Download Physiology Objectives 8

Physiology Objectives 8
1.
Function of the heart: to pump blood to the body
2.
ECG events with:
a.
Left atrium:
b.
Left ventricle:
c.
Aorta:
3.
Normal values of:
a.
Left ventricular end-diastolic volume: 120 mL
b.
Left ventricular end-diastolic pressure: 10 mmHg
c.
Left ventricular end-systolic volume: 50 mL
d.
Left ventricular peak systolic pressure: 120 mmHg
e.
Left ventricular stroke volume: 70 mL
f.
Right ventricular end-diastolic volume: 120 mL
g.
Right ventricular end-diastolic pressure: 2 mmHg
h.
Right ventricular end-systolic volume: 50 mL
i.
Right ventricular peak systolic pressure: 25 mmHg
j.
Right ventricular stroke volume: 70 mL
k.
Aortic diastolic pressure: 80 mmHg
l.
Aortic systolic pressure: 120 mmHg
m.
Aortic pulse pressure: 40 mmHg (ASP – ADP or 120 – 80)
n.
Pulmonary artery diastolic pressure: 10 mmHg
o.
Pulmonary artery systolic pressure: 25 mmHg
4.
Right vs. left through cardiac cycle:
a.
Timing: the right atrium contracts before the left atrium (SA node); the
left ventricle contracts before the right ventricle (shorter left bundle
branch; mitral valve closes before the tricuspid valve); the pulmonic valve
opens before the aortic valve (less pressure needed in the right ventricle
for a shorter time of isovolumetric contraction); the aortic valve closes
before the pulmonic valve (the left ventricular pressure falls below aortic
pressure quickly and thus closes first)
 Note: During inspiration, there is increased blood in the pulmonary
circulation; therefore, during inspiration, it takes longer for the
pulmonic valve to close. This can be noted clinically as a
physiological split in the second heart sound (two distinct heart sounds
can be heard)
b.
Pressures: the left heart has a higher pressure than the right (the left heart
has to push blood through the systemic circulation while the right heart
only has to push blood through the pulmonary circulation)
c.
Volumes: both sides of the heart will pump out the same volumes (if one
side pumped out less blood, the other side would back up causing fluid
congestion)
5.
Origin of heart sounds: heart sounds come from the closing of a valve
6.
Strategies of heart to modulate ventricular pressure:
a.
Autonomic control
b.
Contractility (sensitivity to Ca2+)