Control of Lung function Flashcards

1
Q

What are the different groups of neurones in the medulla?

A

Dorsal respiratory group
Ventral respiratory group
Apneustic centre
Pneumotaxic centre

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2
Q

What is the function of the dorsal respiratory group?

A

Inspiratory centre
Main ‘controller’ of inspiration
Set the ‘rate’

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3
Q

What is the function of the ventral respiratory group?

A

Expiratory centre
Inactive during quiet breathing
Inhibit apneustic centre

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4
Q

What is the function of the apneustic centre?

A

Stimulates activity in DRG

Inhibited by pulmonary afferents

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5
Q

What is the function of the pneumotaxic centre?

A

The ‘inspiratory off switch’

Regulates depth & frequency

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6
Q

What provides the main stimulus to breather

A

Proton concentration which is proportional to CO2 concentration

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7
Q

What are the main features of the irritant receptors?

A

Afferent receptors embedded within and beneath airway epithelium
Leads to cough: which involves forceful expiration against a closed glottis with sudden glottal opening & high velocity expulsion of air

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8
Q

What are the main features of stretch receptors?

A

Excessive inflation of lungs activates pulmonary stretch receptors
Afferent signals to respiratory centres inhibit DRG and apneustic centre and stimulate pneumotaxic VRG
Inspiration inhibited & expiration stimulated

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9
Q

What are the main features of J-receptors?

A

Sensitive to oedema and pulmonary capillary engorgement

Increases breathing frequency

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10
Q

What is an acid?

A

An acid is any molecule that has a loosely bound H+ ion that it can donate
H+ ions are also called protons (because an H atom with a +1 valency has no electrons or neutrons)

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11
Q

What is a base?

A

A base is an anionic (negatively charged ion) molecule capable of reversibly binding protons (to reduce the amount that are ‘free’)

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12
Q

Why might the acidity of the blood be tightly regulated?

A

Marked changes will alter the 3D structure of proteins

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13
Q

How does the blood regulate pH?

A

The blood has an enormous buffering capacity that can react almost immediately to imbalances

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14
Q

What is alkalaemia?

A

Refers to high-than-normal pH of blood

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15
Q

What is acidaemia?

A

Refers to lower-than-normal pH of blood

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16
Q

What is alkalosis?

A

Describes circumstances that will decrease [H+] and increase pH

17
Q

What is acidosis?

A

Describes circumstances that will increase [H+] and decrease pH

18
Q

What can changes in ventilation stimulate?

A

RAPID compensatory response to change CO2 elimination and therefore alter pH

19
Q

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

A

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

20
Q

What does acidosis need to correct?

A

Alkalosis

21
Q

What does alkalosis need to correct?

A

Acidosis

22
Q

Where are the peripheral chemoreceptors

A

Near the carotid baroreceptors (sensitive to changes in blood pressure?

23
Q

Describe what happens to breathing during exercise?

A

Efferents from primary motor cortex to gross skeletal musculature partly innervate medulla

Proprioceptive afferents from muscle spindles & golgi tendon organs innervate medulla on way to brain

24
Q

Describe the effects of skin afferents on breathing

A

Immersion in cold water
Inspiratory gasp
Hyperventilation