Carotid sinus reflexes
From Carotid system
Afferent
Baroreceptor axons within CN9
Aortic arch baroreceptor axons within CN10
Stretch → ↑ baroreceptor firing → medulla oblongata
sensitive range = 80-150 mmHg
Efferent
glossopharyngeal + vagus nerves
Baroreceptor reflex
↓ CVP = less stretch = less firing
most sensitive 80-150mmHg + equilibrates to BP after a few hours
Important in short term BP maintenance
Action:
- ↑ arteriolar constriction (increase total peripheral resistance)
- ↑ venoconstriction (increase central venous pressure)
- ↑ Heart rate (increase cardiac output)
- ↑ Contractility (increase cardiac output)