Control of inhalation and exhalation

Question 1

What is Transpulmonary pressure?

Answer 1

The force acting to expand the lungs

Question 2

Describe the process of inhalation

Answer 2

Diaphragm stimulated to contract and flatten
Volume increases and pressure decreases (Boyle’s law)
Chest wall moves away from lung surface and parietal pleura moves away from visceral slightly
Transpulmonary pressure increases
Pressure enough to overcome elastic recoil
Lungs expand and air forced in

Question 3

Describe the key features of DRG

Answer 3

Rapid firing during inspiration

Input to the spinal nerves - in turn these control the diaphragm and intercostal muscles

Question 4

Describe the features of VRG

Answer 4

Sets the respiratory basal rate

Neurones fire in both inspiration and expiration

Question 5

What does DRG stand for?

Answer 5

Dorsal Respiratory Group

Question 6

What does VRG stand for?

Answer 6

Ventral Respiratory Group

Question 7

Where are the pontine systems found?

Answer 7

In the pons of the midbrain

Question 8

Where is the apneustic centre?

Answer 8

Area of the lower pons

Question 9

What is the role of the apneustic centre?

Answer 9

Helps to terminate inspiration by inhibiting neurones in the medullary inspiratory neuron output.

Question 10

Where is the pneumotaxic centre?

Answer 10

Area of the upper pons

Question 11

What is the role of the pneumotaxic centre?

Answer 11

Smooths the transition from inspiration and expiration

Also modulates activity of the apneustic centre