Carotid Bodies - Anatomy

Question 1

What is 1-heme-oxygenase-2?

Answer 1

Enzyme that converts heme to biliverdin
producing CO

Question 2

What does carbon monoxide cause?

Answer 2

K+ channels open (controversial)

Question 3

What is the 2nd theory?

Answer 3

L-cysteine broken down into H2S by O2
O2 further breaks down H2S into SO23-

Question 4

What is the third theory?

Answer 4

Increased AMPK activity

Question 5

What does AMPK sense?

Answer 5

ATP levels

Question 6

What happens with AMPK in hypoxia?

Answer 6

In hypoxia -> more AMP than ATP -> AMPK is phosphorylated (active) -> active form inhibits K+ channel

Question 7

What is the fourth theory?

Answer 7

ROS-Theory

Question 8

What is the ROS Theory?

Answer 8

In hypoxia ROS increases -> signals AMPK -> AMPK is phosphorylated -> K+ channels close

Question 9

What happens to type 2 glomus cells in extensive hypoxia?

Answer 9

Differentiated into type 1 cells

Question 10

What are 6 diseases associated with carotid bodies?

Answer 10

Glomectomy leads to loss of hypoxic responsiveness
CB dysfunction in SIDS
Congenital central hypoventilation syndrome
COPD
Chronic hypoxia
CB tumours

Question 11

Define hypoxia.

Answer 11

Occurs when oxygen demand exceeds supply & is detected by the carotid bodies