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a membranous fold in a canal or passage that prevents backward flow of material passing through it.
aortic valve a semilunar valve that separates the left ventricle and the aorta; it opens with end diastole, causing the second heart sound.
atrioventricular v's the cardiac valves between the right atrium and right ventricle (tricuspid valve) and the left atrium and left ventricle (mitral valve).
bicuspid valve mitral valve.
bicuspid aortic valve a congenital anomaly of the aortic valve, caused by incomplete separation of two of the three cusps; it is generally asymptomatic early in life but is predisposed to calcification and stenosis later on.
Braschi valve a one-way valve put into the inspiratory limb of a ventilator circuit in order to measure the intrinsic positive end-expiratory pressure.
cardiac v's valves that control flow of blood through and from the heart.
coronary valve a valve at the entrance of the coronary sinus into the right atrium.
flail mitral valve a mitral valve having a cusp that has lost its normal support (as in ruptured chordae tendineae) and flutters in the blood stream.
heart v's cardiac valves.
Heimlich valve a small one-way valve used for chest drainage, emptying into a flexible collection device; the valve prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation; it can be used in many patients instead of a traditional water seal drainage system.
ileocecal valve (ileocolic valve) the valve guarding the opening between the ileum and cecum.
mitral valve the cardiac valve between the left atrium and left ventricle, usually having two cusps (anterior and posterior). Called also bicuspid valve.
posterior urethral valve any of various types of congenital folds across the proximal part of the male urethra near the seminal colliculus, the most common cause of urethral obstruction in male infants.
pulmonary valve (pulmonic valve) the pocketlike cardiac valve that protects the orifice between the right ventricle and the pulmonary artery.
pyloric valve a prominent fold of mucous membrane at the pyloric orifice of the stomach.
thebesian valve coronary valve.
tricuspid valve the cardiac valve guarding the opening between the right atrium and right ventricle.
valve of vein (venous v's) any of the small cusps or folds found in the tunica intima of many veins, serving to prevent backflow of blood.
the valve closing the orifice between the left atrium and left ventricle of the heart; its two cusps are called anterior and posterior.
mi·tral valve(mī'trăl valv) [TA]
The valve closing the orifice between the left atrium and left ventricle of the heart; its two cusps are called anterior and posterior.
Synonym(s): bicuspid valve.
Synonym(s): bicuspid valve.
valve(valv) [L. valva, leaf of a folding door]
Any of various membranous structures in a hollow organ or passage that temporarily close to permit the flow of fluid in one direction only.
aortic valveAbbreviation: AoV
The valve at the junction of the left ventricle and the ascending aorta. It is composed of three segments (semilunar cusps) and prevents regurgitation. See: cardiac valve for illus.
Bauhin valveSee: Bauhin valve
Béraud valveSee: Béraud valve
bicuspid valveMitral valve.
Bjork-Shiley heart valve
A synthetic artificial heart valve that is no longer commercially available but remains implanted in thousands of patients. The valve has been known to fracture at its struts during use, which results in death in the majority of cases.
Any of the four valves that prevent the backflow of blood as it passes into, through, and out of the heart. In order of the entry of the venous blood into the right atrium, they are the tricuspid, pulmonary, mitral, and aortic. See: illustration
Carpentier-Edwards valveSee: Carpentier-Edwards valve.
A valve that permits fluids or gases to flow in just one direction. Check valves are used in infusion sets to prohibit backflow of fluids during intravenous therapy.
The coronary sinus valve at the entrance of the coronary sinus into the right atrium. Synonym: thebesian valve
The valve at the entrance of the inferior vena cava.
external nasal valve
The outermost opening of the nose (the alar rim).
A one-way valve used in chest tube drainage systems that allows fluids or gases to flow out of the chest, but does not let them reenter the bodySynonym: Heimlich flutter valve; Heimlich valve
Gerlach valveSee: Gerlach valve
high-pressure relief valve
A safety device built into a ventilator circuit that protects the patient from excessively high airway pressures by venting excess pressure into the atmosphere.
Houston valveSee: Houston valve
Huschke valveLacrimal plica.
A projection of two membranous folds of the ileum of the small intestine into the cecum of the colon. It prevents backup of fecal material into the small intestine.Synonym: valvula coli
inspiratory impedance threshold valveSee: inspiratory impedance threshold valve
internal nasal valveNasal valve.
Krause valveSee: Krause, Karl
left atrioventricular valveMitral valve.
The valve that closes the orifice between the left cardiac atrium and the left ventricle during ventricular systole.Synonym: bicuspid valve; left atrioventricular valve
The site of greatest obstruction to airflow through the nasal passages. It extends from the bony cave near the piriform aperture into part of the cartilaginous vestibule of the nose. Synonym: internal nasal valve
A safety valve that releases gas into the atmosphere from a ventilator circuit when the pressure in the circuit exceeds a known, safe level.
prosthetic heart valve
A substitute valve used to replace a diseased valve. There are two main types of prostheses: those made from biological tissues, e.g., the heart valves of animals, esp. pigs, and those made from biocompatible materials, e.g., metals or polymers. Biocompatible mechanical valves may be constructed in a variety of ways, e.g., from a ball that moves up and down in a cage; with bileaflet valves that close in the midline; or with a single leaflet (which tilts to open and close). See: illustration
The valve at the junction of the right ventricle and pulmonary artery. It is composed of three semilunar cusps and prevents regurgitation of blood from the pulmonary artery back into the right ventricle. See: cardiac valve for illus.
The prominent circular membranous fold at the pyloric orifice of the stomach. Synonym: valvula pylori
A device to reduce the pressure of gas that has been compressed in a cylinder.
right atrioventricular valveTricuspid valve.
The type of valve separating the heart and aorta and the heart and pulmonary artery. See: cardiac valve for illus.
thebesian valveCoronary valve.
tricuspid valveAbbreviation: TV
The valve that closes the orifice between the right cardiac atrium and right ventricle during ventricular systole. Synonym: right atrioventricular valve; valvula tricuspidalis See: cardiac valve for illus.
valve of VaroliusIleocecal valve.
1. a membranous fold in a canal or passage that prevents backward flow of material passing through it.
2. a mechanical device to regulate the flow of liquid or gas from an area of higher pressure to one of lower pressure.
3. automatic valve which maintains a steady vacuum in the system of a mechanical milking machine.
Adam's pressure reducing valve
see reducing valve (below).
see aortic valve.
the valves between the right atrium and right ventricle (tricuspid valve) and the left atrium and left ventricle (mitral valve).
a valve at entrance of the coronary sinus into right atrium.
a cardiac valve having a cusp that has lost its normal support (as in ruptured chordae tendineae) and flutters in the bloodstream.
ileocecal valve, ileocolic valve
see ileocecal valve.
in anesthetic circuits, it prevents exhaled gas from returning to the patient.
regulates the amount of venous blood entering the kidney.
pressure reducing valve
see reducing valve (below).
a prominent fold of mucous membrane at the pyloric orifice of the stomach.
a special valve used on anesthetic machines and which reduces the pressure of the gas reaching the exit valve so that control of the flow is made easier. Called also regulator.
valves made up of semilunar segments or cusps (valvulae semilunares), guarding the entrances into the aorta and pulmonary artery.
a thermionic diode that permits the flow of electric current in an x-ray machine in only one direction.