L22: Modulation Of Respiratory Control Flashcards

1
Q

What do chemoreceptors detect

A

Chemical changes in the blood

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2
Q

What do mechanoreceptors detect

A

Changes in the irritation and distension of airways and lungs

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3
Q

What are peripheral chemoreceptors

A

Sensory receptors that are located in the periphery i.e outside the central nervous system

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4
Q

Where are the 2 major location of peripheral chemoreceptors

A

Carotid bodies

Aortic bodies

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5
Q

What does peripheral chemoreceptors detect and respond to

A

Po2
Pco2
Ph

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6
Q

Where exactly is the aortic bodies located

A

Aortic arch

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7
Q

Where exactly is carotid bodies located

A

Bifurcation of the common carotid artery (in the neck) into external and internal common carotid artery

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8
Q

Does carotid bodies or aortic have the major functional role in ventilators control

A

Carotid bodies

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9
Q

What is the afferent nerve of the carotid body

A

Glossopharyngeal nerve

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10
Q

What is the afferent nerve of the aortic body

A

Vagus nerve

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11
Q

From the carotid and aortic body where does the vagus nerve and glossopharyngeal nerve (sensory nerves) go to

A

To NTS in the brainstem

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12
Q

What is a sinus

A

A swelling that contains baroreceptors

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13
Q

What are the sinuses located near the carotid and aortic bodies

A

Carotid sinus

Aortic sinus

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14
Q

Which cells in the bodies detect the changes in the blood gas

A

Globular/ type 1 cells

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15
Q

What happens to the firing of the carotid body as pao2 decreases

A

Increases

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16
Q

What happens to the firing of carotid bodies when there is a high paco2 and ph (metabolic acidosis)

A

Increases more

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17
Q

What is metabolic acidosis

A

An increases in H+ that is not related to co2 (breathing)

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18
Q

Overall what are the 3 stimulus that the carotid body increases it firing and responce

A

Hypoxia
Hypercapnia
Metabolic acidosis

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19
Q

What is the mechanism of sensing hypoxia in the carotid body

A

1) hypoxia acts on the mitochondria to inhibit oxidative phosphorylation (Electron transport chain)
2) atp production is reduced
3) amp increases
4) this is activated an enzyme called AMPK
5) AMPK inhibits pottassium channels on the type 1 cells in the carotid body
6) this leads to membrane depolarisation
7) voltage gated calcium channels open
8) neurotransmitters are released to synapses to induce an action potential to glossopharyngeal nerve

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20
Q

What can a carotid tumour be a result of

A

Hypoxia

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21
Q

Apart from peripheral chemoreceptors what are the other types of chemoreceptors found in the body

A

Central chemoreceptors

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22
Q

Where are the central chemoreceptors located

A

Brainstem of the CNS

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23
Q

Does central chemoreceptors respond to hypoxia

A

No

24
Q

What inhibits central chemoreceptors

A

Hypoxia

25
Q

What are central chemoreceptors sensitive to

A

Carbon dioxide

26
Q

What can pass through the blood brain barrier from the capillary bed to the chemoreceptors

A

Carbon dioxide (hypercapnia)

27
Q

What happens to carbon dioxide when it passes through the blood brain barrier into the medulla

A

Carbon dioxide reacts with water to give hydrogen and bicarbonate ions

28
Q

What stimulates the central chemoreceptors

A

Hydrogen ions from the reaction of carbon dioxide

29
Q

What happens when the central chemoreceptors are stimulated

A

It sends activity to the medullary respiratory neurones of DRG etc to adjust ventilation

30
Q

Does central chemoreceptors respond to metabolic acidosis

A

No it only responds to hypercapnia

31
Q

What is acclimatisation

A

Decrease in H+ in the CSF (brain) by active transport from blood to CSF and vice versa

32
Q

What membrane is between the CSF and arterial blood

A

Blood brain barrier

33
Q

What does blood brain barrier prevent

A

Ions and large polar molecules from entering the CSF

34
Q

What is respiratory acid change

A

Change in ph due to co2

35
Q

Does respiratory acid affect the ph of CSF

A

Yes because carbon dioxide can enter the CSF by passing the blood brain barrier

36
Q

Does metabolic acid affect the CSF ph

A

Not much because hydrogen ions cannot pass the blood brain barrier

37
Q

What happens when the CSF ph decreases

A

Alveolar ventilation increases

38
Q

Why does alveolar ventilation increase when ph of CSF decreases

A

To ventilate out carbon dioxide and return the ph back to normal

39
Q

When does alveolar ventilation increase the highest

A

Hypoxia and hypercapnia occurring at the same time

40
Q

Which gas controls pa02

A

Paco2

41
Q

What are the 3 types of mechanical receptors in the lung

A

Rapidly adapting irritant receptors
Slowly adapting stretch receptors
J-type or c-fibre receptors

42
Q

What do readily adapting irritant receptors respond to

A

Irritants that are inhaled

43
Q

What are the afferent nerve of the pulmonary mechanical receptros

A

Vagus nerve

44
Q

Where does the vagus nerve feed into in the brainstem after being activated

A

NTS then DRG

45
Q

What do mechanical receptors respond to

A

Foreign bodies
Chemical irritants
Immunologic challenges

46
Q

Where are rapidly adapting irritant receptors located

A

Between airway epithelial cells

47
Q

What does rapidly adapting irritant receptors cause

A

Cough
Bronchoconstriction
Hyperpnoea (increased ventilation)

All this occurs to stop irritant getting any further into the lung

48
Q

Where are slowly adapting stretch receptors located

A

Between smooth muscle cells

49
Q

What activates slowly adapting stretch receptors

A

Stretch

50
Q

What does the slowly adapting stretch receptors cause once activated

A

Inhibit inspiration and promote expiration
Bronchodilation
Tachycardia

51
Q

Where does the vagus afferent nerve feed into in the brainstem

A

NTS

52
Q

What is the stimulus of j-type/ c fibre receptors

A

Increase in interstitial fluid

53
Q

Where are j-type/c-fibre receptors located

A

Area between alveolus and pulmonary capillary

54
Q

What does j-type/c-fibre receptors cause once activated

A
Apnoea 
Bronchoconstriction 
Increased mucus secretion 
Hypotension 
Bradycardia
55
Q

What is apnoea

A

Shallow breathing