L22: Modulation Of Respiratory Control

Question 1

What do chemoreceptors detect

Answer 1

Chemical changes in the blood

Question 2

What do mechanoreceptors detect

Answer 2

Changes in the irritation and distension of airways and lungs

Question 3

What are peripheral chemoreceptors

Answer 3

Sensory receptors that are located in the periphery i.e outside the central nervous system

Question 4

Where are the 2 major location of peripheral chemoreceptors

Answer 4

Carotid bodies

Aortic bodies

Question 5

What does peripheral chemoreceptors detect and respond to

Answer 5

Po2
Pco2
Ph

Question 6

Where exactly is the aortic bodies located

Answer 6

Aortic arch

Question 7

Where exactly is carotid bodies located

Answer 7

Bifurcation of the common carotid artery (in the neck) into external and internal common carotid artery

Question 8

Does carotid bodies or aortic have the major functional role in ventilators control

Answer 8

Carotid bodies

Question 9

What is the afferent nerve of the carotid body

Answer 9

Glossopharyngeal nerve

Question 10

What is the afferent nerve of the aortic body

Answer 10

Vagus nerve

Question 11

From the carotid and aortic body where does the vagus nerve and glossopharyngeal nerve (sensory nerves) go to

Answer 11

To NTS in the brainstem

Question 12

What is a sinus

Answer 12

A swelling that contains baroreceptors

Question 13

What are the sinuses located near the carotid and aortic bodies

Answer 13

Carotid sinus

Aortic sinus

Question 14

Which cells in the bodies detect the changes in the blood gas

Answer 14

Globular/ type 1 cells

Question 15

What happens to the firing of the carotid body as pao2 decreases

Answer 15

Increases

Question 16

What happens to the firing of carotid bodies when there is a high paco2 and ph (metabolic acidosis)

Answer 16

Increases more

Question 17

What is metabolic acidosis

Answer 17

An increases in H+ that is not related to co2 (breathing)

Question 18

Overall what are the 3 stimulus that the carotid body increases it firing and responce

Answer 18

Hypoxia
Hypercapnia
Metabolic acidosis

Question 19

What is the mechanism of sensing hypoxia in the carotid body

Answer 19

1) hypoxia acts on the mitochondria to inhibit oxidative phosphorylation (Electron transport chain)
2) atp production is reduced
3) amp increases
4) this is activated an enzyme called AMPK
5) AMPK inhibits pottassium channels on the type 1 cells in the carotid body
6) this leads to membrane depolarisation
7) voltage gated calcium channels open
8) neurotransmitters are released to synapses to induce an action potential to glossopharyngeal nerve

Question 20

What can a carotid tumour be a result of

Answer 20

Hypoxia

Question 21

Apart from peripheral chemoreceptors what are the other types of chemoreceptors found in the body

Answer 21

Central chemoreceptors

Question 22

Where are the central chemoreceptors located

Answer 22

Brainstem of the CNS

Question 23

Does central chemoreceptors respond to hypoxia

Answer 23

No

Question 24

What inhibits central chemoreceptors

Answer 24

Hypoxia

Question 25

What are central chemoreceptors sensitive to

Answer 25

Carbon dioxide

Question 26

What can pass through the blood brain barrier from the capillary bed to the chemoreceptors

Answer 26

Carbon dioxide (hypercapnia)

Question 27

What happens to carbon dioxide when it passes through the blood brain barrier into the medulla

Answer 27

Carbon dioxide reacts with water to give hydrogen and bicarbonate ions

Question 28

What stimulates the central chemoreceptors

Answer 28

Hydrogen ions from the reaction of carbon dioxide

Question 29

What happens when the central chemoreceptors are stimulated

Answer 29

It sends activity to the medullary respiratory neurones of DRG etc to adjust ventilation

Question 30

Does central chemoreceptors respond to metabolic acidosis

Answer 30

No it only responds to hypercapnia

Question 31

What is acclimatisation

Answer 31

Decrease in H+ in the CSF (brain) by active transport from blood to CSF and vice versa

Question 32

What membrane is between the CSF and arterial blood

Answer 32

Blood brain barrier

Question 33

What does blood brain barrier prevent

Answer 33

Ions and large polar molecules from entering the CSF

Question 34

What is respiratory acid change

Answer 34

Change in ph due to co2

Question 35

Does respiratory acid affect the ph of CSF

Answer 35

Yes because carbon dioxide can enter the CSF by passing the blood brain barrier

Question 36

Does metabolic acid affect the CSF ph

Answer 36

Not much because hydrogen ions cannot pass the blood brain barrier

Question 37

What happens when the CSF ph decreases

Answer 37

Alveolar ventilation increases

Question 38

Why does alveolar ventilation increase when ph of CSF decreases

Answer 38

To ventilate out carbon dioxide and return the ph back to normal

Question 39

When does alveolar ventilation increase the highest

Answer 39

Hypoxia and hypercapnia occurring at the same time

Question 40

Which gas controls pa02

Answer 40

Paco2

Question 41

What are the 3 types of mechanical receptors in the lung

Answer 41

Rapidly adapting irritant receptors Slowly adapting stretch receptors J-type or c-fibre receptors

Question 42

What do readily adapting irritant receptors respond to

Answer 42

Irritants that are inhaled

Question 43

What are the afferent nerve of the pulmonary mechanical receptros

Answer 43

Vagus nerve

Question 44

Where does the vagus nerve feed into in the brainstem after being activated

Answer 44

NTS then DRG

Question 45

What do mechanical receptors respond to

Answer 45

Foreign bodies Chemical irritants Immunologic challenges

Question 46

Where are rapidly adapting irritant receptors located

Answer 46

Between airway epithelial cells

Question 47

What does rapidly adapting irritant receptors cause

Answer 47

Cough Bronchoconstriction Hyperpnoea (increased ventilation) All this occurs to stop irritant getting any further into the lung

Question 48

Where are slowly adapting stretch receptors located

Answer 48

Between smooth muscle cells

Question 49

What activates slowly adapting stretch receptors

Answer 49

Stretch

Question 50

What does the slowly adapting stretch receptors cause once activated

Answer 50

Inhibit inspiration and promote expiration Bronchodilation Tachycardia

Question 51

Where does the vagus afferent nerve feed into in the brainstem

Answer 51

NTS

Question 52

What is the stimulus of j-type/ c fibre receptors

Answer 52

Increase in interstitial fluid

Question 53

Where are j-type/c-fibre receptors located

Answer 53

Area between alveolus and pulmonary capillary

Question 54

What does j-type/c-fibre receptors cause once activated

Answer 54

``` Apnoea Bronchoconstriction Increased mucus secretion Hypotension Bradycardia ```

Question 55

What is apnoea

Answer 55

Shallow breathing