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Vascular system (p1) - Coggle Diagram
Vascular system (p1)
venous return mechanisms
skeletal muscle pump
muscles compress veins squeezing blood back to heart
smooth muscles in vessel walls
contracts smooth muscles to squeeze blood back
respiratory pump
pressure in thoracic cavity changes
pocket valves
prevents backflow of blood in veins
suction pump effect of heart
gravity
exercise and blood velocity
speed up in the arteries becasue heart contracts with more force
little change in cappilaries to allow for gas exchange
veins faster due to skeletal muscle pump
blood less viscous as it is warmer with exercise, moves quicker
blood pressure
blood * resistance to flow
sphygmomanometer
typical 120 / 80
effects on blood flow
force of contraction of the heart
the amount of cardiac output
the viscosity of the blood
increased venous return
resistance to blood flow
changes in the diameter of vessel lumen
atheromas
length of vessel - distance from heart
hypertension - 140 / 90
vessels
arteries
large leading away from heart
smaller lumen due to smooth muscle wall
branch into arterioles
highest blood pressure, velocitiy
smallest total cross sectional area
veins
return to heart
from venioles
slower blood velocity
medium total cross sectional area
lowest blood pressure
valves to prevent backflow
cappilaries
largest total cross sectional area
slowest velocity of blood to allow for diffusion and gas exchange
contain precapillary sphincters
one cell thick
oxy-haemoglobin dissociation curve
where there is a high PPO2 there is a high saturation of O2 with haemoglobin - lungs
where there is a lower PPO2 there is less saturation of O2 with haemoglobin - muscles
BOHR shift
cause
an increases in PPO2
increase in blood acidity
increased body temperature
graph moves right with exercise - more oxygen leaves haemoglobin and goes to the muscle for respiration
vascular shunt
chemoreceptors
baroceptors
proprioceptors
vasomotor control centre
reduced sympathetic stimulation
vasodilate arterioles - open precapillary sphincters
reduced blood flow to inactive organs and less active muscles
rapid sympathetic stimulation
vasoconstrict arterioles - close precapillary sphincters
increased blood flow to body, skin, coronary muscles