acute cardiovascular response to exercise Flashcards
(106 cards)
three factors regulating venous return during exercise
- constriction of the veins (venoconstriction)
-pumping action of contracting skeletal muscle (muscle pump) - pumping action for the respiratory system (respiratory pump)
what is Cardiac output (Q)
- the amount of blood pumped by the heart each minute
at rest CO should be at?
during exercise?
- 5L per/min at rest
- 20-35 L/min during exercising
Components of CO
- product of HR and SV
stroke volume is the volume of
blood ejected with each heartbeat
another variable that affects SV is
aortic pressure (MAP)
if you have an increase of mean arterial pressure, what happens to stroke volume?
decrease
final factor that influxes stroke volume is the effect of circulating
- catecholamine (N/NE)
- direct sympathetic stimulation of the heart by cardiac accelerator nerves
overall, what three factors affect CO
- EDV
- Cardiac contractility
- cardiac after load (aortic blood pressure)
increase of CA influx into the myocardial cell would cause?
cardiac contractility
increase in cardiac afterload results in a
decrease in stroke volume
Factos affecting cardiac rate
- parasympathetic
- sympathetic nerves
factors affecting stroke volume
- sympathetic nerves
- frank starling
- EDV
- MAP
blood flow is
the change of pressure over resistance
what happens to blood flow when vascular resistance increase
blood flow decrease
blood flow can be increased by
- increase in blood pressure
- decrease in resistance
regulation of HR - PSNS
- via vagus nerve
- slows HR
- decreases contractility of the myocardium indirectly by inhibiting SNS
regulation of HR - SNS
- via cardiac accelerator nerves
- increases HR by stimulation SA and AV node
- increases contractility of the myocardium directly
Cardiovascular control center is in the
medulla oblongata
medulla oblongata consists of 4 areas
- pressor area (vasoconstrictor)
- depressor area (vasodilator)
- cardiac acceleration
- cardiac inhibitory center
increased oxygen delivery to exercising skeletal muscle is accomplished via two mechanism
- increase in CO
- redistribution of blood flow form inactive organs to the working skeletal muscle
Fick Equation
VO2 = Q x (a-VO2diff)
during exercise, blood flow to contracting muscle is increased, and blood flow to less active tissues is
reduced
auto regulation refers to
intrinsic control of blood flow by increases in local metabolites