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18 terms

Heart Valves and Venous Valves

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Heart Valves
Ensure unidirectional blood flow through the heart
Atrioventricular (AV) valves
located at each atria ventricular junction
Prevent backflow into the atria when ventricles contract
Atrioventricular (AV) valves
Tricuspid valve: R AV valve
Atrioventricular (AV) valves
Mitral valve: L AV valve
Chordae tendineae
collagen cords attached to AV valve flap
Anchor AV valve cusps to papillary muscle
In their absence, flaps would be blown upward into atria upon contraction
During heart relaxation
AV valve flaps hang loosely into the ventricular chambers
During heart contraction
intraventricular pressure rises, forcing blood against the valve flaps *closes the flaps
Semilunar (SL) valves
Aortic/Pulmonary valves
Semilunar (SL) valves
Guard arteries from the ventricles aorta/pulmonary trunk
Semilunar (SL) valves
Prevent backflow into the ventricles when ventricles relax
Semilunar (SL) valves
Each valve consists of 3 cusps; Open and close in response to pressure
Semilunar (SL) valves
Ventricular contraction and increase in intraventricular pressure--> valves open, cusps flatten against their respective arterial walls; Blood flows into vessels
Semilunar (SL) valves
Ventricles relax, blood flows back toward the heart ==> valves close
Venous Valves
Form from folds of the tunica intima
Resemble semilunar heart valves
Venous Valves
Prevent blood from flowing backwards
Venous Valves
Most abundant in veins against gravity
Venous Valves
Assist in blood flow against gravity
Absent in thoracic and abdomenal cavity veins
Venous Valves
Leaky valves results in varicose veins