Physiology of Neural Control of Breathing

Question 1

What is the breathing rhythm generated by?

Answer 1

network of neurons called the Pre-Botzinger complex

Question 2

Describe the Pre-Botzinger complex?

Answer 2

Display pacemaker activity

They are located near the upper end of the medullary respiratory centre

Question 3

What is the main neural control/rhythm generator of respiration?

Answer 3

Medulla

Question 4

Name the steps of the Pre-Botzinger complex?

Answer 4

1. Excites Dorsal respiratory group neurones (inspiratory)
2. Fire in bursts
3. Firing leads to contraction of inspiratory muscles - inspiration
4. When firing stops, passive expiration

Question 5

What can the rhythm generated in the medulla be modified by?

Answer 5

neurones in the pons

Question 6

What effect does the apneustic center have on inspiration?

Answer 6

impulses from these neurones excite inspiratory area of medulla to prolong inspiration

Question 7

What do the peripheral chemoreceptors do and where are they located?

Answer 7

Sense tension of oxygen and carbon dioxide and [H+] in the blood.
They are located in the carotid and aortic bodies

Question 8

What do central chemoreceptors respond to and where are they located?

Answer 8

Respond to the [H+] of the cerebrospinal fluid (CSF). Situated near the surface of the medulla of the brainstem

Question 9

Which type of chemoreceptor detects hypercapnia (high CO2)?

Answer 9

central chemoreceptors

Question 10

Which type of chemoreceptor detects hypoxia (low O2)?

Answer 10

peripheral chemoreceptors
- Stimulated only when arterial PO2 falls to low levels (<8.0 kPa)

May become important in patients with chronic CO2 retention (e.g. patients with COPD)