P - Glossary of Terms

[sonoedu]

pachy-	(pak'e-) Prefix meaning thick, dense; as pachypleuritis, inflammation of pleura attended with thickening of membranes.
pachycephalic	(pak"e-se-fal'ik) Having unusually thick, dense cranial walls.
Paget's disease	(paj'ets). Osteitis deformans; chronic disease of bones, characterised by irregular rarefaction and thickening, enlargement, and deformity.
pair production	The interaction between the X-ray and the nuclear electric field that causes the X-ray to disappear and causes two electrons, one positive and one negative, to take its place.
palate	(pal´at) The roof of the oral cavity.
palatine	(pal´a-t-in) Pertaining to the palate.
palmar	(pal´mar) Pertaining to the palm of the hand.
palpation	To examine by the sense of touch.
palpebra	(pal´pe-bra) An eyelid.
palpitations	Rapid or fluttering beating of the heart, of which one is aware.
palsy	(pawl'ze) Loss of power of voluntary movement or sensation, partial or complete, of any part of body; paralysis.
panchromatic	Referring to film that is sensitive to the entire visible light spectrum.
pancreas	(pan´kre-as) A mixed organ in the abdominal cavity that secretes pancreatic juices into the GI tract and insulin and glucagon into the blood.
pancreatic duct	(pan´´kre-at´ik) A drainage tube that carries pancreatic juice from the pancreas into the duodenum of the hepatopancreatic ampulla.
pancreatic islets	A cluster of cells within the pancreas that forms the endocrine portion and secretes insulin and glucagon; also called islets of Langerhans.
papillae	(pa-pil´e) Small, nipplelike projections.
papillary muscle	(pap´i-ler´´e) Muscular projections from the ventricular walls of the heart to which the chordea tendineae are attached.
para-	(par'ah) Prefix denoting the following: irregular or abnormal, as in paranoia, parachroia, parachroma; resembling in form (said of diseases), as in paraparesis, parapneumonia, paratyphoid; near, beside, alongside of, as in paracystic, parathyroid; accessory to, as in paranasal sinuses.
paracentesis	(par"ah-sen-te'sis) Surgical puncture of a cavity of body for withdrawal of fluid; tapping.
paradoxical	Seemingly contradictory or unbelievable, but which may actually be true in fact.
parallel circuit	A circuit that contains elements that bridge conductors rather than lie in a line along a conductor.
parallel grid	A simple grid in which all lead grid strips are parallel. see nxxonfocused grid.
paralysis	(pah-ral'i-sis). Loss of function or sensation, partial or complete, in any part of body through injury or disease of nerve supply; palsy.
paralysis agitans	(pah-ral'i-sis aj'i-tanz) Chronic, progressive disease of old age, characterised by muscular tremor, weakness, and peculiar gait; shaking palsy or Parkinson's disease.
paramagnetic	Referring to materials slightly attracted to a magnet and loosely influenced by an external magnetic field.
paranasal sinus	(par´´a-na´zal si´nus) An air chamber lined with a mucous membrane that communicates with the nasal cavity.
parasympathetic	(par´´a-sim´´pa-thet´ik) Pertaining to the division of the autonomic nervous system concerned with activities that, in general, inhibit or oppose the physiological effects of the sympathetic nervous system (eg relaxes us for gut tube activity (salivation, gastric activity, peristalsis, sphincter relaxation), it constricts the pupils, slows the heart, and it has important reproductive functions.) (see sympathetic)
parathyroids	(par´´a-thi´roidz) Small endocrine glands embedded on the posterior surface of the thyroid glands that are concerned with calcium metabolism.
parenchyma	(pah-reng'ki-mah) The gas-exchanging portion of the lung, consisting of alveoli and their capillaries, estimated to constitute approximately 90% of total lung volume. On a radiograph, pulmonary parenchyma appears as lung exclusive of visible pulmonary vessels and airways.
parenchymal	Referring to part of the organ that contains tissues representative of that particular organ.
