circulation:circulatory system Flashcards
whats the difference between the pulmonary and systematic circuit
pulmonary carries blood from heart to lungs and back. systematic carries blood from heart to body and back.
what are arteries and what are the walls made of
blood vessels that carry blood away from the heart. walls are thick and contain a layer of smooth muscle bc it is pumped under pressure
what do we feel when we take our pulse?
expansion of the cell wall
what controls blood flow through arteries
the autonomic nervous system and hormones
precapillary sphincters
regulate the movement of blood from the arterioles into capillaries
vasoconstriction and vasodilation
vasoconstriction is the narrowing of blood vessels. vasodilation is the widening of blood vessels
what are veins and what are the walls made out of
veins are blood vessels that carry blood towards the heart. walls contain a layer of smooth muscle, like arteries, but are way thinner bc there’s less pressure
how does blood travel back to the heart
from the capillaries to the venuoles, then to the veins and then the vena cava (by skeletal muscle action)
varicose veins
when valves (what prevents blood backflow) fail/break down and gravity will cause blood to pool towards the feet
what are capillaries and describe the walls
microscopic blood vessels that link arterioles to venules. site of gas exchange. walls are one cell thick and only one blood cell can pass at a time
why are there more veins than arteries
bc blood in arteries are under greater pressure than in veins, so the heart needs to receive an adequate blood supply from both the veins and arteries
diastole vs systole
diastole is when the heart is relaxed (blood flows in) and systole is when the heart contracts (pushing the blood out
lub vs dub
lub=av valves closing (contraction)
dub=semilunar valves closing (relaxation)
sinoatrial node
a specialized bundle of nerves that acts as a pacemaker for the heart. signals from the nervous system cause the cardiac pacemaker to increase or decrease heart rate
electrocardiogram
an ECG is a recording of the electrical charges that occur in the myocardium during the cardiac cycle
