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
single circulation process
heart pumps once to take blood to respiratory surface & to body (where it slows down)
contraction of muscles speeds up circulation
what type of animals use single circulation
fish
double circulation
2 circuits of blood flow
blood flows through the heart TWICE
pulmocutaneous circuit
right side of the heart pumps oxygen poor blood into capillary beds & oxygen moves in
what types of animals use pulmocutaneous circuits
amphibians
systemic circuit
left side of heart pumps oxygen rich blood to the rest of the body
ventricle in double circulation for amphibians
mixing of oxygen rich & poor blood
why is ventricle in double circ in amphibians efficient
intermittent breathers
when underwater, incomplete division of ventricle allows frogs to shut off blood flow to lungs & shift it to the skin
pulmonary circuit
right side of heart pumps oxygen poor blood into capillary beds & oxygen moves in
no “cutaneous” –> don’t breathe through skin
what types of animals use pulmonary circuits
mammals
how many chambers in mammal hearts
4 chambers
ventricles divided
result of divided ventricles
no mixing of oxygen rich & poor blood
very efficient - supports endothermic way of life
4 major components of blood
plasma
red blood cells
platelets
white cells
plasma
liquid portion of blood
contains dissolved nutrients, hormones, gases
platelets
help form blood clots
white cells
immune defenses against invaders
red blood cells
transport oxygen to all tissues in the body
erythrocytes
what is the protein found in RBCs
hemoglobin
where are rbcs made
stem cells from bone marrow
how does the shape of RBCs support their function
flat w/ little divot on top
increased surface area for diffusion of oxygen
hemoglobin stored in divot
hemoglobin function
transports oxygen
what is hemoglobin made up of
4 protein strands with hemes
hemes
groups in the protein strands of hemoglobins
iron at the center
purpose of iron
bonds 1 oxygen molecule
makes blood red
how many molecules of oxygen can 1 hemoglobin molecule carry
4
what happens when oxygen binds to one subunit of hemoglobin
the shape changes to increase affinity for oxygen
what happens when oxygen is released from 1 subunit of hemoglobin
the shape changes to decrease affinity for oxygen
cooperativity
allows hemoglobin to pick up the largest load of oxygen in the lungs
& to dropoff the largest load in distant tissue
carbon monoxide & hemoglobin
carbon monoxide binds irreversibly to hemoglobin
it has a higher affinity than oxygen
what causes oxygen to dissociate from hemoglobin
drop in oxygen pressure
co2 production
Bohr shift
hemoglobin releases even more oxygen when you exercise
feedback loop that maintains RBCs
low oxygen detected by kidney
kidney secretes erythropoietin (EPO)
EPO causes bone marrow to make RBCs
high oxygen is detected by kidney
no more EPO released
respiratory adaptations in deep sea diving mammals
more blood - can store more oxygen
more myoglobin
blood not routed to muscles - muscles use myoglobin
myoglobin
oxygen storing protein IN MUSCLES rather than in blood