paries	(pa'ri-ez) A wall, especially wall of a hollow organ or cavity.
parietal	(pa-ri´e-tal) Pertaining to a wall of an organ or cavity.
parietal pleura	(ploor´a) The thin serous membrane attached to the thoracic walls of the pleural cavity.
parotid	(pa-rot'id) Situated near ear; specifically, parotid gland, largest of salivary group, which is located on side of face in front of and below ear.
parotid gland	(pa-rot´id) One of the paired salivary glands located on the side of the face over the masseter muscle just anterior to the ear and connected to the oral cavity through a salivary duct.
parotitis	(par"ot-i'tis) Inflammation of parotid glands; mumps.
partial volume effect	Distortion of the signal intensity from a tissue because it extends partially into an adjacent slice thickness.
particle accelerator	An atom "smasher."
particulate radiation	Radiation distinct from X-rays and gamma rays; examples are alpha particles, electrons, neutrons, and protons.
parturition	(par´´tu-rish´un) The process of giving birth; childbirth.
patent	(pa'tent) Open, patulous, unoccluded: as lumen of a vessel.
patho-	(path'o-) Prefix denoting disease; as pathogenic, causing or giving origin to disease.
pathogen	(path´o-jen) Any disease-producing microorganism or substance.
pathognomonic	Specially distinctive or characteristic of a disease or pathologic condition.
pathology	(path-thol'o-je) Scientific study of essential nature of diseases, structural and functional alterations caused by them; condition or changes produced by disease.
P.C.	Abbreviation for Latin post cibum, after food.
pectoral	(pek´to-ral) Pertaining to the chest region.
pectoral girdle	The portion of the skeleton that supports the upper extremities.
pediatrics	(pe"de-at'riks) Science that treats diseases of children.
pedicle	(ped´i-k'l) The portion of a vertebra that connects and attaches the lamina to the body.
pedicular	(pe-dik'u-Iar) Pertaining to lice.
pediculate	(pe-dik'u-lat) Of or pertaining to a pedicle or pedicles.
peduncular	(pe-dung'ku-Iar) Of or pertaining to a peduncle or pedicle.
pedunculated	Having a stalk (pedicle).
pelvic	(pel´vik) Pertaining to the pelvis.
pelvic girdle	The portion of the skeleton to which the lower extremities are attached
pelvimetry	(pel-vim'e-tre) Measurement of size and capacity of pelvis.
pelvis	(pel´vis) the term pelvis can mean the bony pelvis (a basin like bony structure formed by the sacrum and ossa coxae), the pelvic part of the abdominal cavity or the renal pelvis
penetrability	The ability of an X-ray to penetrate tissue; the range in tissue; X-ray quality.
penetrometer	An aluminum step wedge.
penis	(pe´nis) (latin=tail) The male organ of copulation, used to introduce sperm into the female vagina and through which urine passes during urination.
pennate	(pen´=at) Pertaining to a skeletal muscle fibre arrangement in which the fibres are attached to tendinous slips in a featherlike pattern.
penumbra	The region of partial shadow at the periphery of the X-ray field that receives radiation from only a portion of the focal spot. Image blur result from the size of the focal spot.
pepsin	(pep´sin) The protein-digesting enzyme secreted in gastric juice.
peptic ulcer	(pep´tik ul´ser) An injury to the mucosa of the esophagus, stomach, or small intestine due to the action of acidic gastric juice.
perforating canal	A minute duct through compact bone by which blood vessels and nerves penetrate to the central canal of an osteon; also called Volkmann's canal.
peri-	(per'i-) Prefix meaning around, about, all around, near; as periapical, around the apex of a tooth.
pericardium	(per´´i-kar´de-um) A protective serous membrane that surrounds the heart.
perichondrium	(per´´i-kon´dre-um) A toughened connective sheet that covers some kinds of cartilage.
perikaryon	(per´´i-kar´e-on) The cell body of a neuron.
perilymph	(per´i-limf) A fluid of the inner ear that provides a liquid-conducting medium for the vibrations involved in hearing and the maintenance of equilibrium.
