Blood Pressure Control and Hypertension Flashcards
What is the primary purpose of circulation?
To provide adequate blood flow to organs
What is MAP?
TPR x CO
Can capillaries change resistance?
No
How is TPR controlled?
Arterial constriction and relaxation
How is BP regulated in the short term?
neural - via the baroreflex
How is the baroreflex detected?
Stretch in arterial walls
Where are the baroreceptors located?
In the carotid sinus and the aortic arch
What causes more firing of the baroreceptors?
More stretch
How quick is the baroreceptor reflex response?
Very quick - occurs within one cardiac cycle
Where do the nerves from the baroreceptors go?
To the CV control centre in the medulla (in the brain stem)
What is the output of the CV control centre?
Sympathetic and parasympathetic nerves
What happens when the carotid artery is crushed?
The baroreceptor cells are stretched which makes the system think that pressure is too high, responds by dropping pressure and this results in a lack of perfusion to the brain and fainting
What is the action of the sympathetic nervous system on the CV system?
increase heart rate, decrease atrioventricular conduction time, increase contractility, increase TPR, increase venous tone
What is the action of the parasympathetic nervous system on the CV system?
reduce heart rate, increase atrioventricular conduction time
Can the baroreflex be reset?
Yes - responds to ambient change that persists for a few days
