Medical Terminology
Glossary
Pacinian corpuscle - oval pressure receptor located in subcutaneous tissue and consisting of concentric layers of connective tissue wrapped around an afferent nerve fiber; also called a lamellated corpuscle
Paget's disease - disorder characterized by a greatly accelerated remodeling process; osteoclastic resorption is massive and new bone formation by osteoblasts is extensive, resulting in irregular thickening and softening of the bones
palate - the horizontal structure separating the oral and the nasal cavities; the roof of the mouth
palliative - serving to relieve or alleviate without curing
palpate - to examine by touch; to feel
palpitation - a fluttering of the heart or an abnormal rate or rhythm of the heart
pancreas - a soft, oblong organ lying along the greater curvature of the stomach and connected by a duct to the duodenum; it has both exocrine (pancreatic juice) and endocrine (insulin, glucagon, and somatostatin) secretions
pancreatic duct - a single large tube, LETTERing with the common bile duct from the liver and the gallbladder and draining pancreatic juice into the duodenum at the hepatopancreatic ampulla (ampulla of Vater); also called the duct of Wirsung
Papanicolaou test - a cytological staining test for detection and diagnosis of premalignant/malignant conditions of the female genital tract; epithelial cells scraped from the tract are smeared, fixed, stained, and examined microscopically; also called a Pap smear
papilla - a small nipple-shaped projection or elevation
paracrine - local hormone, such as histamine, that acts on neighboring cells
paralysis - loss or impairment of motor function due to a lesion of nervous or muscular origin
paranasal sinus - a mucus-lined air cavity in a skull bone; communicates with the nasal cavity; the paranasal sinuses are located in the frontal, maxillary, ethmoid, and spenoid bones
paraplegia - paralysis of both lower extremities
parasympathetic division - one subdivision of the autonomic nervous system; preganglionic cell bodies are in brain stem nuclei & lateral gray matter of the sacral spinal cord; it is concerned with activities conserving/restoring body energy; also called the craniosacral division
parathyroid gland - one of four small endocrine glands, embedded on the posterior surfaces of the lateral lobes of the thyroid gland
paraurethral gland - mucous gland embedded in the wall of the urethra; its duct opens on either side of the urethral orifice; also called Skene's gland
parenchyma - the functional parts of any organ, as opposed to tissue that forms its stroma or framework
parenteral - situated or occurring outside the intestines; referring to introduction of substances into the body other than by way of the intestines, such as intradermal, subcutaneous, intramuscular, intravenous, or intraspinal
parietal pleura - the outer layer of serous pleural membrane; encloses & protects the lungs; the layer that is attached to the wall of the pleural cavity
parotid gland - one of the paired salivary glands located inferior and anterior to the ears; connected to the oral cavity via a duct (Stensen's) that opens on the inside of the cheek opposite the upper second molar tooth
paroxysm - a sudden periodic attack or recurrence of symptoms of a disease
parturition - the act of giving birth to young; childbirth; delivery
patellar reflex - the extension of the leg by contraction of the quadriceps femoris muscle in response to tapping on the patellar ligament; also called the knee jerk
pathogen - any disease-producing organism
pathogenesis - the development of disease or a morbid or pathological state
pathological - pertaining to or caused by disease
pectinate muscles - projecting muscle bundles of the anterior atrial walls and lining of the auricles
pectoral - pertaining to the chest or breast
pediatrician - a physician specializing in the care and treatment of children and their illnesses
pedicel - a footlike structure, as on podocytes of a glomerulus
pelvic cavity - inferior portion of the abdominopelvic cavity, containing the urinary bladder, sigmoid colon, rectum, and internal female and male reproductive structures
pelvic splanchnic nerves - preganglionic parasympathetic fibers from the levels of S2, S3, and S4 that supply the urinary bladder, reproductive organs, and the descending and sigmoid colon and rectum
pelvimetry - measurement of the size of the inlet and outlet of the birth canal
penis - the male copulatory organ, used to introduce spermatozoa into the vagina of the female
percussion - act of striking (percussing) an underlying part of the body using short, sharp blows; aids in diagnosing the part by the quality of the sound produced
pericardial cavity - small potential space between the visceral and parietal layers of the serous pericardium; contains pericardial fluid
pericardium - a loose-fitting membrane that encloses the heart; it consists of an outer fibrous layer and an inner serous layer
perichrondrium - the membrane that covers cartilage
perikaryon - the nerve cell body; it contains the nucleus and other organelles
perilymph - fluid contained between the bony and membranous labyrinths of the inner ear
perimetrium - the serosa of the uterus
perimysium - an invagination of the epimysium, dividing muscles into bundles
perineum - the pelvic floor; the space between the anus and the scrotum in the male and between the anus and the vulva in the female
perineurium - connective tissue wrapping around fascicles in a nerve
periodontal disease - a collective term for conditions characterized by degeneration of gingivae, alveolar bone, periodontal ligament, and cementum
periosteum - membrane that covers bone and consists of connective tissue, osteoprogenitor cells, and osteoblasts; it is essential for bone growth, repair, and nutrition
peripheral - located on the outer part or a surface of the body