perimysium	(per´´u1-mis´e-um) Fascia (connective tissue) surrounding a bundle of muscle fibers.
perineum	(per´´1-ne´um) The floor of the pelvis, which is the region between the anus and the symphysis pubis. It is the region that contains the external genitalia.
perineurium	(per´´1-noor´e-um) Connective tissue surrounding a bundle of nerve fibers.
periodontal membrane	(per´´e-o-don´tal) A fibrous connective tissue lining the dental alveoli.
periosteum	(per´´e-os´te-um) A fibrous connective tissue covering the outer surface of bone.
peripheral nervous system	(pe-rif´er-al) The nerves and ganglia of the nervous system that lie outside of the brain and spinal cord. (PNS) This includes both the crainial nerves arising from the brain (12 pairs) and the spinal nerves arising from the spinal cord (31 pairs, usually) (see central nervous system)
periphery	(pe-rifer-e) External part of an organ; circumference.
peristalsis	(per´´i-stal´sis) Rhythmic contractions of smooth muscle in the walls of various tubular organs by which the contents are forced onward.
peritoneal cavity	Strictly speaking nothing is in the peritoneal cavity except a thin layer of peritoneal fluid. But it is used synonymously with the abdominal pelvic cavity.
peritoneum	(per´´i-to-ne´um) The serous membrane that lines the abdominal cavity and covers the abdominal visceral organs.
permanent magnet	A magnet whose magnetism is artificially induced.
permeative	Diffusely spreading through or penetrating a substance, tissue, or organ, as by a disease process such as cancer.
peroneal	(greek) can be used to mean lateral in the leg, going out of fashion (see fibular, tibial)
petrous	(pet'rus) Resembling a stone or rock; specifically, pertaining to petrosa or petrous portion of temporal bone.
pH	Symbol used to denote negative logarithm of hydrogen ion concentration in gram atoms per liter.
phalanx	(fa´langks), pl. phalanges A bone of a finger or toe.
phantom	A device that simulates some parameters of the human body for eval‎uating imaging system performance.
pharynx	(far´ingks) The organ of the digestive system and respiratory system located at the back of the oral and nasal cavities that extends to the larynx anteriorly and to the esophagus posteriorly; also called the throat.
phenidone	A secondary constituent used in the chemi¬cal composition of developing agents.
phleb-	(fleb-) Prefix denoting relation to a vein; as phlebitis, phlebolith.
phlebogram	(fleb'o-gram) Radiograph of veins following injection of radiopaque substance; also called a venogram.
phonate	(fo'nat) To utter throaty or laryngeal, usually prolonged, vowel sounds with minimum aid from lips.
phosphor	The active layer of the radiographic intensifying screen closest to the radiographic film.
phosphorescence	The emission of visible light during and after stimulation.
photoconductor	A material that conducts electrons when illuminated.
photodiode	A solid-state device that converts light into an electric current.
photodisintegration	The process by which very high energy X-rays can escape interaction with electrons and the nuclear electric field and can be absorbed directly by the nucleus.
photoelectric effect	An X-ray absorption process in which the photon interacts with a tightly bound inner shell electron of an atom. Part of the energy of the photon is used to overcome the forces binding the electron to the atom; the remainder is expressed as kinetic energy of the emitted electron (which is termed a “photoelectron”).
photoelectron	An electron that has been removed during the process of photoelectric absorption.
photoemission	Electron emission after light stimulation.
photographic effect	The formation of the latent image.
photographic density	see optical density.
photometer	An instrument that measures light intensity.
photomultiplier tube	An electron tube that converts visible light into an electrical signal.
photon	Electromagnetic radiation that has neither mass nor electric charge but interacts with matter as though it is a particle; X-rays and gamma rays.
photoreceptor	(fo´´to-re-sep´tor) A sensory nerve ending that responds to the stimulation of light.
photospot camera	A camera that exposes only one frame when active, receiving its image from the output phosphor of the image-intensifier tube.
