Control of Ventilation: Peripheral Chemoreceptors Flashcards Preview

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Flashcards in Control of Ventilation: Peripheral Chemoreceptors Deck (26)
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1

The peripheral chemoreceptors are located in the

Carotid body

(at the bifurcation of the carotid artery)

2

The peripheral chemoreceptors are located in the carotid body at the bifurcation of the carotid artery. Which structure also contains chemoreceptors?

Transverse aortic arch

3

The transverse aortic arch also contains chemoreceptors, but its primary job is to

Monitor arterial blood pressure

4

The chief responsibility of the carotid body is to monitor

Hypoxemia

(Pa02 < 60 mmHg)

5

Hypoxemia is described as PaO2 of which value?

 

Pa02 < 60 mmHg

6

True or False

Peripheral Chemoreceptors in the carotid body do not respond to SaO2 or CaO2

True

Peripheral Chemoreceptors in the carotid body do not respond to SaO2 or CaO2

7

Secondary responsibilities of Peripheral Chemoreceptors in the carotid body include monitoring of

PaC02

H+

Perfusion pressure

8

How does the body respond to Hypoxemia? Describe The Hypoxic Ventilatory Response

  • Pa02 < 60 mmHg closes the oxygen-sensitive K+ channels in Type I Glomus cells.
  • This raises resting membrane potential, opens Ca+2 channels, and increases neurotransmitter release (Ach and ATP).
  • An action potential is propagated along Hering's nerve then along the glossopharyngeal nerve (CN IX).
  • The afferent pathway terminates in the inspiratory center in the medulla.
  • Minute ventilation increases to restore Pa02.

 

9

Pa02 < 60 mmHg

A. opens the oxygen-sensitive K+ channels in Type I Glomus cells

B. closes the oxygen-sensitive K+ channels in Type I Glomus cells

closes the oxygen-sensitive K+ channels in Type I Glomus cells

10

Pa02 < 60 mmHg closes the oxygen-sensitive K+ channels in Type I Glomus cells. What effect does this have on resting membrane potential, Ca+2 channels, and neurotransmitter release (Ach and ATP)?

 

 

Raises resting membrane potential

Opens Ca+2 channels

Increases neurotransmitter release (Ach and ATP

11

An action potential is propagated along which nerves?

Hering's nerve

Glossopharyngeal nerve (CN IX).

12

The afferent pathway terminates in the

inspiratory center in the medulla

13

 which increases to restore Pa02?

Minute ventilation

14

Which conditions impair the Hypoxic Ventilatory Response?

 

Carotid endarterectomy

Sub-anesthetic doses of inhalation and intravenous anesthetics (0.1 MAC)

15

Why don't we do bilateral CEA simultaneously or very close to each other?

 

Carotid endarterectomy severs the afferent limb of the hypoxic ventilatory response

It takes time for the body to recalibrate

16

How does Sub -anesthetic doses of inhalation and intravenous anesthetics (0.1 MAC) impair the Hypoxic Ventilatory Response?

Depress the hypoxic ventilatory drive

17

Sub -anesthetic doses of inhalation and intravenous anesthetics (0.1 MAC) depress the hypoxic ventilatory drive, how does this affect postoperative hypoxia?

Not always countered by a reflexive increase in minute ventilation.

18

What effect do volatile anesthetics have on diaphragmatic, intercostal, and upper airway muscle function?

impair diaphragmatic, intercostal, and upper airway muscle function.

19

Which conditions  Do NOT Impair the Hypoxic Ventilatory Response

Anemia

Carbon monoxide poisoning

20

Even though Ca02 is reduced with anemia as well as carbon monoxide poisoning, why is it that these conditions do not stimulate the hypoxic ventilatory response?

Pa02 is usually normal

21

While the central chemoreceptor in the medulla primarily responds to PaC02, the peripheral chemoreceptors in the carotid bodies primarily respond to

A. Pa02

B. Sa02

Pa02

22

Which cells mediate the hypoxic ventilatory drive?

 

Type I Glomus cells

23

Which cells are the sensors that transduce PaO2 into an action potential?

Type I Glomus cells

24

Type I Glomus cells are the sensors that transduce Pa02 into an action potential. This action potential is propagated along the afferent limb, which consists of which two nerves?

Hering's nerve

Glossopharyngeal nerve (CN IX).

25

Unilateral Carotid endarterectomy impairs the function of the peripheral chemoreceptors on

A. both sides

B. the same side

Same side

26

References:

 

Flood. Stoelting's Pharmacology & Physiology in Anesthetic Practice. 5th ed. 2015. p. 579-580.

Hemmings. Pharmacology and Physiology for Anesthesia: Foundations and Clinical Application. 2013. p. 454-455