Function of heart valves Flashcards
Which valves are of semilunar shape?
Aortic and pulmonary valves
Tricuspid valve?
Right AV valve
Bicuspid valve?
Left AV valve
Function of heart valves?
Ensures that blood flows in the right direction and prevents backflow. One way door.
What produces heart sounds?
Closing of the heart valves and the blood flowing towards the closed valve.
AIMS?
Demonstration of valve mechanisms and valve action
Valve function under systola?
Contraction of ventricles–>AV valves are closed, semilunar valves are open.
Valve function under diastola?
Relaxation of ventricles–> AV valves are open, semilunar valves are closed. Chordae tendineae and papillary muscles are relaxed.
Why is there no need for valves between atria and veins?
Because backflow usually does not occur due to similar pressure in atrium and veins. Site where venae cava enters the atrium is partially compressed during systola of atria.
What is VHD?
Valvular Heart Disease –> cardiac dysfunction, deteriation of valve function, heart can not maintain adequate circulatory flow.
What is auscultation?
Auscultation is the term for listening to the internal sounds of the body, usually using a stethoscope.
What is the first heart sound?
Ventricular myocardium contraction around incompressible blood and closure of atrioventricular valves. (cuspid valves)
When does the first heart sound occur?
50-70 ms after the beginning of the QRS complex of ECG.
What is the second heart sound?
closure of semilunar valves of aorta and pulmonary arteries.
When does the second heart sound occur?
At the end of the T-wave of ECG, indicates the end of the ejection phase.
What is the third heart sound?
Caused by the vibration of the ventricular walls in the beginning of the filling phase, occur during a quick blood influx in the heart.
When is the third heart sound apparent?
In children after the T wave of ECG.
How and when can the fourth heart sound be distinguished?
By phonocardiography at the end of the P wave of ECG. Occurs after atrial diastola.
Where is the best auscultation of the first heart sound?
Fifth intercostal space, left medioclavicularly (dicuspid valve)
Fourth intercostal space, left parasternally (tricuspid valve)
Where is the best auscultation of the second heart sound?
Second intercostal space; right parasternally (aortal valve) left parasternally (pulmonary valve)
What is the electronic stethoscope called?
JABES electronic stethoscope
What are the edges of the atrioventricular valves fastened by?
Thin fibrous cords –> cordae tendineae attached to the papillary muscles. Prevents the valves from being everted.
How are the semilunar valves prevented from being inverted?
By the anatomical structure and positioning of the cusps. Back surge of blood fills the cusps, keep them closed.
What are physiological murmurs?
Murmurs caused by turbulent flow between the heart chambers.
What are pathophysiological murmurs?
Can indicate stenotic valves, whisteling murmur (narrowing, blocking)
or valve insufficiency, swishy murmur.
Whisteling systolic murmur?
stenotic semilunar valves
Whisteling diastolic murmur?
Stenotic AV-valves
Swishy systolic murmur?
Insufficient AV-valves
Swishy diastolic murmur?
Insufficient semilunar valves.