photostimulation	The emission of visible light after excitation by laser light.
phototimer	A device that allows automatic exposure control.
phrenic	(fren'ik) (Greek - phren, phrenos, diaphragm, mind) Of or pertaining to diaphragm or to mind; phrenic nerve.
phrenico-	(fren'i-ko) Prefix signifying some relation to phrenic nerve; as phrenicotomy.
phreno-	(fren'o) Prefix denoting relation to diaphragm, as in phrenogastric, phrenohepatic, or to mind, as in phrenopathy, phrenoplegia.
physiology	(fiz´´e-ol´o-je) Scientific study of functions of tissues and organs, as distinguished from anatomy, the study of their structure.
pia mater	(pi´ua ma´ter) The innermost meninx that is in direct contact with the brain and spinal cord.
pineal gland	(pin´e-al) A small cone-shaped gland located in the roof of the third ventricle.
pinna	(pin´ua) The outer, fleshy portion of the external ear; also called the auricle.
pinocytosis	(pin´´uo-si-to´sis) Cell drinking; invagination of the cell membrane forming narrow channels that pinch off into vacuoles. This allows for cellular intake of extracellular fluid and dissolved molecules.
pitch	See spiral pitch ratio.
pituitary gland	(pi-too´i-ter-e) A small, pea-shaped endocrine gland situated on the interior surface of the diencephalonic region of the brain, consisting of anterior and posterior lobes; also called the hypophysis.
pivot joint	(piv´ot) A synovial joint in which the rounded head of one bone articulates with the depressed cup of another to permit a rotational type of movement only.
pixel	A picture element; the cell of a digital image matrix.
placenta	(pla-sen´tah) The organ of metabolic exchange between the mother and the fetus.
placentography	(plas"en-tog'ra-fe) Radiographic examination of gravid uterus for localisation of placenta.
planck's constant (h)	A fundamental physical constant that relates the energy of radiation to its frequency.
plane	(pla'n) Any flat surface, real or imaginary.
planetary rollers	Rollers positioned outside the master roller and guideshoes.
planigraphic principle	Tomographic principle in which fulcrum or axis of rotation is raised or lowered to alter level of focal plane; the tabletop height remains constant.
planigraphy	(plah-nig'ra-fe) See tomography.
plantar	(plan´tar) Pertaining to the sole of the foot.
plantarflexion	A movement at the ankle joint. Pointing toes down to the ground (flexion) (see dorsiflexion)
plasma	(plaz´ma) The fluid, extracellular portion of circulating blood.
platelets	(pl-at-letz) Small fragments of specific bone marrow cells that function in blood coagulation; also called thrombocytes.
platy-	(plat'i-) Prefix meaning broad, flat; as platycephalic, having a broad, flat head.
pleural	(ploor´al) Pertaining to the serous membranes associated with the lungs.
pleural cavity	The potential space between the visceral pleura and parietal pleura.
pleural effusion	The presence of fluid within the pleural space.
pleural membranes	Serous membranes that surround the lungs and provide protection and compartmentalization
pleural thickening	An increase in thickness of the pleura, usually resulting from prior inflammation with subsequent fibrosis or tumor. The presence of pleural thickening may be suggested when pleural opacity is stable for long periods of time on serial radiographs (usually over a period of months or years) or when the pleural opacity fails to demonstrate mobility on decubitus radiographs. Note that in the latter circumstance, loculated pleural fluid collections may behave similarly, and thus the lack of mobility of a pleural opacity with decubitus radiographs is not pathognomonic for pleural thickening.
pleurisy	(ploor'i-se). Inflammation of pleura, usually attended with exudation into pleural cavity.
plexus	(plek´sus) A network of interlaced nerves or vessels.
plexus of Auerbach	(ow´er-bak) See myenteric plexus.
plexus of Meissner	(m-is´ner) See submucosal plexus.
plica	(pli'kah) A fold; as plica sublingualis a fold of mucous membrane on each side of floor of mouth overlying the sublingual gland.
plicae circulares	(pli´ce sur-kyuu-lar´=ez) Deep folds within the wall of the small intestine that increase the absorptive surface area.
pluripotential stem cell	A stem cell that has the ability to develop into several different types of mature cells.
