Drive - receptors

Question 1

What is the role of receptors in the pharynx?

Answer 1

To stop respiratory activity during swallowing - protecting against aspiration of food or liquid

Question 2

Where/in what are slowly adapting stretch receptor found?

Answer 2

Airway smooth muscle

Question 3

What are slowly adapting stretch receptors activated by?

Answer 3

Lung distension

Question 4

Where/in what are rapidly stretch receptors found?

Answer 4

Between airway epithelial cells

Question 5

What are rapidly adapting stretch receptor activated by?

Answer 5

Lung distension and irritants

Question 6

What are receptors in the pharynx activated by?

Answer 6

Swallowing

Question 7

In slowly adapting stretch receptors how long are the action potentials initiated in afferent neutrons?

Answer 7

For the duration of the stimulus

Question 8

In rapidly adapting stretch receptors how long are the action potentials initiated in afferent neutrons?

Answer 8

At the onset of the stimulus but very quickly cease responding

Question 9

Where are C fibres J receptors found?

Answer 9

In either capillary walls and the interstitium

Question 10

For slowly adapting stretch fibres, rapidly adapting stretch fibres and C fibres J receptors say which are myelinated and which are not.

Answer 10

Slowly adapting stretch fibres = myelinated

Rapidly adapting stretch fibres = myelinated

C fibres J receptors = non-myelinated

Question 11

What are C fibres J receptors stimulated by?

Answer 11

An increase in lung interstitial pressure (caused by the collection of fluid in the interstitium)

Question 12

What is ventilatory drive extremely sensitive to?

Answer 12

Arterial partial CO2 pressure (particularly of blood entering the brain as it triggers central chemoreceptors)

Question 13

What is hypoxia?

Answer 13

A deficiency of oxygen at tissue level

Question 14

What is hypercapnia?

Answer 14

Carbon dioxide retention and arterial partial CO2 pressure.

Question 15

What categorises respiratory failure as type 1?

Answer 15

pO2 = low
pCO2 = low or normal

Question 16

Name a common cause of type 1 respiratory failure:

Answer 16

Pulmonary embolism

Question 17

What categorises respiratory failure type 2?

Answer 17

pO2 = low
pCO2 = high

Question 18

Name a common cause of type 2 respiratory failure:

Answer 18

Hypoventilation

Question 19

Describe the process that occurs when acetylcholine binds to the M3 receptor: (6)

Answer 19

1) acetyl choline binds to the M3 receptor
2) Receptor couples with Gq protein
3) Gq protein activates phospholipase C
4) Phospholipase C catalyses the breakdown of a plasma membrane phospholipid to DAG and IP3.
5) DAG acts as a second messenger and activates a family of proteins known as protein kinase C
6) IP3 binds to ligand-gated Ca2+ receptors located on the endoplasmic reticulum in bronchial. Which then open resulting in the release of Ca2+ which then stimulates bronchoconstriction

Question 20

Describe the process that occurs when noradrenaline binds to the G couple protein receptor: (5)

Answer 20

1) noradrenaline binds to receptor
2) Receptor couples with Gs protein
3) Gs protein adrenyl cyclase
4) Adrenyl cyclase then catalyses the conversion of cytosolic ATP to cyclic AMP (cAMP)
5) cAMP then acts as a second messenger then diffuses in the resulting in a decrease in Ca2+ concentrations resulting in bronchodilation.

Question 21

What does an agonist receptor ligand do?

Answer 21

Binds to a receptor and activates it (affinity and efficacy)

Question 22

What does an antagonist receptor ligand do?

Answer 22

Binds to a receptor (competitively inhibiting the agonist) but does NOT activate it (affinity but zero efficacy)

Question 23

What is measured by the term affinity?

Answer 23

The degree to which a particular messenger binds to its receptor

Question 24

What is measured by the term efficacy?

Answer 24

How well a ligand activates a receptor (how large the conformational change in shape is)