overview of the function of the CVS Flashcards
what are the functions of the CVS?
it is a bulk flow system that transports: O2 and CO2, nutrients, metabolites, hormones, heat
in what ways is the CVS flexible?
heart can vary output
vessels can redirect blood
vessels can store blood
what is the normal cardiac output?
5L per minute
what is the maximum cardiac output of the heart?
30L per minute
when might blood be redirected?
during exercise when the skeletal muscles require more oxygen and so more blood
are the left and right sides of the heart in series or parallel?
series
given that the left and right side of the heart are in series what does this mean about ouput on each side?
it must be equal
are most vascular beds in series or parallel with the heart?
parallel
why are most vascular beds in parallel?
- so all tissues receive oxygenated blood
- allows regional direction of blood
why are the hypothalamus and anterior pituitary gland not in parallel?
so that hormones released by the hypothalamus are not diluted before the reach the anterior pituitary gland
why are the gut and liver capillary beds in series?
so that nutrient and products of digestion can be processed by the liver before they reach the rest of the body
generally what is the relationship between percentage of cardiac output to organs and % oxygen consumption of organs?
they are about equal
why is % cardiac output and %O2 consumption not equal in the kidneys?
%cardiac output is much higher as blood has to pass through the kidneys to be filtered
why is % cardiac output and %O2 consumption not equal in the skin?
%cardiac output is much higher than % O2 consumption, this is because blood has to travel to the skin to warm the peripheries
is % cardiac output to the heart equal to its %O2 consumption ?
no % O2 consumption is much higher
what is the equation for flow in the CVS?
flow= difference in pressure/resistance
what is altered to alter flow?
the resistance of blood vessels, this is done by altering radius of vessels
what is the pressure difference in the CVS?
Mean Arterial Pressure –
Central Venous Pressure
which vessels control the resistance of vascular beds?
arterioles
describe the vessels of the systemic CVS starting at the left side of the heart
- aorta
- arteries
- arterioles
- capillaries
- venules
- veins
why does the aorta have an elastic wall?
to store energy during the contraction of the heart and use it to pump blood while the heart is relaxing
what type of artery is the aorta?
elastic artery
what is the name of the non-elastic arteries?
muscular arteries
what is the structure and function of he muscular arteries?
wide lumen and strong non-elastic wall. They act as the low resistance conduit to transport blood to the peripheries as easily a possible
what is the structure and function of arterioles?
narrow lumen and thick contractile wall. Allows control of resistamce and therefore flow, this allows regional redirection of blood
describe the structure and function of capillaries?
narrow lumen and thin, single celled endothelial wall
what are the capacitance vessels and why are they called this?
venules and veins. so called as like a capacitor stores current the capacitance vessels store blood.
what is the structure of the capacitance vessels?
wide lumen, distensible, so they are a low resisitance conduit
what is the capacitance vessels function during exercise?
the blood stored in these vessels can be utilised during exercise
what separates the two sides of the heart?
interventricular septum
what is the myocardium?
the muscle that makes up the wall of the heart
what are the atriums?
the chambers that receive blood
what are the ventricles?
the chambers that pump blood
what is the aorta?
main artery, leaves the left side of the heart
what are the vena cavae?
superior and inferior. receive deoxygenated blood form the superior and inferior of the body respectively
what is the pulmonary trunk?
the portion of the pulmonary artery before it bifurcates
what are the pulmonary veins?
vessels taking oxygenated blood from the lungs to the left atrium of the heart
what is the aortic valve?
valve between left ventricle and aorta
what is the pulmonary valve?
valve between the right ventricle and the pulmonary artery
what is the mitral valve?
the valve between the left atrium and ventricle, has two “flaps”
what is the tricuspid valve?
the valve between the right atrium and ventricle has three “flaps”
what are the chordae tendinae?
cord-like tendons that connect the mitral and tricuspid valves to the myocardium
what are the papillary muscles of the heart?
attached to the chordae tendinae, they’re function is to keep the chordae tendinae tight
what are the functions of the tricuspid and mitral valves?
prevent blood moving back into the atriums of the heart while the ventricles condract
what is the function of the chordae tendinae?
prevent the tricuspid and mitral valves inverting and allow backflow of blood