-pnea	(-p'ne'ah) Suffix meaning breath; as in eupnea, dyspnea.
pneumo-	(nu'mo-) Prefix denoting relation to lungs or to air or other gas: as pneumonia, pneumonic, pneumothorax, pneumocystography. pneumoperitoneum.
pneumococcus	Type of gram-positive bacteria.
pneumoconiosis	(nu"mo-ko"ne-o'sis). Condition characterised by permanent deposition of particulate matter of substantial amounts in the lungs. Deposition is usually of environmental or occupational nature.
pneumoperitoneum	Presence of free gas in the peritoneal cavity.
pneumotaxic area	(nu´´mo-tak´sik) The region of the respiratory control center located in the pons of the brain.
pneumothorax	(nu'mo-tho'raks). Accumu¬lation of air or other gas in pleural cavity, usually induced for therapeutic purposes but, occasionally spontaneously as a result of injury or disease.
Pocket ionisation chamber (pocket dosimeter)	A personnel radiation-monitoring device.
point lesion	Any change that results in the impairment or loss of function at the point of a single chemical bond.
point mutation	A molecular lesion caused by the change or loss of a base that destroys the triplet code and may not be reversible.
polarity	The existence of opposing negative and positive charges.
pole	The magnetically charged end of a material.
pollicus	Latin pollex = thumb; hence of the thumb
poly-	(pol'e-) Prefix meaning many. much, often; as polycystic, polygraph, polymorphous.
polyenergetic	Referring to radiation, such as X-rays, having a spectrum of energies.
polyp	(pol'ip) Projection of hypertrophied mucous membrane in a body cavity such as nose, paranasal sinuses and urinary bladder; a polypus.
polysaccharide	A large carbohydrate that includes starches and glycogen.
polyuria	(pol´´e-yoor´e-ua) Excretion of an excessively large volume of urine in a given period.
pons	(ponz) The portion of the brain stem just above the medulla oblongata and anterior to the cerebellum.
popliteal	(pop´´li-te´al) Pertaining to the concave region on the posterior aspect of the knee.
porus	(po'rus) Latin for pore or opening; meatus; as porus acusticus interims, internal auditory meatus.
positive beam limiting (PBL)	A feature of radiographic collimators that automatically adjusts the radiation field to the size of the image receptor.
post-	- Prefix meaning behind, after, later; as postnasal, postpartum, postdiastolic.
post cibum	(post si'bum). Latin for after food; abbreviation, p.c.
Post-primary tuberculosis (reactivation TB)	The development of tuberculosis one or more years after initial infection, usually appear ing as nodular and linear areas of increased opacity in the upper lobes, often with cavitation.
posterior	(pos-ter´i-or) Toward the back; also called dorsal.
posterior pituitary	(pi-too´it-ere) See neurohypophysis.
posterior root	An aggregation of sensory neuron fibres lying between a spinal nerve and the posterolateral aspect of the spinal cord; also called the dorsal root or sensory root.
posterior root ganglion	(gang´gle-on) A cluster of cell bodies of sensory neurons located along the posterior root of a spinal nerve
posteroanterior	(pos''ter-o-an-ter'i-er) Directed or extending from back to front.
postnatal	(p-ost-na´tal) After birth.
postpartum	After childbirth.
potassium bromide	A compound used as a restrainer in the developer.
potassium iodide	A compound used as a restrainer in the developer.
potential energy	The ability to do work by virtue of position.
power	Time rate at which work (W) is done. 1 W = 1 J/s.
power-of-10 notation	Exponential form.
pre-	(pre-) Prefix signifying before in time or place; as prenatal, prevertebral.
precurser cell	An immature cell.
predetector collimator	A collimator that restricts the X-ray beam viewed by the detector array.
prepatient collimator	A collimator that consists of several sections so that a nearly parallel X-ray beam results.
