Control of respiration

Question 1

What is the function of the medulla in respiration?

Answer 1

It is the primary respiratory control centre and sends signals to the muscles that control respiration.

Question 2

What is the function of the pons in respiration?

Answer 2

Another respiratory control centre located beneath the medulla. It controls the rate/ speed of respiration.

Question 3

What are the centers in the medulla and pons that regulate breathing?

Answer 3

Pons : pontine respiratory group made up of 2 areas; the pneumotaxic center and the apneustic center.

Medulla: the dorsal respiratory group and the ventral respiratory group.

Question 4

What does the pneumotaxic area do and where is it located?

Answer 4

Located in the upper pons

It sends signals to inhibit inspiration to allow expiration to occur

Question 5

What does the apneustic centre do and where is it located?

Answer 5

Located in the lower pons

It sends signals to inhibit expiration by activating inspiratory neurones.

It increases tidal volume.

Question 6

What can the pneumotaxic area override?

Answer 6

The apneustic area.

Question 7

What is tidal volume?

Answer 7

The volume of air moved into or out of the lungs during normal, quiet breathing.

Question 8

Describe the dorsal respiratory group…

Answer 8

Inspiratory centre located in dorsal medulla
It sets the basic rhythm of breathing

Question 9

Describe the ventral respiratory group…

Answer 9

Expiratory centre located in ventral medulla
Active in both inspiration and expiration
Provides high respiratory drive when breathing needs to be increased. (exercise)

Question 10

Which centre sends signals to diaphragm to contract?

Answer 10

Dorsal respiratory group

Question 11

Where are central chemoreceptors located?

Answer 11

Medulla oblangata.

Question 12

What stimulates central chemoreceptors?

Answer 12

Stimulated by [H+] concentration and gas partial pressures in arterial blood
Brainstem [primary influence is PaCO2]

Question 13

Where are peripheral chemoreceptors located?

Answer 13

Carotid [(IX) cranial nerve afferents]
and aortic bodies [Vagal (X) nerve afferents].

Question 14

What stimulates peripheral chemoreceptors?

Answer 14

A decrease in PaCO2.

Question 15

What are peripheral chemoreceptors function?

Answer 15

Responsible for [all] ventilatory response to hypoxia (reduced PaO2)

When exposed to hypoxia, type I cells release stored neurotransmitters that stimulate the cuplike endings of the carotid sinus nerve

Question 16

Describe mechanoreceptors…

Answer 16

Located in the airway, trachea, lung, and pulmonary vessels.

They provide sensory information to the respiratory center in the brain with regards to lung volume, airway stretch, and vascular congestion.

Question 17

What are the 3 types of lung receptors (mechanoreceptors)?

Answer 17

Stretch
J receptors
Irritant

Question 18

Where are SASR (slow adapting stretch receptors) located?

Answer 18

Found in smooth muscle around airways.

Question 19

What activates SASR?

Answer 19

Lung distension

Question 20

How do SASR respond to activation?

Answer 20

They inhibit inspiration and so promote expiration.

Question 21

Where are RASR (rapidly adapting stretch receptors) located?

Answer 21

Between airway epithelial cells.

Question 22

What activates RASR?

Answer 22

Lung distension and irritants.

Question 23

How do RASR respond to activation?

Answer 23

Bronchoconstriction - narrowing of the airways

Question 24

What activates C fibres J receptors?

Answer 24

Increased interstitial fluid volume.

Question 25

How do C fibres J receptors respond to activation?

Answer 25

They cause rapid, shallowing breathing. Bronchoconstriction and cardiovascular depression.

Question 26

Is respiratory compensation fast or slow?

Answer 26

FAST!

Question 27

Why does respiration stop when swallowing?

Answer 27

protecting against the risk of aspiration of food or liquid

Question 28

Briefly describe the controller-effector-sensor loop.

Answer 28

The sensor detects a change (hypoxia), sends signals along the afferent pathway to the controller. The controller then sends signals along the efferent pathway to the effector. The effector responds.