Stimulus-Response of Carotid Body (PK9)

Question 1

What do carotid bodies account for all ventilatory response to change to?

Answer 1

PO2

Question 2

What percentage of resting ventilation is accounted for by carotid bodies?

Answer 2

15%

Question 3

What percentage of response to CO2 is accounted for by carotid bodies?

Answer 3

20%

Question 4

Mechanism of carotid body sensing hypoxia

Answer 4

• Hypoxia inhibits oxidative phosphorylation
• Increases cytosolic AMP/ATP ratio
• Activates AMPK (via LKB1)
• Inhibits BK/TASK K+ channels –> membrane depolarised
• Opens voltage-gated calcium channels
• Neurosecretion induces action potential across synapses to afferent neurones