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arterial pulse as a pressure wave
what is systolic blood pressure determined by?
stroke volume
aortic elasticity
what happens to systolic BP is stroke volume is increased?
increases
what happens to systolic BP when elasticity is deceased?
increases.
what could inelastic aorta cause in the elderly?
systolic hypertension
mean blood pressure equation?
diastolic blood pressure +1/3 of pulse pressure (systolic-diastolic)
what happens to diastolic BP is peripheral resistance increases?
diastolic BP increases
what happens to diastolic BP when aortic elasticity is decreased?
decreases diastolic blood pressure
what happens to diastolic BP when heart rate is decreased?
DBP is decreased.
equation for mean arterial blood pressure?
cardiac output x total peripheral resistance (TPR)
systemic circulation stats
pulmonary circulation stats
why is control of arteriole blood pressure important?
provides a pressure head to drive blood flow permits activity, postural changes - protects against the effects of gravity.
how is control of arteriole blood pressure achieved?
pressure sensor (in circulation) - afferent input.
integration centres (in CNS) - efferent output.
effector mechanisms (via autonomic nervous system)
where are arteriole (high pressure) baroreceptors located?
walls of carotid sinus and aortic arch.
what are the key nerves in increasing and decreasing BP?
carotid sinus and the aortic nerves
what nerve system decreases heart rate?
parasympathetic nerve system
what nerve system increases heart rate?
sympathetic
what do aplha 1 adrenocpeptor in the blood vessels do?
cause vasoconstriction in blood vessels when activated
where are low pressure baroreceptors found?
pulmonary vasculature, atrial-vena caval junctions, ventricular walls.
what does an increase in transmural pressure do?
increase in afferent nerve discharge (vagus)
integrations centres diagram
what is a pressor area?
a tonically active area, baroreceptors tonically inhibit it
what is a depressor area?
not tonically active but is activated by an increase in baroreceptors afferent nerve discharge.
what happens when arterial blood pressure decreases diagram
what happens when arterial blood pressure increases diagram
why do people feel faint when going from sitting to standing?
not enough blood going to the brain for a short period of time.
what happens when blood pools in legs and abdomen?
decreased venous return
decreased CO and MAP
what happens when MAP falls?
unload cardiopulmonary receptors.
unload arterial baroreceptors.
leads to a decrease in afferent discharge.
what does a decrease in afferent discharge lead to?
decreased vagal efferent.
increased sympathetic efferent.
increased HR.
increases Stroke volume.
increased vasocontraction.
restored BP to normal.
how does DSP change when lying down and standing up?
lying down - diastolic is lower than normal
standing up - diastolic is higher than normal
why are sitting and standing BP different but MAP the same?
lower than normal CO (higher HR but lower StV)
higher than normal TPR.
normal MAP can be achieved with lower systolic BP and high diastolic BP.
Note 
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