumatic) or 12 months (traumatic) after onset.
Perrault syndrome
Perrault syndrome, also called XX gonadal dysgenesis with deafness, is a rare autosomal recessive disorder causing sensorineural hearing loss in both sexes and ovarian dysfunction in 46,XX females, caused by biallelic variants in 12 genes, mostly mitochondrial.
Persistent eustachian valve
Persistent eustachian valve (ORPHA:99120, ICD-10 Q26.8): rare congenital IVC anomaly with postnatal persistence of the eustachian valve remnant; often asymptomatic, but can cause IVC obstruction, thrombosis, endocarditis, or right-to-left shunt with patent foramen ovale.
Persistent fetal circulation
Persistent fetal circulation, also called persistent pulmonary hypertension of the newborn (PPHN), is failure of fetal-to-neonatal circulatory transition causing right-to-left shunting, cyanosis, and refractory hypoxemia in about 1–2 per 1,000 live births.
Persistent fifth aortic arch
Persistent fifth aortic arch (PFAA), double-lumen aortic arch: rare congenital anomaly from failure of the fifth embryonic arch to regress; Weinberg types A to C; associated with coarctation, interrupted arch, VSD, pulmonary atresia.
Persistent placoid maculopathy
Persistent placoid maculopathy (PPM) is a rare idiopathic bilateral chorioretinopathy with well-defined white plaque-like macular lesions, first described in 2007, most often affecting Caucasian men in their 50s and 60s.
Perspiration
Perspiration (sweating): secretion of fluid by eccrine and apocrine sweat glands for evaporative cooling; up to 4 L/hour; sweat chloride test diagnoses cystic fibrosis; hyperhidrosis is excessive sweating.
Peters anomaly
Peters anomaly (irido-corneo-trabecular dysgenesis): rare congenital anterior segment dysgenesis causing central corneal opacity with posterior stromal and Descemet defect; types I and II, FOXC1/PAX6/PITX2/CYP1B1 genes, frequent glaucoma, keratoplasty outcomes.
Petrositis
Petrositis, or petrous apicitis, is rare suppuration of the petrous apex of the temporal bone from spreading otitis media, causing Gradenigo's syndrome: otorrhea, trigeminal facial pain, and abducens palsy. Treated with broad-spectrum antibiotics, surgery if unresponsive; ICD-10 H70.2, ICD-11 AB11.2.
Peyer's patch
Peyer's patches, named for Johann Conrad Peyer (1677), are aggregated lymphoid follicles of the small intestinal gut-associated lymphoid tissue; M cells sample luminal antigens, driving IgA germinal-center responses and oral vaccine uptake.
Phalanx bone
Phalanx bone (plural phalanges): the 14 long bones of each hand and foot beyond the metacarpals and metatarsals; three per finger or toe, two in the thumb or hallux; base, shaft, head; proximal phalanx is the most commonly fractured hand bone.
Phantom limb
Phantom limb: perception that an amputated or congenitally missing limb is still present, causing phantom limb sensation (PLS) and phantom limb pain (PLP) in most amputees; mechanisms include neuromas and cortical reorganization; treatments include mirror therapy, GMI, VR, and rTMS.
Phantom pain
Phantom pain, also called phantom limb pain, is pain felt in an amputated or missing body part, affecting most amputees and often treated with mirror therapy.
Pharyngeal reflex
Pharyngeal reflex (gag reflex): involuntary throat contraction protecting the airway, mediated by CN IX afferent and CN X efferent limbs; poorly predictive of dysphagia despite traditional bedside use.
Pharynx
Pharynx (throat): funnel-shaped muscular tube from skull base to C6, shared by digestive and respiratory tracts, divided into nasopharynx, oropharynx, and laryngopharynx; constrictor muscles, vagus and glossopharyngeal innervation, pharyngeal arch embryology.
Phenylthiocarbamide
Phenylthiocarbamide (PTC, phenylthiourea), a synthetic bitter compound whose bimodal tasting ability, controlled by TAS2R38 variants, made it a classic human Mendelian trait discovered in 1931.
Phineas Gage
Phineas Gage (1823–1860), American railroad foreman whose 1848 Cavendish, Vermont tamping-iron injury caused frontal lobe damage with reported personality change; famous case in neuroscience, skull and iron at Harvard.
Phlegm
Phlegm, also called lung butter, is an unusually large amount of thick mucus produced by cells lining the upper airways and lungs, often causing coughing and chest discomfort.
Phonation
Phonation is the production of voiced sound by vibration of the vocal folds, muscular folds of mucous membrane in the larynx, as air from the lungs passes between them.
Photokeratitis
Photokeratitis (ultraviolet keratitis, arc eye, snow blindness) is a painful, usually bilateral corneal epithelial injury from UV exposure, with delayed onset 6-12 hours and self-healing within 24-72 hours.
Photoreceptor cell
Photoreceptor cells (rods and cones) are retinal neurons that convert light into electrical signals via a G-protein phototransduction cascade; rods detect single photons in dim light, cones mediate bright-light, color, high-acuity vision.
Photoreceptor disk component PRCD
PRCD (photoreceptor disc component) is a 54-amino-acid, ~6 kDa rhodopsin-binding protein of unknown function found only in photoreceptor outer segment discs; its C2Y mutation causes canine progressive rod-cone degeneration and human retinitis pigmentosa 36.
Photorefractive keratectomy
Photorefractive keratectomy (PRK) is a type of refractive surgery that uses an excimer laser to reshape the cornea, without a flap, correcting myopia, hyperopia, and astigmatism.
Phrenic nerve
Phrenic nerve (nervus phrenicus): bilateral mixed nerve from C3-C5 (mainly C4) that is the sole motor supply of the diaphragm and sensory nerve of its center, pericardium, and mediastinal pleura; injury causes hemidiaphragm paralysis.
Physiologic and autonomic bradycardia
Physiologic and autonomic bradycardia is a slow heart rate arising from normal autonomic regulation, chiefly increased parasympathetic (vagal) tone, seen during sleep, rest, and reflex states like vasovagal reactions.
Physiologic anisocoria
Physiologic anisocoria, also called simple or essential anisocoria, is benign unequal pupil size of 1 mm or less, equal in light and dark, affecting up to 20% of people and requiring no treatment.
Physiological Adaptation
Physiological adaptation (MeSH D000222) is the non-genetic biological change of an organism to environmental challenges, within one lifetime; includes acclimatization, allostasis, thermotolerance, and phenotypic plasticity, distinct from genetic adaptation.
Physiological factors
Physiological factors (R-HSA-5578768) is a Reactome human pathway on natriuretic peptide regulation of cardiovascular homeostasis, within Cardiac conduction; it covers NPPA expression, corin processing, NPR1/NPR2 binding, and sacubitril metabolism.
Physiological Phenomena
Physiological phenomena are the functions and properties of living organisms supporting life; also MeSH descriptor D010829 (tree G07), covering homeostasis, body temperature, growth, adaptation, and related processes.
Physiology & behavior
Physiology & Behavior is a peer-reviewed academic journal published by Elsevier that covers the causal physiological mechanisms of behavior; it was founded in 1966 by Pergamon Press.