circulation - exam 3 Flashcards
diffusion
one way to bring oxygen into cells
gases move from high to low concentrations
body plan needed for diffusion
requires large surface area
only works for thin animals
diffusion inversely related to distance
gastrovascular cavity
instead of a circulatory system
3 main features of circulatory systems
fluid
vessels
a pump
functions of circulatory systems
transport & exchange of respiratory gases
transport of nutrients, hormones, & immune cells
who has open circulatory systems
invertebrates
(not all)
fluid in open circulatory systems
hemolymph
mixes w/ interstitial fluid because the tubes are open ended
tradeoffs of open circulatory systems
does not require much energy
cannot move oxygen or nutrients quickly
who has closed circulatory systems
all vertebrates & some invertebrates
fluid in closed circ systems
blood in closed vessels
separate from interstitial fluid
tradeoffs of closed circ systems
uses a lot of energy
quickly delivers oxygen
arteries
carry blood away from heart
under high pressure from the heart
thick & elastic
surrounded by smooth muscle
arterioles
smaller than arteries
take the blood to capillaries
capillaries
microscopic vessels w/ thin porous walls
surround tissues & exchange surfaces
site of gas & nutrient exchange
blood slows down here
venules
why does blood slow down in the capillaries
big artery flows into MANY tiny capillaries
the total area of capillaries > area of artery
vein
carries blood back to the heart
under less pressure than arteries
thin & thin walled
valves
valves
help blood get back to the heart against gravity
close off section by section of veins so the blood can’t fall back down
what do the muscles in the walls of veins & venules do
help return blood to the heart
varicose veins
swollen veins
caused by damage to valves
atrium
chamber of the heart that receives blood
ventricle
chamber of the heart that pumps blood out
single circulation
blood travels through the body in a single loop
blood flows the heart ONCE