BP Regulation Flashcards
The nervous system can’t really adjust blood flow to tissue, but it can do redistribute it by doing what?
Increasing HR
Which vessels are not innervated?
Capillaries and precapillary sphincters
In sympathetic nerves, there are more (vasoconstrictor or vasodilator) fibers
Vasoconstrictor = decreases volume and increases pumping (CO)
Which center transmit parasympathetic impulses through the vagal nerve to the heart?
Vasomotor center
Describe sympathetic vasoconstrictor tone
impulses transmitted continuosly to maintain partial contraction in bv (vasomotor tone)
List the 3 areas of the vasomotor center
- Vasoconstrictor
- Vasodilator
- Sensory
Which portion of the vasomotor center transmits excitatory impulses to increase HR?
Lateral portion
Why does Arterial pressure drop with spinal anesthesia?
Because of loss of vasoconstrictor tone
What type of feedback system does the Baroreceptor reflex work as?
Negative
Carotid receptors go via which CN to the VMC?
Glossopharyngeal (9)
Aortic arch receptors go via which CN to the VMC?
Vagus (10)
At what pressure are baroreceptors most sensitive?
100mmHg
If baroreceptors are activated, what happens to arterial pressure?
Decreases
How much time do baroreceptors take to reset, thus making them unuseful for long-term control of arterial pressure?
1-2 days
What are AP chemoreceptors sensitive to?
O2, CO2 and H ions
At what pressure do chemoreceptors get activated?
80 mm Hg or less
The last ditch stand is the name given to what response?
CNS ischemia response
When BP falls below 60 mmHg, what is activated?
CNS ischemia response
When the AP is increased above CSF Pressure, what reaction occurs to relieve the ischemia?
Cushing reaction
When the blood volume and AP rise with an excess in extracellular fluid which body system can help bring back the pressure?
Renal system
What is the term for an increase in sodium output?
Pressure Natriuresis
List the 2 long-term determinants of AP level
- level of salt + water intake
- Degrees of pressure shift of the renal function curve
T/F CO increase means AP is directly and indirectly increased
True
What ion can increase AP more than water?
Salt
What is the limit for MAP to be considered hypertension?
110 mmHg (90/135)
What are the 2 long term ways AP is regulated?
Renin-angiotensin system
aldosterone
What happens to renal blood flow in the late stages of hypertension?
Decreased to half normal
What is the primary precursor to Aldosterone?
Angiotensinogen
Which secondary precursor of aldosterone can increase AP directly?
Angiotensin II
Excess aldosterone levels (aldosteronism) can lead to?
Hypertension
Chronic control of BP is regulated by the ______________
Kidneys
Acute control of Circulation is regulated by the _____________________
Nervous system
