Physiology - Respiratory System: Control & Responses to Exercise

Question 1

Where are central chemoreceptors based in?

Answer 1

Respiratory centre.

Question 2

Where is the respiratory centre located?

Answer 2

Located in the medulla oblongata and pons, in the brainstem.

Question 3

What is the respiratory centre made up of?

Answer 3

• 3 major respiratory groups of neurones

- 2 in the medulla, 1 in the pons

Question 4

What is the respiratory centre responsible for?

Answer 4

Responsible for generating and maintaining the rhythm of respiration, and also of adjusting this in homeostatic response to physiological changes.

Question 5

Homeostasis?

Answer 5

The tendency to resist change in order to maintain a stable, relatively constant internal environment.

Question 6

Where are central chemoreceptors based?

Answer 6

Based in the respiratory centre.

Question 7

Central chemoreceptors?

Answer 7

They detect changes in the arterial partial pressure of carbon dioxide. When changes are detected, the receptors send impulses to the respiratory centre to restore normal partial pressure of carbon dioxide.

Question 8

pCO2?

Answer 8

Partial pressure of carbon dioxide.

The measure of carbon dioxide in the arterial or venous blood.

Question 9

(central chemoreceptors) As CO2 is produced it passes across…

Answer 9

the blood brain barrier and dissolves in CSF.

Question 10

CSF?

Answer 10

Cerebrospinal fluid.

Question 11

(central chemoreceptors) Blood is well buffered due to chemicals such as haemoglobin and plasma proteins, therefore…

Answer 11

little change in pH occurs during exercise.

Question 12

Buffered?

Answer 12

Moderates the impact of something.

Question 13

(central chemoreceptors) CSF is not well buffered, therefore…

Answer 13

pH falls when pCO2 increases.

Question 14

(central chemoreceptors) Fall in pH is sensed and…

Answer 14

stimulates breathing.

Question 15

The main drive for breathing is…

Answer 15

increased CO2, not lack of oxygen.

Question 16

Where are the peripheral chemoreceptors based?

Answer 16

• Carotid body

- Aortic bodies

Question 17

Function of peripheral chemoreceptors?

Answer 17

Detect changes in arterial blood oxygen and initiate reflexes that are important for maintaining homeostasis during hypoxemia.

Question 18

Hypoxemia?

Answer 18

Low level of oxygen in blood.

Question 19

What do the pons and medulla oblongata regulate? What can override this through voluntary control?

Answer 19

Inspiration & expiration.

Cerebral cortex.

Question 20

Where is the cerebral cortex located?

Answer 20

In the brain.

Question 21

What are the pons and medulla oblongata controlled by? What does it actively cause?

Answer 21

The inspiratory and expiratory centres.

Actively causes the contraction of the diaphragm during exercise and decreases the volume in the thorax.

Question 22

What is the inspiratory centre controlled by? What has a small input?

Answer 22

The central chemoreceptors.

Peripheral chemoreceptors.

Question 23

What informs the inspiratory centre that inspiration needs to be affected?

Answer 23

Active muscles.

Question 24

What drives the diaphragm and expands the external intercostal muscles to change the volume inside your lungs?

Answer 24

The inspiratory centre.

Question 25

What lets the expiratory centre know that expiration needs to occur?

Answer 25

Lung stretch receptors.

Question 26

Hering-Breuer reflex?

Answer 26

• Initiated by lung expansion/stretch receptors.
• Causes the relaxation of the intercostal & abdominal muscles.
• Shortens duration of inspiration.