Circulatory System Flashcards
blood flows in – loops
unidirectional
one loops is the – which moves blood from the heart, through the body, and back to heart
systemic circuit
the loops that moves blood from the heart, to the lungs, and back to the heart
pulmonary circuit
– are large blood vessels that leave the heart
arteries
arteries have thick walls and are very – to accommodate blood pressure
elastic
as arteries leave the heart, they branch into smaller vessels called –
arterioles
smallest vessels
capillaries
– site of gas exchange within tissues
capillary beds
T/F: capillary beds are so small that RBC line up single file to pass through them
true
once gas has been exchanged, the capillaries widen and become – that head back to the heart
venules
– pushes blood through arteries and arterioles
blood pressure
movement of blood in venules and veins is facilitated by muscles that contract to push the blood along and – that close to proven back flow of blood
valves
vasoconstriction and vasodilation of arteries serves as a means to regulate blood flow, pressure, and –
temperature
arteries of the systemic circuit branch off the – side of the heart and carry oxygenated blood to the capillaries of the body where gas exchange occurs
left
as the blood is being moved from the arteries to the capillaries, there is a significant – in velocity
decrease
because there are very many capillaries throughout the body, the total cross-sectional area of the capillaries is – than that of the arteries
greater
decrease in velocity provides adequate time fro gas exchange between the blood and –
interstitial fluid (fluid that surrounds cells)
deoxygenated blood returns to the – side of the heart via systemic veins
right
pulmonary circuit involves pulmonary arteries that branch off the – side o the heart and carry deoxygenated blood towards the lungs
right
– allow for gas exchange with the alveoli
pulmonary capillaries
newly oxygenated blood moves back toward the – side of the heart via pulmonary veins
left
capillary bed is a collection of capillaries, all branching off a single – , that serves a specific location in the body
arteriole
blood entering the systemic capillary bed is – and high in nutrients
oxygenated
as blood moves through the capillary bed, oxygen and nutrients must diffuse out into the – and CO2 and wastes must diffuse in
interstitial fluid
in pulmonary circulation, – enters the pulmonary capillary bed, were CO2 diffuses out and oxygen diffuses in causing oxygenation of blood
deoxygenated blood
– guard the entrance to capillary beds
precapillary sphincters
