Neural Reflexes and Circulatory Control

Question 1

Baroreceptor reflex

Answer 1

Detect changes in pressure
Arterial baroreceptors (high pressure receptors in carotid sinus, aortic arch, and R subclavian artery)+ cardiopulmonary receptors (low pressure receptors)
SNS —> ↑ contractility, HR, venoconstriction = ↑ BP, TPA, and CO
PNS —> ↓ HR and slight contractility= ↓ BP

Question 2

Bainbridge reflex

Answer 2

↑ venous return to RA —> vagus nn —> cv center in medulla —> inhibition of PNS —> ↑ HR

Question 3

Chemoreceptor reflex

Answer 3

Within carotid and aortic body
Detect change in pH and blood O2
<50 mmHg /acidosis = ↑ respiratory centers and depths and rate of ventilation (PNS rxn) + ↓ HR/contractility

Question 4

Valsalva maneuver

Answer 4

Forced expiration against closed glottis
Produces ↑ intrathoracic pressure, central venous pressure, and ↓ venous return
Glottis open: Baroreceptors sense ↓ CO/BP —> ↑ HR/contractility (SNS)
Glottis closed: Baroreceptors sense ↑ CO/BP —> ↓ HR/contractility (PNS)