pregnancy	A condition in which a female is carrying a developing offspring within the body.
prenatal	(pre-na´tal) Pertaining to the period of offspring development during pregnancy; before birth.
prepuce	(pre´pyoos) A fold of loose, retractable skin covering the glans of the penis or clitoris; also called the foreskin.
prereading voltmeter	A kVp meter that registers even though an exposure is not being made and no current is flowing in the circuit; this allows the voltage to be monitored before an exposure.
preservative	A chemical additive, usually sodium sulfide, that maintains the chemical balance of the developer and fixer.
preventative maintenance	A planned program of parts replacement at regular intervals.
primary coil	The first coil through which the varying current in an electromagnet is passed.
primary protective barrier	Any wall to which the useful beam can be directed.
primary radiation	The radiation emitted from the X-ray tube; also, unscattered radiation.
primary tuberculosis	Direct progression of the initial infection with M. tuberculosis, usually appearing as consolidation in the lower lobes, often accompanied by hilar and mediastinal lymphadenopathy and pleural effusion.
primigravida	(pri"mi-grav'i-dah) Woman pregnant for first time.
primipara	(pri-mip'ah-rah) Woman who is bearing or has borne her first child.
pro-	(pro-) Prefix signifying forward, to front, according to; as project, progress, prolapse, proportion.
process	Latin = going forwards, used to indicate growing out, i.e., an outgrowth, usually of bone, e.g., the zygomatic process of the temporal bone.
processing	Chemical treatment of the emulsion of a radiographic film to change a latent image to a manifest image.
processing mottle	A type of mottle caused by processor problems such as dirty rollers, old chemicals, contaminated solutions, improperly mixed solutions, static discharge, etc.
processor	The electronic circuitry that does the actual computations and the memory that supports it.
procto-	(prok-to-) Prefix denoting relation to anus and rectum; as proctopolypus, proctoscope, proctitis.
prodromal period	The first stage of the acute radiation syndrome, which occurs within hours after radiation exposure.
prognosis	(prog-no'sis) Forecast of course and probable outcome of a disease.
proliferate	To multiply rapidly, increase profusely.
pronation	(pro-na´shun) A rotational movement of the forearm in which the palm of the hand is turned posteriorly. Act of lying face down; opposite of supination.
prone	(pron) Lying face down; having palm of hand facing downward or backward.
proper fraction	A fraction in which the quotient is less than 1.
prophase	The phase of cell division during which the nucleus and the chromosomes enlarge and the DNA begins to take structural form.
prophylaxis	(pro''fi-lak'sis) Protection from or prevention of disease; protective or preventive treatment.
proportion	The relation of one part to another.
proportional counter	A sensitive instruments used primarily as stationary laboratory instruments for the as say of small quantities of radioactivity.
proprioceptor	(pro´´pre-o-sep´tor) A sensory nerve ending that responds to changes in tension in a muscle or tendon.
prostate	(pros´t-ate) A walnut-shaped gland surrounding the male urethra just below the urinary bladder that secretes an additive to seminal fluid during ejaculation.
prostato-	(pros'tah-to-) Prefix denoting relation to prostate gland; as prostatocystitis, prostatitis.
prostatography	(pros"tah-tog'ra-fe) Radiographic examination of prostate gland.
prosthesis	(pros-the´sis) An artificial device to replace a diseased or worn body part.
protective coating	The layer of the radiographic intensifying screen closest to the radiographic film.
protective housing	A lead-lined metal container into which the X-ray tube is fitted.
protein synthesis	The metabolic production of proteins.
proton	An elementary particle with a positive electric charge equal to that of an electron and a mass approximately equal to that of a neutron. It is located in the nucleus of an atom.
protoplasm	(pro´to-plaz´´em) A general term for the colloidal complex of protein that constitutes the living material of a cell. It includes cytoplasm and nucleoplasm.
protracted dose	A dose of radiation delivered continuously but at a lower dose rate.
