Initiation of Breathing Flashcards

1
Q

Neurogenic initiation

What 2 things did Thomas Lumsden (1923) discover?

think:

  • respiratory centres
  • medulla and pons
A
  • Discovered that 3 CNS respiratory centres were involved
  • The medulla is of primary importance in breathing and Pons smooths out breathing
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2
Q

The respiratory centre

what type of groups send impulses to respiratory muscles

A
  • bi-lateral groups
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3
Q

the respiratory centre

what do the Dorsal and ventral respiratory groups do?

A

medullary rhythmicity (initiation of breathing)

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4
Q

the respiratory centre

what type of nuclei does the dorsal respiratory group have and where is it found anatomically in the medulla

A
  • has inspiratory nuclei
  • found in the dorsal (posterior) section of medulla
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5
Q

the respiratory centre

what type of nuclei do the ventral respiratory groups have and where are they found anatomically

A

has inspiratory and expiratory groups

  • VRGs are found bilaterally and ventrally (anterior) in the medulla
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6
Q

where are the pneumotaxic and apneustic centres found and state which one is inhibitory and which one is excitatory?

A

Pneumotaxic centre:
- upper pons
- inhibitory (limits depth of inspirtation which increases rate of breathing)

apneustic centre:
- lower pons
- excitatory

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7
Q

THe repiratory centre

what is the main function of:

  • Pneumotaxic centre
  • Apneustic center
A

Pneumotaxic centre:
- control rate and depth of breathing (limits inspiration)

Apneustic centre:
- modulates (smooths) breathing cycle to stop things like abrupt halts in inspiration and integrates inspiratory cutoff

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8
Q

the respiratory centre

where does the pneumotaxic centre feed into

A

feeds into the DRG

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9
Q

DRG

what nucleus is the dorsal respiratory group found in

A

the Nucleus tractus solitarius

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10
Q

DRG

where is the Dorsal respiratory group located anatomically

A

dorsally (posteriorly) in the medulla

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11
Q

Dorsal respiatroy group (DRG) - medulla

what do the nuclei in the nucleus tractus solitarius drive

A

drives breathing movements and timing

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12
Q

DRG

what 4 structures does nucleus tractus solitaris get sensory information from?

Think: 2 types of receptors
2 types of nerve

A
  • Chemoreceptors
  • proprioceptors
  • vagus nerve
  • glossopharyngeal nerve
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13
Q

DRG

where does the nucleus tractus solitarius output to?

A

outputs to inspiratory muscles

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14
Q

DRG

outline the nature of the action potentials from the nucleus tractus solitarius to the inspiratory muscles

A

repetitive “ramped” bursts of inspiratory neuronal action potentials for 2 secs, allowing inspiration, and then 3 seconds off, allowing for expiration

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15
Q

Ventral Respiratory Group (VRG)

where is the VRGs compared to:
- the medulla
- DRG

A

either side of medulla and anterior and lateral to the DRG

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16
Q

VRG

which 2 nuclei is the VRG located in

A

located in:
- nucleus para-ambiguus
- nucleus retroambiguus

17
Q

where does the nucleus para-ambiguus supply?

A
  • Laryngeal muscles
  • pharyngeal muscles
18
Q

where does the nucleus retroambiguus supply

A

diaphragm and external intercostal muscles

19
Q

VRG

what does the VRG contain nuclei for?

A

both inspiratory and expiratory nuclei

20
Q

VRG

what type of breathing is VRG involved in?

A
  • active inspiration
  • active expiration (ie: voluntary forced exhalation)
21
Q

VRG

when in the VRG inactive

A

inactive in normal quiet breathing

VRG is inactive in normal breathing and only activates in ACTIVE breathing

22
Q

VRG

what places do the nucleus retroambiguus and the nucleus para-ambiguus in the VRG feed into

A

Nucleus retroambiguus:
- diaphragm and external intercostal muscles

Nucleus Para-ambiguus:
- Laryngeal and pharyngeal muscles

23
Q

Central pattern generation

what are the 3 phases of central pattern generation for breathing

A
  • inspiratory phase
  • post inspiratory/expiratory phase 1
  • expiratory phase II
24
Q

central pattern generation

what neurotransmitters are associated in central pattern generation in breathing

A
  • NDMA
  • GABA
25
Q

central pattern generation

where are neurones with different firing patterns concentrated near in breathing?

A

concentrated near pre-Botzinger complex

26
Q

efferent pathway from the respiratory centres

what spinal tract come from the respiratory centres in breathing

A

Bulbospinal Tract

27
Q

efferent pathways from respiratory centres

where does the phrenic nerve originate from?

A

rootlets formed from cervical spinal nerves C3,C4 and C5

C3, C4, C5 keep the diaphragm alive

28
Q

efferent pathway

where do intercostal nerves exit and where do they provide input to?

A
  • exit thoracic and lumbar spine
  • provide input to the intercostal and abdominal muscles
29
Q

efferent pathways

what does the phrenic nerve do and where does it originate

A
  • gives motor control to the diaphragm
  • formed by rootlets coming from cervical spine C3,C4,C5

C3, C4, C5 keep the diaphragm alive

30
Q

Pneumotaxic centre (upper pons)

outline the 3 steps of how pneumotaxic centre stops the lungs becoming too full

think:
- inhibitory impulses
- limiting activity of 2 places
- what this leads to

A
  1. Pneumotaxic centre sends continual inhibitory impulses to inspiratory centre in DRG of medulla oblongata
  2. this limits activity of phrenic nerve and inhibits apneustic centre
  3. this decreases the tidal volume which prevents the lungs becoming too full
31
Q

Pneumotaxic centre

what happens in you stimulate the pneumotaxic centre more vs if you stimulated less

A

stimulated more: breathe fast and shallow

Stimulated less: inspiratory depth increases and slower breaths

32
Q

apneustic centre

what does overstimulation of the apneustic centre do and how?

A

causes apneusis (gasping) by exciting inspiratory neurones, prolonging inspiration

33
Q

what happens if there is damage to the apneustic centre?

A

respiratory cycle is abrupt (no smoothness)

34
Q

what 2 things inhibits the apneustic centre?

A
  • Stretch receptors at (max inspiration)
  • Pneumotaxic centre
35
Q

PNeumotaxic centre

what happens if you have upper pons damage

A

Deep long breaths as pneumotaxic centre is most likely damaged.

36
Q

What 2 nerves is the nucleus tractus solitairus a sensory terminal for and what do these nerves do?

A

2 nerves:
- vagus
- glossopharyngeal

These nerves transmit sensory signals from different receptors to therespiratory centre

37
Q

outline where the bulbospinal inspiratory neurones start, descend to and where they end

A

descend: from respiratory centre to the anterolateral column of the spinal cord

terminates: in anterior horn of cervical and thoracic vertebral segments.