CARDIOVASCULAR SYSTEM
HEART
MACROSCOPIC IDENTIFICATION OF
VALVES
- the four valves of the heart are:
- pulmonary valve and aortic valve
- atrioventricular valves (mitral and tricuspid)
- tricuspid valve: (right atrioventricular valve)
- has 3 cusps from the papillary muscles
- prevents backflow from right ventricle to right
atrium
- (tricuspid sound is between costal cartilages 5
and 6 just left of sternum)
- pulmonary valve
- prevents backflow from pulmonary artery to right
ventricle
- located at: costal cartilage 3 (yet pulmonary
sound is between costal cartilages 2 and 3 just
left of sternum)
- consists of 3 semilunar cusps
- mitral valve (left atrioventricular valve):
- has 2 cusps from papillary muscles
- prevents backflow of blood from left ventricle to
left atrium
- (mitral sound is between costal cartilages 4 and
5 at left midclavicular line)
- aortic valve:
- prevents backflow from aorta into left ventricle
- has 3 semilunar cusps
- (aortic sound is heart between costal cartilages
2 and 3 just right of sternum)
- PULMONARY VALVE STENOSIS
- cusps of pulmonary valve a fused together,
forming a narrow central opening -->
obstruction of blood flow --> right ventricle
hypertrophy
- PULMONARY VALVE INCOMPETENCE
- if the valves become inflexible due to disease,
they will not close completely, and hence blood
flows back into right ventricle --> heart
murmur or bruit
- DISEASE OF MITRAL VALVE
- (sometimes caused by rheumatic fever)
- nodules form on valve cusps which roughens them
--> irregular blood flow
- incompetence: later, diseased cusps undergo
scarring and shortening, resulting in valvular
incompetence, hence heart murmur
- stenosis: still later, further scurring results
in progressive narrowing of orifice --> build
up of blood in left atrium and pulmonary system
--> pulmonary congestion
- AORTIC VALVE STENOSIS
- can be congenital
- stenosis --> extra work on left ventricle
-> hypertrophy of left ventricle
- heart murmurs also heard
- incompetence can also occur