protraction	(pro-trak´shun) The movement of a body part, such as the mandible, forward on a plane parallel with the ground; the opposite of retraction.
protuberance	(pro-tu'ber-ans) Any projecting part; a swelling; general term for a process or projection.
proximal	(prok´-si-mal) Closer to the midplane of the body or to the origin of an appendage; the opposite of distal.
pseudo-	(su'do-) Prefix meaning false; illusory; having a deceptive resemblance to; as pseudoankylosis, pseudoparalysis, pseudoarthrosis.
pseudohermaphrodite	(soo´´do-her-maf´ro-dite) An individual with some of the physical characteristics of both sexes, but who lacks functioning gonads of both sexes; a true hermaphrodite has both testes and ovaries.
P.S.P	Abbreviation commonly used for a kidney function test with use of either phenolsulfonphthalein or indigo carmine.
psychiatry	(si'ki'ah-tre) Science that treats mental disorders, psychoses, and neuroses.
psycho-	(si'ko-) Prefix denoting relation to mind or mental processes, as in psychogenic, psychoneurosis, psychosis.
psychology	(si-kol'o-je) Science that deals with mind in all its aspects; study of mental activity and behavior.
ptosis	(to-sis) Prolapse, or dropping, of an organ from its normal position; usually used as a suffix, as in enteroptosis, gastroptosis, visceroptosis.
puberty	(pyoo´ber-te) The period of development in which the reproductive organs become functional.
pubis	the components of the hip bone, the ilium, ischium and pubis, meet in the centre of the acetabulum, the three parts fusing at about 16 yrs of age
puerile	(pu'er-il) Of or pertaining to a child or children or to childhood; immature; juvenile.
puerperal	(pu-er'per-al) Of or pertaining to childbirth; as puerperal sepsis, puerperal fever.
pulmonary	(pul´mo-ner´´e) Pertaining to the lungs.
pulmonary circulation	The system of blood vessels from the right ventricle of the heart to the lungs that transports deoxygenated blood and returns oxygenated blood from the lungs to the left atrium of the heart.
pulp cavity	A cavity within the center of a tooth that contains blood vessels, nerves, and lymphatics
pulse mode /rate mode	Instruments designed to detect the presence of radiation. Radiation produced in pulses instead of continuously, used in image intensifiers to decrease patient dose
punctate	Marked with dots or tiny spots.
pupil	The opening through the iris that permits light to enter the posterior cavity of the eyeball and be refracted by the lens through the vitreous chamber.
purgative	(pur'gah-tiv) Purging or strong cathartic medicine, causing extensive evacuations. These agents are more drastic in action than laxative or cathartic groups, which stimulate peristaltic activity and increase tendency to evacuate bowels with a minimum of irritation.
Purkinje fibers	(pur-kin´je) See conduction myofibers.
purulent	(pu'roo-lent) Consisting of or of nature of pus or matter; associated with suppuration; as a purulent lesion or wound.
pus	(pus) Yellowish, greenish, or brownish exudate generated by suppuration as a result of bacterial infection.
putrefaction	(pu''tre-fak'shun) Decomposition of organic (animal or vegetable) matter, with formation of various foul-smelling products; decay.
putrescent	(pu-tres'ent) Undergoing decomposition or decay; pertaining to putrefaction; as an offensive or putrescent odor.
pyelo-	(pi'e-lo) Prefix denoting relation to pelvis of kidney, as in pyelogram, pyelitis.
pyloric sphincter	(pi-lor´ik sfingk´ter) A modification of the muscularis tunic between the stomach and the duodenum that functions to regulate the food material leaving the stomach.
pylorus	Greek = gate-keeper; hence, the part of the pyloric canal containing the sphincter, which guards the opening into the duodenum; adjective - pyloric
pyo-	(pi'o-) Prefix signifying presence of pus; as pyogenesis, pyonephrosis, pyonephrosis, pyuria.
pyramid	(pir´a-mid) Any of several structures that have a pyramidal shape (e.g., the renal pyramids in the kidney and the medullary pyramids on the anterior surface of the brain).