periphery - outer part or a surface of the body; part away from the center
peristalsis - successive muscular contractions along the wall of a hollow, muscular structure
peritoneum - largest serous membrane of the body; it lines the abdominal cavity and covers the viscera
peritonitis - inflammation of the peritoneum
permissive effect - an hormonal interaction in which target cell response to one hormone is enhanced by prior or simultaneous exposure to (an)other hormone(s); endometrial maturation by progesterone, following an exposure to estrogen, is an example
pernicious - fatal
peroxisome - organelle similar in structure to a lysosome; it contains enzymes involved in hydrogen peroxide metabolism; it is abundant in liver cells
Peyer's patches - aggregated lymph nodules that are most abundant in the ileum; also called aggregated lymphatic follicles
phagocytosis - the process by which cells (phagocytes) ingest particulate matter; especially ingestion and destruction of microbes, cell debris, and other foreign matter
phalanx - the bone of a finger or toe; plural, phalanges
pharmacology - science that deals with the effects and uses of drugs in the treatment of disease
pharynx - the throat; tube that starts at the internal nares and runs partway down the neck, where it opens into the esophagus posteriorly and the larynx anteriorly
phenotype - the observable expression of genotype; physical characteristics of an organism, determined by the genetic makeup and influenced by interactions between genes and internal and external environmental factors
phenylketonuria (PKU) - a disorder characterized by elevated levels of the amino acid phenylalanine in the blood
pheochromocytoma - a tumor of the chromaffin cells of the adrenal medulla; results in hypersecretion of medullary hormones
phlebitis - inflammation of a vein, usually in the lower extremities
phlebotomy - cutting of a vein to allow the escape of blood
phosphocreatine - a high-energy molecule in skeletal muscle fibers (cells); phosphocreatine breaks down into creatine, phosphate, and energy; the energy is used to generate ATP from ADP
phospholipid bilayer - the arrangement of phospholipid molecules in two parallel rows, in which the hydrophilic heads face outward & the hydrophobic tails face inward
phosphorylation - the addition of a phosphate group to a chemical compound; the types include substrate-level, oxidative, and photophosphorylation
physiology - science that deals with the functions of an organism or its parts
pia mater - inner membrane (meninx), covering the brain and the spinal cord
piezoelectric effect - a response of bone, mainly collagen, to stress; very minute currents of electricity are produced and they are believed to stimulate osteoblasts to make new bone cells
pilonidal - denoting a growth of hairs, resembling a tuft, inside a cyst or a sinus
pineal gland - a cone-shaped gland located in the roof of the third ventricle; also called the epiphysis cerebri
pinealocyte - secretory cell of the pineal gland; produces hormones
pinna - the projecting part of the external ear, composed of elastic cartilage and covered by skin; shaped like the flared end of a trumpet; also called the auricle
pinocytosis - the process by which cells ingest liquid
pituicyte - supporting cell of the posterior lobe of the pituitary gland
pituitary dwarfism - condition caused by hyposecretion of human growth hormone (hGH) during the growth years and characterized by childlike physical traits in an adult
placenta - special structure through which exchange of materials between fetal and maternal circulations occurs; also called the afterbirth
plantar flexion - bending the foot in the direction of the plantar surface (sole)
plaque - any cholesterol-containing mass in the tunica media of arteries; a mass of bacterial cells, dextran (polysaccharide), and other debris that adheres to teeth
plasma - extracellular fluid found in blood vessels; blood minus the formed elements
plasmapheresis - procedure in which blood is withdrawn from the body, its components are selectively separated, undesireable components (e.g., toxins, metabolic substances, and antibodies) causing disease are removed, and the remainder is returned to the body
pleura - the serous membrane that covers the lungs and lines the walls of the chest and diaphragm
plexus - a network of nerves, veins, or lymphatic vessels
pluripotent hematopoietic stem cell - immature stem cell in bone marrow that gives rise to precursors of all the different mature blood cells; also called a hemocytoblast
pneumonia - acute infection or inflammation of the alveoli of the lungs
pneumotaxic area - portion of the respiratory center in the pons; it sends inhibitory nerve impulses continually to the inspiratory area to limit inspiration and to facilitate expiration
podiatry - diagnosis and treatment of foot disorders
poliomyelitis - a viral infection marked by fever, headache, stiff neck and back, deep muscle pain and weakness, and loss of certain somatic reflexes; a serious form, bulbar polio, results in destruction of motor neurons in anterior horns of the spinal nerves, leading to paralysis
polycythemia - disorder characterized by hematocrit above normal level of 55; hypertension, thrombosis, & hemorrhage occur
polyp - a tumor on a stem, especially on a mucous membrane
polysaccharides - carbohydrates in which 3 or more monosaccharides are joined chemically
polyuria - an excessive production of urine
pons - portion of the brain stem that forms a bridge between the medulla and the midbrain, anterior to the cerebellum
posterior - nearer to or at the back of the body; also called dorsal
postganglionic neuron - the second visceral motor neuron in an autonomic pathway, having its cell body and dendrites located in an autonomic ganglion and its unmyelinated axon ending at cardiac muscle, smooth muscle, or a gland
postpartum - after parturition; occurring after the delivery of a baby
