CH 34 Hemodynamics Flashcards
components of circulatory system
- arteries
- arterioles
- capillaries
- venules
- veins
distribution of blood
9% pulmonary circulation
7% heart
84% systemic circulation
what makes blood flow?
force that drives flow is greater than resistance
how does blood get back to heart?
by resistance
cardiac output
HR X SV
Heart rate controlled by
autonomic nervous system
SV
controlled by
- myocardial contractility
- cardiac afterload
- cardiac preload
preload
end diastolic volume/pressure
afterload
arterial pressure that LV must overcome to eject blood
CONTROL OF STROKE VOLUME IS BY
VENOUS RETURN
venous return is primary determinant of SV and therefore CO
factors that determine venous return
Systemic filling pressure
Auxiliary muscle pumps
Resistance to flow between peripheral vessels and the right atrium
Right atrial pressure
arterial pressure
peripheral resistance x CO
arterial pressure regulated by
- ans
- renin-angiotensin system
- kidneys
steady state control by ANS
regulates AP by adjusting CO and peripheral resistance
rapid control by ANS- baroreceptor reflex
Constriction of nearly all arterioles
Constriction of veins
Acceleration of heart rate
renin-angiotensin-aldosterone system
Constriction of arterioles and veins (angiotensin II)
Retention of water by the kidney (aldosterone) through the retention of sodium
natriuretic peptides
Protect the cardiovascular system in the event of volume overload
Reducing blood volume
Promoting dilation of arterioles and veins