Neural Generation Of Rhythmic Breathing

Question 1

What is inspiration initiated by?

Answer 1

A burst of action potentials in the spinal motor neurons to inspiratory muscles eg. Diaphragm (vagus nerve arises from C3,4&5)

Question 2

What causes expiration?

Answer 2

When action potentials cease, inspiratory muscles relax, expiration occurs as the elastic lungs recoil

Question 3

Where does the control of breathing reside primarily? And that’s the same area that contains the…….

Answer 3

In neurons in the medulla oblongata

Major cardiovascular control centers

Question 4

What are the 2 pontine (pons) centres?

Answer 4

Apneustic & pneumotaxic

Question 5

What do pons do?

Answer 5

Send rich synaptic input from pons to medulla

Question 6

Apneustic centre
Where is it found in pons?
What does it control?
Where does it send impulse to after?

Answer 6

Lower pons
Fine tunes inspiration (continues to activate inspiratory neurons to inhibit expiration)
Dorsal respiratory group DRG

Question 7

Pneumotaxic Centre
Where is it located?
What does it control?
Where does it send impulses to?

Answer 7

Upper pons
Smooth transition between inspiration and expiration
Ventral respiratory group (VRG)

Question 8

What can the pneumotaxic centre also do?

Answer 8

Override the activity of the apneustic centre

Question 9

What are the 2 main components of the medullary respiratory Centre?

Answer 9

Dorsal respiratory group (DRG)

Ventral respiratory group (VRG)

Question 10

What is the function of the dorsal respiratory group?

Answer 10

Inspiration
(Neurons fire during inspiration, activate respiratory muscles involved in resp, diaphragm & external intercostal muscles)

Question 11

What is the function of ventral respiratory group?

Answer 11

Expiration (inhibits inspiration)
Contains expiratory neurons, most important when large increases in ventilation are required eg - strenuous physical activity
Cause expiratory muscles to contract

Question 12

What is the other main complex of neurons in the respiratory Centre & what does it do?

Answer 12

The respiratory rhythm generator located in the pre - Bot zinger complex of neurons in the upper part of the VRG

Composed of pacemaker cells, sets the basal respiratory rate

Question 13

What happens during quiet breathing?

Answer 13

The respiratory rhythm generator activates inspiratory neurons in the VRG that depolarize the inspiratory spinal motor neurons resulting in inspiratory muscles contracting