Continuous and intermittent Flow Flashcards
What is the role of elastic arteries
convert the pumping of the heart into continuous blood flow
- dampening the pressure changes
- distribution of blood
What is the composition of the elastic arteries
endothelium, elastin, smooth muscle, collagen
What is the role of elastin
allows the walls of the arteries to expand as well as storing potential energy for expansion during systole
- allowing all the blood flow to all the tissues that needs the blood and other stuff
What is the role of collagen
during diastole, the potential energy would be released to keep the blood flow going on
how does the arteries convert the pumping into the continuous flow
- mid systole - energy used to stretch the walls
- end of systole, energy stored in elastin
- mid diastole - energy released during elastin recoil
- end diastole - elastin return to OG shape
What is ABP determined by
in the elastic arteries and is the driving force for the blood flow
-SP AND DP too
how to calculate pulse pressure
systolic P - diastolic P
how to calculate mean arterial blood pressure
DP +((SP -DP)/3) so aorund 93mmHg
What does MAP determine
diffusion of substances across the tissues
factors affecting SP, DP, MAP
elastin content, stroke vol and peripheral R
factors affecting SP
- SV ejected into the aorta
- aorta distensibility ( how elastic )
- ejection Velocity
- DP of prevoius beat
- contractility
factors affecting DP
- arteriolar R - vasoconstriction or dilation
- arterial distensibility
- HR
how does ageing have an effect on arterial distensibility
- as the age increases, the it becomes less elastic
why does SP increases if the elasticity is reduced
the arteries wont be elastic so it wont recoil therefore, the pressure need to be increases to accommodate the flow
why does DP decrease if the elasticity is reduced
less energy is stored in the elastin so when less energy is released too
what happens to the SP, DP and MAP during MAP
-SP- increased due to increased SV
-TPR - decreased due to muscles dilation so
DP is decreased
-MAP same for sufficient diffusion
how is the alveolar gas composition constane
- the ventilation and the metabolism is matched
- so O2 and CO2 entering and leaving is the same in RS
- this is important so the arterial blood environment is constant too
what is the function of capillaires
exchange of substance
composition of capillaries
purely endothelium so one cell thick
types of capillaries
continous and fenesrated
what happens to the CSA and velocity in the capillaries
CSA increases as it branches into smaller ones so the velocity decreases
- flow is slow so the substances can be exchanged
forces involved fluid filtration in the capillaries
-capillary hydrostatic P
-interstitial oncotic P
interstitial hydrostaic P
plasma oncotic p
work out net filtration?
Kf x(forces favouring filtration ) - (forces favouring reabsorption)
how is the fluid filterated and reabsorbed in peripheral capillaries
- the hydrostatic pressure is higher than oncotic P at the arterial end so the fluid leaves
- the hydrostatic P is lower than the oncotic P so the fluid is reabsorbed
- filtration = reabsorption so no net filtration
what is the net movement of fluid during vasoconstriction
-net reabsorption because the TPR is increased, leading to lower hydrostatic P
what is the net movement of fluid during vasodilation
Net filtration becuase the TPR is lower and the hydrostatic pressure is higher due to less energy being lost
