Lecture 6 - Neural And Chemical Control Of Respiration Flashcards

1
Q

What part of the brain are the neurons supplying the diaphragm and intercostal muscles found?

A

Latter 2/3s of brainstem:
-Pons
-Medulla

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2
Q

Via what nerves do the neurones in the pons and medulla sent impulses to the primary respiratory muscles?

A

Phrenic nerves
Intercostal nerve

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3
Q

Look at the last slide and label the ventral viewe of the brain

A

1 = frontal lobe
2 = olfactory bulb
3 = optic chiasm
4 = optic nerve
5 = optic tract
6 = midbrain
7 = pons
8 = temporal lobe
9 = medulla oblongata
10 = cerebellum
11 = spinal cord

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4
Q

What are the 3 types of neurones involved in respiration?

A

Ventral group

Dorsal group

Pontine group

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5
Q

What does the ventral respiratory group of neurons control in respiration?

A

Expiration

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6
Q

What does the dorsal respiratory group of neurons control in respiration?

A

Inspiration

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7
Q

What does the pontine respiratory group of neurons control in respiration?

A

The rate and pattern of rhythm

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8
Q

What group of respiratory neurones spontaneously and continuously fire without needing sensory information?

A

Dorsal respiratory group neurons

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9
Q

What are the 2 groups of neurones that make up the Pontine Respiratory group?

A

Pneumotaxic center
Apneustic center

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10
Q

What is the function of the Pneumotaxic centre in the Pontine respiratory group of neurones?

A

Limits inspiration by restricting Action potential transmission in the phrenic nerve

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11
Q

What is the function of the Apneustic centre in the Pontine respiratory group of neurones?

A

Promotes inhalation by constantly sending signals to the medulla (dorsal group) delaying the inspiratory off switch

Controls the intensity of breathing

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12
Q

What inhibits the Apneustic centre?

A

Pulmonary stretch receptors

Pneumotaxic center

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13
Q

What part of the brain is responsible for voluntary breathing?

A

Motor cortex in the cerebrum

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14
Q

What are the 2 types of chemoreceptors?

A

Peripheral chemoreceptors

Central chemoreceptors

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15
Q

Where are peripheral chemoreceptors located?

A

Aortic bodies

Carotid bodies

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16
Q

What nerve does the peripheral chemoreceptors in the aortic body send impulses down?

A

Via Vagus Nerve (Cranial nerve X)

17
Q

What nerve does the peripheral chemoreceptors in the carotid body send impulses down?

A

Via Glossopharyngeal nerve (Cranial nerve IX)

18
Q

What do peripheral chemoreceptors detect?

A

Changes in partial pressure of Oxygen (pO2)

19
Q

What happens when peripheral chemoreceptors detect low levels of oxygen?

A

Respiratory rate and tidal volume increased

Blood flow directed to kidneys and brain

CO increased

20
Q

What type of cells are found in peripheral receptors?

A

Glomus

21
Q

What happens to the carotid body glomus cells are exposed to a low partial pressure of oxygen?

A

Membrane depolarises

Stimulates neurotransmitter and ATP release activates nerves (CNIX) and sends signals to CNS + stimulating respiration

22
Q

How does the nerve firing rate from carotid body nerves change as arterial paO2 increases and why?

A

Decreased impulses since respiration does need to be stimulated anymore

23
Q

What is the speed of the response from the peripheral chemoreceptors?

A

First chemoreceptor to respond (rapidly respond)

24
Q

What do peripheral chemoreceptors detect?

A

Changes in partial pressures of oxygen

25
Q

What do central chemoreceptors detect?

A

Changes in partial pressures of CO2

Cant detect Hypoxaemia

26
Q

Where are central chemoreceptors located?

A

Brain side of the Blood Brain Barrier

27
Q

What is the response to a sudden increase in pCO2?

A

Ventilation rapidly increases

28
Q

What part of the brain are central chemoreceptors in?

A

Medulla in brainstem

29
Q

How does changes in pCO2 affect pH of the CSF?

A

Small decrease in pCO2 leads to inc in PH of CSF which causes the resp centre to decrease its ventilation (less CO2 needs to be lost)

Small inc in pCO2 leads to dec in pH of CSF so resp centres inc vent rate

30
Q

What is the response to chronic hypercapnia when detected be central chemoreceptors?

A

Choroid plexus increases activate transport of HCO3- into the CSF

31
Q

What is the effect of stimulating stretch receptors in the smooth in the airways due to excessive stretching in the lungs during large inspirations?

A

Slows resp freq by increasing expiratory time

32
Q

What happens to CO2 levels in hypoventilation?

PH?

A

Hypercapnia since removal of CO is less than its production

The higher pCO2 leads to respiratory acidosis

33
Q

How does the body respond to low pH (respiratory acidosis)?

A

Kidneys reduce excretion of HCO3-

34
Q

What happens to pCO2 and pH with hyperventilation?

A

Removal of CO2 is more rapid than its production
PH rises (Respiratory alkalosis)