Short Term Control of Blood Pressure Flashcards
What is the equation used to calculate MAP?
MAP = CO x TPR
What is mean arterial pressure?
The driving force pushing blood through the circulation
What would low MAP cause?
Fainting
What would high MAP cause?
Hypertension
What does the arterial baroreflex minimise?
Fluctuations in the MAP
What kind of nerve endings are baroreceptors?
Afferent
What effect will decreased blood pressure have on baroreflex activation?
Baroreflex activation will decrease
Where are baroreceptors located?
Aortic arch and carotid sinus
Through what nerves do the baroreceptors send signals to the medullary cardiovascular centres?
Vagus and Glossopharyngeal nerves
Through what nervous system does the response to the signals sent by the baroreceptors travel from the medullary cardiovascular centres to the heart?
Autonomic nervous system
Will venoconstriction and arteriolar constriction be caused by high or low pressure?
Low pressure
Give 3 other inputs to the medullary cardiovascular centres
- cardiopulmonary baroreceptors
- central chemoreceptors
- chemoreceptors in muscle
- joint receptors
- higher centres
Can arterial baroreceptors regulate blood pressure in the long term?
No
What does the long term control of blood pressure depend on?
Blood volume
What effect does standing have on hydrostatic pressure?
Standing increases hydrostatic pressure
What does increased hydrostatic pressure cause in the feet/legs?
Pooling of blood in veins/venules of the feet/legs
What effect does standing have on baroreceptor firing rate?
Decreases baroreceptor firing rate
What effect does the reflex response have on vagal tone?
Decreases vagal tone
In the reflex response, what increases with decreasing vagal tone?
Heart rate
Cardiac output
Give 3 factors that increase with increased sympathetic tone
- contractility
- venoconstriction
- arteriolar constriction
What effect is there on thoracic pressure in the Valsalva manoeuvre?
Thoracic pressure increases
What receptors detect the decrease in MAP in the Valsalva manoeuvre?
Baroreceptors
In the Valsalva manoeuvre, the decrease in thoracic pressure is transmitted through to the
aorta
In the Valsalva manoeuvre, decreased MAP is detected by baroreceptors which initiate reflex causing increased
cardiac output and TPR
