BP control Flashcards
what is the equation relating MAP, CO and TPR
MAP = CO x TPR (total peripheral resistance)
CO= HR x SV
what affect do the following have on stroke volume
- SNS activity, Frank Starling mechanisms, and right atrial pressure
All increase SV
what are the three short term, rapid (sec-min) regulation mechanisms of blood pressure
- baroreceptors
- low-pressure receptors
- brainbridge reflex
what are the two intermediate, (minutes to hours) regulation mechanisms to control BP
- capillary fluid shift
- stress relaxation
what are the two long, slow (hours+) regulation mechanisms to control BP
- renin angiotensin system
- antidiuretic hormone
baroreceptors are strategically located to monitor MAP. What do they respond to?
vascular stretch induced by changes in blood pressure
carotid sinus baroreceptor is innervated by what nerve
glossopharyngeal nerve
aortic branch baroreceptor is innervated by what nerves
right and left vagus nerve
what causes an increase firing rate in baroreceptors
increases in arterial Pressure
What are the BP thresholds for evoking impulses (min and max)
- impulses occur at 50-60 mmHg
- maximum rates at 200mmHg
an increasing rate of pressure change (dP/dT) has what effect on baroreceptor firing rate
increases firing rate
*frequency during the rising systolic pressure is greater than that in diastole
maximal sensitivity is normally at what MAP?
100 mmHg
with chronic HTN, what happens to the set point , point of maximal sensitivity?
set point is reset at a higher pressure, the curve shifts to the right
with chronic HTN, what happens to the sensitivity of the reflex to operate
there is a loss of sensitivity of the reflex to operate
*the slope is decreased
in the baroreceptor reflex arc, what structure recieves sensory neurons from the baroreceptors in carotid sinus and arch of aorta?
medulla oblongata