21 Control of breathing

Question 1

What are the two key tasks in breathing?

Answer 1

-Establishing automatic rhythm
-Adjusting that rhythm to accommodate:
metabolic changes
mechanical/postural changes
episodic non ventilator behaviour (speaking/sneezing)

Question 2

under normal conditions in the lungs:

Answer 2

O2 absorption matches delivery

CO2 production matches removal

Question 3

How is the balance in O2 and CO2 absorption/delivery and generation/removal achieved?

Answer 3

Locally - changes in blood flow and O2 delivery

Centrally - changes in depth and rate of respiration

Question 4

What happens in the alveoli when there are areas of high CO2 partial pressure?

Answer 4

Bronchodilation so increased airflow to that area. CO2 has a direct effect on the smooth muscle

Question 5

What are the different types of receptors involved in the control of breathing?

Answer 5

Central chemoreceptors (brain, pons and medulla)
Peripheral chemoreceptors
Mechanoreceptors

Question 6

What do the central chemoreceptors detect?

Answer 6

• Changes in pH

- Hypercapnia (CO2 retention)

Question 7

What do the peripheral chemoreceptors detect? (found in aorta and carotid body)

Answer 7

(found in aorta and carotid body)

• Changes in pH
• Hypercapnia
• Hypoxia