Control of lung function (33) Flashcards

1
Q

What are the 3 major respiratory groups of neurons in the respiratory centre?

A
  • in medulla: dorsal respiratory group and ventral respiratory group
  • in pons, pontine respiratory group has two area: pneumotaxic centre and apneustic centre
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2
Q

What is DIVE a mnemonic to remember?

A

Dorsal Inspire Ventral Expire

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3
Q

What is the role of the dorsal respiratory group?

A
  • initiates inspiration
  • sets and maintains rate of respiration
  • integrating centre that gives output to VRG
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4
Q

What is the role of the ventral respiratory group?

A
  • expiratory centre
  • inactive during quiet, restful breathing
  • sends inhibitory impulses to apneustic centre
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5
Q

What is the role of the apneustic centre?

A
  • stimulates activity in DRG
  • inhibited by pulmonary stretch receptors
  • inhibits pneumotaxic centre
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6
Q

What is the role of the pneumotaxic centre?

A
  • controls both the rate and the pattern of breathing
  • antagonist to apneustic centre, which produces abnormal breathing during inhalation
  • limits inspiration, providing ‘inspiratory off-switch’
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7
Q

Which nerve drives breathing?

A

phrenic nerve- innervates diaphragm

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8
Q

What cells help keep tight junctions in place in the blood-brain barrier?

A

glial cells

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9
Q

How do the central chemoreceptors in the medulla sense changes in H+?

A
  • H+ cannot dissolve across the endothelial cells, as they are charged
  • CO2 can move through (v. lipid soluble)–> combines w/ water to form H+ and bicarbonate in CSF
  • chemoreceptors detect H+ in ventral surface of medulla

N.B. CO2 reflects metabolism

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10
Q

What are irritant receptors?

A
  • in airways
  • afferent receptors within epithelium that detect irritants e.g. particulates, water
  • leads to cough–> glottal closure and contraction of respiratory muscles then glottal opening and rapid expulsion of air
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11
Q

What are stretch receptors?

A
  • in airway smooth muscle
  • detect excessive inflation (Hering–Breuer inspiratory-inhibitory reflex to prevent hyperinflation of lungs)
  • inspiration inhibited and expiration stimulated
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12
Q

What are J receptors/pulmonary C-fiber receptors?

A
  • next to capillaries of alveoli
  • detect accumulation of fluid or identify pulmonary capillary engorgement
  • -> increases breathing frequency bc these ^ cause a decrease in oxygenation
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13
Q

What is alkalaemia?

A

refers to higher than normal pH of blood

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14
Q

What is acidaemia?

A

refers to lower than normal pH of blood

snapshot in time

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15
Q

What is alkalosis?

A

circumstances that will decrease [H+] and increase pH

and create alkalaemia

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16
Q

What is acidosis?

A

circumstances that will increase [H+] and decrease pH

17
Q

What can stimulate a rapid compensatory response to change CO2 elimination and so alter pH?

A

changes in ventilation

–> a low level of CO2 in the blood results from rapid or deep breathing

18
Q

What can stimulate a slow compensatory response to increase/decrease pH?

A

changes in HCO3- and H+ retention/secretion in the kidneys

19
Q

Where are peripheral chemoreceptors located and which cranial nerves innervate them?

A
  • aortic arch and carotid bodies

- CN IX and X

20
Q

What is the stimulus for peripheral chemoreceptors?

A

responds directly to changes in PaO2 (mainly), PaCO2

21
Q

How do strong emotions/pain lead to changes in ventilation?

A

act via hypothalamus, limbic system–> signal respiratory centres–> modify respiratory rate, depth

22
Q

How does exercise lead to a change in breathing?

A
  • efferents from primary motor cortes simultaneously activates skeletal muscle and respiratory centres in medulla
  • proprioceptors in moving muscles, tendons+ joints stimulate respiratory centres
23
Q

How does skin input affect breathing in the cold shock response?

A
  • thermoreceptors detect cold water

- leads to hyperventilation/inspiratory gasp