3. Control of ventilation COPY Flashcards

1
Q

How are skeletal muscles stimulated during inspiration?

A

Phrenic nerve to diaphragm

Intercostal nerves to external intercostal muscles

Entirely dependant on signalling from the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What part of the brain is responsible for ventilatory control?

A

Il defined centres located in the pons and the medulla (respiratory centres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the activity of respiratory centres?

A

Fire repetitive short bursts of action potentials in DRG which travel to the inspiratory muscles

This sets an autonomic rhythm of breathing

They adjust their rhythm according to the stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does DRG stand for?

A

Dorsal respiratory group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does PRG stand for?

A

Pontine respiratory group - pneumotaxic area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does VRG stand for?

A

Ventral respiratory group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does NTS stand for?

A

Nucleus tractis soolitaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which respiratory centre is located in the pons?

A

PRG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What modulates rhythm of respiratory centres?

A
  • Emotion (limbic system of brain)
  • Voluntary over-ride (higher centres in the brain)
  • Mechano-sensory input from the thorax (stretch reflex)
  • Chemical composition of the blood (PCO2, PO2 and pH) – detected by chemoreceptors.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the VRG supply?

A

Tongue, pharnyx, larynx, expiratory muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the DRG supply?

A

Inspiratory muscles via phrenic nerve and intercostal nerve.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the most significant input?

A

Chemoreceptor input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are your central chemoreceptors?

A

Medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What chemical change does the medulla detect from the CSF?

A

Responds directly to H+, which directly reflects PCO2

Primary ventilatory drive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are your peripheral chemoreceptors?

A

Carotid and aortic bodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What chemical change do the peripheral chemoreceptors detect?

A

Primarily to plasma [H+] and PO2 (not oxygen content) (less so to PCO2)

Second ventilatory drive

17
Q

What is hypercapnea?

A

Raised PCO2

18
Q

What change in blood PCO2 does hyperventilation cause

A

Reduces PCO2 - reduces CSF H+

Inhibits ventilation

19
Q

does the medulla respond to direct changes in the plasma H+?

A

No

20
Q

What crosses the blood brain barrier, PCO2 or H+?

A

PCO2

21
Q

What do the peripheral chemoreceptors cause?

A

Reflex stimulation of ventilation, following a SIGNIFICANT fall in arterial PO2 or rise in H+

22
Q

Dissociation of CO2 in water is - CO2 + H2O H2CO3 HCO3- + H+
Which direction does increased ventilation shift the equilibrium?

A

Increased ventilation drives this equation to the left (by blowing off CO2) and lowers [H+]

Decreased ventilation drives this equation to the right (by retaining CO2) and increases [H+]

23
Q

Which type of chemoreceptors afferent sensory neurones?

A

Carotid and aortic chemoreceptors

24
Q

who is ‘da bomb’?

A

Kitty don O’Leary

25
Q

What do the somatic motor neurones for inspiration and expiration innervate?

A

Inspiration - Scalene and sternocleidomastoid muscles, external intercostals, diaphragm

Expiration - Internal intercostals
Abdominal muscles

26
Q

What allows us to have a large degree of voluntary control over breathing

A

Descending neural pathways from cerebral cortex to respiratory motor neurones..

27
Q

Can cerebral coretex neural pathways override involuntary stimuli such as PCO2 or H+?

A

NO

28
Q

What are examples of voluntary control of ventilation?

A

Breath-holding

Hyperventilation

29
Q

What is the neurotransmitter that responds to low PO2 in the peripheral chemoreceptors?

A

DOPAMINE

30
Q

What type of drugs repress respiratory centre?

A

Barbituates and opiods

31
Q

What is the effect of anaesthetic agents?

A

Increases respiratory rate but decrease Tidal volume so decrease AV.

32
Q

What is the effect of nitrous oxide?

A

Sedative/light anaesthetic agent

Blunts peripheral chemoreceptor response to falling PaO2.

33
Q

When is nitrous oxide problematic?

A

Chronic lung disease cases where individuals often on hypoxic drive.

34
Q

What happens when you administer oxygen to patients with chronic lung disease?

A

Aggravates the situation

35
Q

Describe respiration during swallowing

A

Inhibited to avoid aspiration of food or fluids into the airways

36
Q

Why is swallowing followed by an expiration?

A

In order that any particles are dislodged outwards from the region of the glottis.