Short Term Control of Blood Pressure Flashcards
What is the driving force pushing blood through the circulation?
MAP
What happens if MAP is too low?
Fainting (syncope)
What happens if MAP is too high?
Hypertension
Where are the arterial baroreceptors found?
In the aortic arch and carotid sinus
What happens to the firing of the baroreceptors if blood pressure drops?
They fire slower
What type of receptors are the baroreceptors?
Stretch receptors
What is the relationship between the blood pressure and the stretching of the receptors?
The higher the blood pressure the greater the stretching of the baroreceptors
Where in the brain do the baroreceptors send information to?
The medullary cardiovascular centres
Which nerves take the sensory information to the medullary CV centres?
The vagus and glossopharyngeal nerve
Which nerves make up the motor innervation from the medullary CV centres?
Parasympathetic (vagus) and sympathetic nerves
Which gland does the sympathetic system also innervate with respect to blood pressure?
Adrenal medulla
What are the less important inputs to the CV centres
Cardiopulmonary baroreceptors, central chemoreceptors, chemoreceptors in muscle, joint receptors and higher centres
What effect does standing have on blood pressure?
The increased hydrostatic pressure causes pooling f blood in the veins of the feet and legs - this decreases VR, EDV, preload, SV, CO, MAP and therefore decreases the baroreceptor firing rate
How does the parasympathetic system counteract the effects of standing?
By decreasing vagal tone which causes an increase in heart rate and cardiac output
How does the sympathetic system counteract the effects of standing?
An increase in sympathetic tone increases HR, CO, contractility, venoconstriction and arteriolar constriction
