Peripheral Vascular Controls Flashcards
Differentiate the sympathetic nerve receptors and functions for vasculature.
Alpha-adrenergic: Vasoconstrictors
B2-adrenergic: Vasodilators on coronary vessels
How do the coronary arteries adjust response to Ach?
If healthy, causes vasodilation
If damaged endothelium, caused Vasoconstriction
How does ADH affect the CV System?
- response to increase osmolality or decrease in BP
- Increase renal fluid retention
- can cause Vasoconstriction in hemorrhage.
- Activates IP3 pathway
Describe the hormonal control of CV system by angiotensin II.
- Released because of Renal artery pressure drop or sympathetic NS signals release
- Activates IP3 pathway
Describe the hormonal control of CV system via ANP.
- Releases secondary to stretch from hypertension
- Receptor is guanylyl cyclones which activates pkG and releases smooth muscles cells
Describe the Baroreceptor reflex.
- 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.
Compare Carotid vs aortic Baroresponse.
Loss of carotid baroreceptor response greatly decreased mean aortic pressure (34%) as compared to aortic response (12%).
What is gain?
Ratio of the secondary change evoked by a given mechanism to initiating change itself
Greater than 1: Vicious cycle
Less than 1: Not vicious
How does Cardiac failure affect blood chemistry and pH? How does this affect the heart?
- Decreased O2 —> Lactid Acid build up
- Inadequate excretion of H+ by kidneys
- Generalized metabolic acidosis —> Reduced tissue perfusion and further aggregates acidosis