Blood Pressure Regulation Flashcards
(29 cards)
SV, HR and TPR come together to determine_____
BP
What happens to the capillary flow if you increase the constriction of the arterioles?
The NFP will shift to favor absorption, and fluid will move into the blood. BP will rise
What is the main integrator of afferent input from baroreceptors?
Nucleus Tractus Solitarius (NTS)
Its in the brainstem
What are the 2 cardiovascular centers of the Nucles tractus solitarius (NTS)
- Vasomotor center
2. Cardiac center
What does the vasomotor center of the NTS do?
It regulates sympathetic adrenergic nerve activity to peripheral resistance vessels
What does the cardaic center of the NTS do?
It regulates efferent a gal and sympathetic nerve activity to the heart
Where are the arterial baroreceptors located and how do they measure pressure?
Located in aortic and carotid sinuses
Respond to stretch
What is the main function of the arterial baroreceptors?
Short term** regulation of blood pressure
How does the information from the baroreceptors get back to the NTS?
Via the vagus and glossopharyngral nerves
CN IX and X
How does efferent output from the NTS get to the targets?
Vagus nerve
Sympathetic nerves
How does the NTS respond to increased BP?
It increases parasympathetic stimulation to the SA node and decreases sympathetic stimulation to the heart and peripheral resistance
This causes decreased HR, TPR, SV, and CO, which leads to a decrease in MAP
What it the NTS response to a BP thats too low?
Decreased parasympathetic stim to the SA node.
Increased sympathetic stim to heart and peripheral resistance vessels
This causes increased HR, SV, CO, and TPR, which causes an increased MAP
Which is more potent: the response to baroreceptors or chemoreceptors?
Baroreceptors
Where are the peripheral chemoreceptors?
In the carotid bodies and aortic bodies
What activates the chemoreceptors?
Decreased O2 (hypoxia)
Increased CO2 (hypercapnia)
Decreased pH (acidosis)
What is the response of the vasomotor center of the NTS to chemoreceptor information saying the blood is too acidic, hypoxic, or hypercapnic?
Increased SNS stimulation of resistance vessels to increase TPR and BP
Is the response to baroreceptors and chemoreceptors short term or long term?
Very short term. Within seconds
What are the intermediate controllers that respond to changes in BP in minutes to hours?
Capillary fluid shift
Renin-angiotensin-aldosterone system
Vasopressin
Atrial natriuretic peptide
What effect will SNS have on the capiiaries in response to low BP
Vasoconstriction of the arterioles which causes decreased capillary hydrostatic pressure and increased fluid absorption form the interstitial fluid
What activates the renin-angiotensin system?
LOW blood volume**
How does the renin-angiotensin-aldosterone system work?
Renin is released due to low BP
Renin turns angiotensinogen into angiotensin I, which gets converted to angiotensin II in the lungs by ACE
Angiotensin II does two things: it is a potent vasoconstrictor, and it also causes the adrenal cortex to release aldosterone
Aldosterone causes increased Na absorption in the kidneys, which causes increased H2O absorption, and increases blood volume
What are the two ways the angiotensin II responds to low BP?
- It directly causes vasoconstriction
2. It causes a release of aldosterone (ADH)
What converts angiotensin I into angiotensin II?
ACE
angiotensin converting enzyme
What does antidiuretic hormone/Vasopressin do to protect blood pressure?
If there is decreased atrial stretch, it causes the posterior pituitary to release vasopressin/ADH which does two things: increases peripheral vasoconstriction and also increased H2O absorption in the kidney
