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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.
valve of cor·o·nar·y si·nus[TA]
a delicate fold of endocardium at the opening of the coronary sinus into the right atrium.
Etymology: L, corona, crown, valva, folding door
a semicircular fold of endocardium that prevents backflow of blood from the right atrium into the coronary sinus.
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.