carotid body

Question 1

carotid body is called the what, and why?

Answer 1

peripheral chemosensor: in the periphery, and senses oxygen levels in the blood

Question 2

how many carotid bodies? location? nerve?

Answer 2

2: in the bifurcation of the common carotid artery. carotid sinus nerve innervating it.

Question 3

carotid body: sensor of what 4 things

Answer 3

hypoxia (low arterial blood O2). hypercapnia (high arterial blood CO2). acidosis. hypoglycemia.

Question 4

structure of carotid body: cell types

Answer 4

clusters of type I glomus cells, which are enveloped by type II glial like sustentacular cells

Question 5

glomus cells: contain what? do what to what so info goes where?

Answer 5

secretory granules. glomus cells are what sense oxygen, and in response release transmitters and stimulate carotid sinus nerve and info is relayed to cardiorespiratory centre in brain stem.

Question 6

secretory in glomus cells: what 4 NTs

Answer 6

ATP, DA, ACh, histamine

Question 7

physiological role of CB; 2

Answer 7

adaptation to high altitudes. ensure sufficient oxygenated blood supply to tissues via fast respiratory and cardiocirculatory adjustments

Question 8

CB: acute hypoxia what adjustments do you get

Answer 8

increase rate of respiration and blood pressure (increase in sympathetic drive)

Question 9

pathophysiology of CB linked to what

Answer 9

sleep apnea related cardiovascular diseases

Question 10

sleep apnea; what? two types?

Answer 10

brief, repeitive cessations of breathing during sleep. obstructive and central.

Question 11

how does sleep apnea lead to cardiovascular problems

Answer 11

episodes of hypoxia during SA = low arterial O2 = stimulation/sensitization of CB = increase in sympathetic tone = congestive heart failure, hypertension, atherosclerosis

Question 12

animals: intermittent hypoxia cuases what?

Answer 12

increases hypoxic sensory response of the CB: you develop and increase in sympathetic tone and hypertension

Question 13

sleep apnea: denervation of carotid body?

Answer 13

blocks development of hypertension of animals subjected to intermittent hypoxia: so proves it’s the CB that causes hypertension

Question 14

sleep apnea and CHF and atherosclerosis

Answer 14

patients with CHF have enhanced activity of peripheral chemoreflex and sympathetic hyperactivities. intermittent hypoxia elevates plasma cholesterol, induces atherosclerosis

Question 15

what cell is the oxygen sensor

Answer 15

glomus cell

Question 16

hypoxia triggers what in what cell

Answer 16

glomus cell: hypoxia triggers firing of APs, and rise in intracellular calcium in single glomus cell

Question 17

experiment: single glomus cell recording membrane potential and calcium rise

Answer 17

normoxia: spontaneous APs and corresponding increases in [Ca]i. hypoxia: increase in Vm and AP firing, increase in calcium. back to normoxia: drop to basal state of Vm, normal Ca levels

Question 18

mechanism of oxygen sensing in CB

Answer 18

glomus cells sense hypoxia, respond with an increase in AP firing and calcium levels

Question 19

hypoxia triggers what two things from glomus cell

Answer 19

calcium intracellular rise, and transmitter release (measuring via carbon fiber amperometry)

Question 20

normoxia: what mmHg?

Answer 20

150 mmHg of oxygen is normal

Question 21

which NT actually stimulates the CSN

Answer 21

ATP (an experiment measured DA, but can be a measure of ATP release since in the same granules)