CVS session 5- The Peripheral Circulation Flashcards
Does blood flow into the arteries during diastole?
No. (Just systole remember!)
What is cardiac output the product of?
Stroke volume X Heart rate
What adjective describes blood flow?
Pulsatile
Why does flow continue through arterioles in diastole?
Because artery walls recoil.
What is systolic pressure?
The arterial pressure reached during systole. (Pressure at a max here)
What is diastolic pressure?
The arterial pressure during diastole. (At a min here)
What are the typical values for systolic and diastolic pressure?
Systolic= 120mmHg Diastolic= 80mmHg
What factors increase systolic pressure? (3)
- harder heart pumping
- increased peripheral resistance
- decreased stretchiness (compliance) of arteries
Why does systolic pressure increase with age?
Artery walls become less stretchy.
Factors affecting diastolic pressure (2)
- systolic pressure
- total peripheral resistance
What is pulse pressure, and what is its typical value?
Systolic pressure - diastolic pressure
40mmHg
What are pre-capillary sphincters and what do they do?
- they are smooth muscle rings at the arterioles end of capillaries.
- they ensure that the right amount of blood gets to the right parts of us by opening and closing.
What is vasomotor tone?
The tonic (ongoing) contraction of smooth muscle in vessels.
What is vasoconstriction?
What is its relationship to resistance?
- increased contraction of the smooth muscle in vessels cause the lumen to narrow.
- increases resistance to flow.
What is reactive hyperaemia?
When blood supply is cut off to a body part and is then restored, there is an enormous increase in flow for a short while.
