WEEK 4 - CARDIO Pt3 Flashcards
what point of blood pressure is systole and diastole?
systole: highest blood pressure point
diastole: lowest blood pressure point
what is happens to the atrial bp?
it never gets really low and remains at a pretty constant level as it is one of the most critical factors that the body regulates (it is prioritised).
what happens if the mean aterial pressure (MAP) falls?
you get not enough blood flow to the brain and extremeties.
what is MAP?
mean arterial pressure - a balance between the blood flowing in and out of arteries which is determined by how much blood is in the arteries.
what controls the blood flow out of arteries into capillaries?
resistance of arteries.
blood in/out determines:
pressure
increased resistance =
descrease in outflow
increased output =
increase in flow
what is the equation for aterial pressure?
arterial pressure = cardiac output x total peripheral resistance.
flow =
pressure/resistance
MAP =
cardiac output x total peripheral resistance
CO =
stroke volume (L/beat)[contraction strength] x heart rate (beats/min)[contraction speed]
what is the brain vs sa node’s role in the beating of the heart?
the sa node makes the heart beat, but the brain tells it to speed up or slow down.
whats the difference between efferent and afferent?
afferent input: from systems to monitor what is happening
efferent output: instructions from brain to systems
what are baroreceptors?
blood pressure sensors - they are strentch receptors, mostly in the aortic arch.
parasympathetic:
break - rest and digest
sympathetic:
accelorator - fight or flight
to bring blood pressure down:
less input using efferent output from vagus nerve through parasympathetic system.
wdoes the vagus nerve do?
connects brain to heart at SA and AV nodes.
to bring blood pressure up:
sympathetic system through sympathetic trunk ganglion into sympathetic cardiac nerves which interact directly with SA and AV nodes (SA contracts faster, AV pause shorter).