postsynaptic neuron - the nerve cell that is activated by release of a neurotransmitter substance from another neuron and carries nerve impulses away from the synapse
preeclampsia - syndrome during pregnancy characterized by sudden hypertension, excessive amounts of protein in the urine, and generalized edema; it might be related to an autoimmune or allergic reaction because of the presence of a fetus
preganglionic neuron - the first visceral efferent neuron in an autonomic pathway; its cell body and dendrites are in the brain or spinal cord and its myelinated axon synapses with a postganglionic neuron in an autonomic ganglion
premonitory - giving previous warning, as premonitory symptoms
prepuce - loose-fitting skin covering the glans of the penis or clitoris; also called the foreskin
presbyopia - a loss of elasticity of the lens of the eye due to advancing age, with resulting inability to focus clearly on near objects
presynaptic inhibition - inhibition of a nerve impulse before it reaches a synapse; neurotransmitter released by the inhibitory neuron depresses release of excitatory transmitter at the excitatory neuron
prevertebral ganglion - a cluster of cell bodies of postganglionic sympathetic neurons, anterior to the spinal column and close to large abdominal arteries; also called a collateral ganglion
primigravida - a woman pregnant for the first time
primordial - existing first; especially the primordial egg cells in the ovary
proctology - the branch of medicine that treats the rectum and its disorders
progeny - offspring or descendants
progesterone (PROG) - a female sex hormone produced by the ovaries; it matures cells of the uterine endometrium and the mammary glands during the luteal phase of a menstrual cycle
prognosis - a forecast of the probable results of a disorder; the outlook for recovery
projection - the process by which the brain refers sensations to their point of stimulation
prolactin (PRL) - a hormone secreted by the adenohypophysis (anterior lobe) of the pituitary gland; initiates and maintains milk secretion by the mammary glands
prolapse - a dropping or falling down of an organ, especially the uterus or the rectum
proliferation - the rapid and repeated production of new parts, especially cells
pronation - a movement of the forearm in which the palm of the hand is turned posteriorly or inferiorly
properdin - a protein found in serum capable of destroying bacteria and viruses
prophase - the first stage of mitosis during which the chromatid pairs form and aggregate around the equatorial region of the cell
proprioception - the receipt of information from muscles, tendons, and the labyrinth, enabling the brain to determine movements and to position the body and its parts; also called kinesthesia
proprioceptor - a receptor located in muscles, tendons, or joints; it provides information about body position and movements
prostaglandin (PG) - membrane-associated lipid composed of 20-carbon fatty acids, with 5 carbon atoms joined to form a cyclopentane ring; it is synthesized in small quantities and, basically, mimics the activities of hormones
prostate gland - the doughnut-shaped gland inferior to the male urinary bladder; it surrounds the upper part of the urethra and it secretes a slightly acid solution that contributes to sperm motility and viability
prostatectomy - surgical removal of part of the prostate gland or surgical removal of the entire prostate gland
prosthesis - artificial device to replace a missing body part
prothrombin - an inactive protein synthesized by the liver, released into the blood, and converted to active thrombin in the process of blood clotting
proto-oncogene - gene responsible for some aspect of normal growth and development; it may be transformed into an oncogene, a gene capable of causing cancer
protraction - movement of the mandible or shoulder girdle forward on a plane parallel with the ground
proximal - nearer the attachment of an extremity to the trunk or a structure; nearer to the point of origin
pruritis - itching
pseudopods - temporary, protruding projections of cytoplasm
psoriasis - chronic disease of the skin, characterized by reddish plaques or papules covered with scales
psychosomatic - pertaining to the relation between mind and body; commonly used to refer to those physiological disorders thought to be caused, entirely or partly, by emotional disturbances
pterygopalatine ganglion - a cluster of cell bodies of parasympathetic post-ganglionic neurons, ending at the lacrimal and nasal glands
ptosis - drooping, as of the eyelid or the kidney
puberty - time of life during which the secondary sex characteristics begin to appear and capability for sexual reproduction is developed; usually between the ages of 10 and 17
puerperium - state immediately after childbirth, usually 4-6 weeks
pulmonary - concerning or affected by the lungs
punctate distribution - unequal distribution of cutaneous receptors
pyelitis - inflammation of the kidney pelvis and its calyces
pyemia - infection of the blood, with multiple abscesses, caused by pus-forming organisms
pyloric sphincter - a thickened ring of smooth muscle through which the pylorus of the stomach communicates with the duodenum; also called the pyloric valve
pyogenesis - the formation of pus
pyorrhea - a discharge of flow of pus, especially in the alveoli (sockets) and the tissues of the gums
pyramid - a pointed or cone-shaped structure; in the CNS, 1 of 2 triangular structures on the ventral medulla, comprising the largest motor tracts from cerebral cortex to spinal cord; triangular renal medullary structure comprising straight segments of renal tubules
pyramidal pathways - collections of motor nerve fibers arising in the brain and passing down through the spinal cord to motor cells in the anterior horns
pyrexia - a condition in which temperature is above normal
pyuria - presence of leucocytes and other components of pus in urine
