Control of Lung Function Flashcards

1
Q

What are the four centers in the brain that control lung function called?

A
  1. Dorsal Respiratory Group
  2. Ventral Respiratory Group
  3. Apneustic Center
  4. Pneumotaxic Center
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2
Q

What is the Dorsal Respiratory group responsible for?

A

it is the main controller of inspiration

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3
Q

Which group in the medulla sets the rate for inspiration?

A

The dorsal respiratory group

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4
Q

Which group in the medulla is the expiratory center?

A

The ventral Respiratory group

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5
Q

What does the ventral respiratory group Inhibit?

A

The Dorsal and The Apenustic

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6
Q

what does the Apneustic center do?

A

Stimulates the Dorsal Respiratory group

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7
Q

What is the pneumotaxic center known as?

A

The inspiratory off switch

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8
Q

What does the pneumotaxic center do?

A

Regulates depth and frequency of breathing

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9
Q

What does the pneumotaxic center inhibit?

A

The dorsal respiratory group

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10
Q

Why is the pneumotaxic center especially important?

A

Prevents pulmonary damage and over inflation of the lungs

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11
Q

Which two centers make up the pontine respiratory group?

A

The apnuestic center and the pneumotaxic center

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12
Q

Which muscles does the Dorsal Respiratry group Innervate?

A

The external Intercostals

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13
Q

Which muscles are involved with expiration?

A

Internal intercostals

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14
Q

Which muscles are involved with inspiration?

A

External Intercostals

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15
Q

Aside from the external intercostals, what else is involved with inspiration?

A

The diaphragm - It moves down during inspiration to reduce pressure in the lungs, which allows the flow of air into the lungs

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16
Q

Aside from the internal intercostals, what else in involved with inspiration?

A

Accessory Respiratory Muscles

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17
Q

Which anatomical structure(s) create the primary drive to breathe?

A

Specialised medullary/pontine nucleii

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18
Q

What inhibits the apneustic center?

A

Pulmonary afferents

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19
Q

What type of gap junctions do normal capillaries have?

A

H2O Filled Gap Junctions

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20
Q

What type of junctions are found in the Blood Brain Barrier?

A

Tight junctions

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21
Q

Why can charged or large molecules not pass through the blood brain barrier?

A

Due to the presence of tight junctions

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22
Q

Why can Carbon Dioxide pass the Blood Brain Barrier?

A

CO2 is highly lipid soluble and therefore can pass the blood brain barrier

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23
Q

Why are the tight junctions found in the brain?

A

Certain nervous cells like astrocytes pack the H2O filled junctions which make them tight junctions

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24
Q

Levels of Oxygen are sensed by what on the surface on the medulla oblongata?

A

Central Chemoreceptors

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25
Q

Where are central chemoreceptors found?

A

In the medulla oblongata

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26
Q

what do central chemoreceptors respond to?

A

Hydrogen ion concentration from the dissociation of CO2 within the surrounding tissue and the CSF, NOT BLOOD

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27
Q

Why do central chemoreceptors not response to changes in the blood?

A

The diffusion of the ions such as H+ and HCO3- from the blood is poor due to the tight junctions between the cells which forms the blood brain barrier

28
Q

Where are peripheral receptors located>

A

Around the aortic arch and the carotid sinus (Aortic and Carotid Bodies)

29
Q

Afferent neurones from the peripheral chemoreceptors are via which two nerves?

A

Glossopharyngeal and the Vagus nerve

30
Q

What enzyme is responsible for converting H2O and CO2 into H2CO3 and then H+ and HCO3-?

A

Carbonic anhyrase

31
Q

What happens when central chemoreceptors found in the medulla detect a reduced blood pH?

A

They cause the respiratory centers to increase the rate and depth of breathing

32
Q

How does the partial pressure of Carbon Dioxide change going from Rest into Exercise?

A

Does not change

33
Q

Why does the transition from rest to exercise not impact the partial pressure of CO2?

A

The overall affect is no change

34
Q

What are irritant receptors?

A

Afferent receptors found within and beneath airway epithelium

35
Q

What does activation of irritant receptors lead to?

A

Cough

36
Q

What does a cough involve?

A

which involves forceful expiration against a closed glottis with sudden glottal opening & high velocity expulsion of air

37
Q

What does excessive inflation of the lungs activate?

A

Pulmonary Stretch Receptors

38
Q

What does activation of the stretch receptors do?

A

Inhibits Inspiration and Stimulates expiration

39
Q

When stretch receptors are activated, which centers are activated and which are inhibited?

A

Apneustic and Dorsal and inhibited, and Ventral is stimulated

40
Q

What are J receptors sensitive to?

A

Pulmonary capillary engorgement and Oedema

41
Q

What does stimulation of the J receptors lead to?

A

Increased breathing Frequency

42
Q

What is Volitional Apnoea?

A

Cessation of breathing

43
Q

What is meant by chloride shift?

A

Where one chloride ion is exchanged into red blood cell for one bicarbonate ion out the red blood cell

44
Q

What is an acid

A

A proton donor

45
Q

A greater H+ concentration refers to what in terms of pH?

A

A low pH

46
Q

Why must the acidity of the blood be tightly regulated?

A

marked changes will alter the 3D structure of proteins (enzymes, hormones, protein channels)

47
Q

What transporter is involved in chloride shift?

A

AE1 Transporter

48
Q

What is the ability of the blood to react to changes in H+ ion conc known as?

A

buffering capacity

49
Q

What is meant by alkaemia?

A

A higher than normal pH of blood

50
Q

What is meant by acidaemia?

A

A lower than normal pH of blood

51
Q

What is alkalosis?

A

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

52
Q

What is acidosis?

A

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

53
Q

What stimulates a rapid compensatory response to affect pH?

A

Changes in ventilation

54
Q

What stimulates a slow compensatory response to affect pH?

A

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

55
Q

What is needed to correct an acidaemia?

A

Alkalosis

56
Q

What are baroreceptors?

A

Receptors which are sensitive to changes in blood pressure

57
Q

What receptors are involved in the control of alveolar ventilation during exercise?

A

Central chemoreceptors

58
Q

What triggers the change in ventilation due to emotional change?

A

The respiratory control center

59
Q

Efferents from primary motor cortex to gross skeletal musculature partly innervate what?

A

the medulla

60
Q

What innervates the medulla on the way to the brain during exercise?

A

Proprioceptive afferents from the muscle spindles and golgi tendon organs

61
Q

What effect does cycling someones legs have?

A

Increases ventilation - This shows that the afferent nerves from muscles and tendons also innervate the medulla on the way to the brain, as just through shortening and lengthening of the muscle fibres is enough to create an increase in ventilation

62
Q

What effect does immersion in cold water have on ventilation?

A

Results in an inspiratory gasp and hyperventilation

63
Q

What pH range is the blood pH tightly regulated between?

A

7.35 and 7.45

64
Q

What do peripheral chemoreceptors do?

A

They respond to changes in blood molecule concentrations (like oxygen and carbon dioxide) and help maintain cardiorespiratory homeostasis

65
Q

Why does the partial pressure of carbon dioxide and oxygen not change during normal exercise?

A

use of oxygen increases and prouction of CO2 increases, however this is compensated for by corresponding increases in ventilation such that blood gas levels remain in normal limits

66
Q

In what circumstance might the partial pressure of oxygen or carbon dioxide change?

A

During strenuous exercise, when the production of lactic acid results in an acideamia