Peripheral Vascular Controls

Question 1

Differentiate the sympathetic nerve receptors and functions for vasculature.

Answer 1

Alpha-adrenergic: Vasoconstrictors

B2-adrenergic: Vasodilators on coronary vessels

Question 2

How do the coronary arteries adjust response to Ach?

Answer 2

If healthy, causes vasodilation

If damaged endothelium, caused Vasoconstriction

Question 3

How does ADH affect the CV System?

Answer 3

• response to increase osmolality or decrease in BP
• Increase renal fluid retention
• can cause Vasoconstriction in hemorrhage.
• Activates IP3 pathway

Question 4

Describe the hormonal control of CV system by angiotensin II.

Answer 4

• Released because of Renal artery pressure drop or sympathetic NS signals release
• Activates IP3 pathway

Question 5

Describe the hormonal control of CV system via ANP.

Answer 5

• Releases secondary to stretch from hypertension

- Receptor is guanylyl cyclones which activates pkG and releases smooth muscles cells

Question 6

Describe the Baroreceptor reflex.

Answer 6

• reductions in Pa and
  pulse pressure during hemorrhage decrease stimulation of the baroreceptors in the carotid sinuses and aortic arch
• responses include reduction of vagal tone
  and enhancement of sympathetic tone, increased
  heart rate, and enhanced myocardial contractility.

Question 7

Compare Carotid vs aortic Baroresponse.

Answer 7

Loss of carotid baroreceptor response greatly decreased mean aortic pressure (34%) as compared to aortic response (12%).

Question 8

What is gain?

Answer 8

Ratio of the secondary change evoked by a given mechanism to initiating change itself

Greater than 1: Vicious cycle
Less than 1: Not vicious

Question 9

How does Cardiac failure affect blood chemistry and pH? How does this affect the heart?

Answer 9

• Decreased O2 —> Lactid Acid build up
• Inadequate excretion of H+ by kidneys
• Generalized metabolic acidosis —> Reduced tissue perfusion and further aggregates acidosis