Breathing control

Question 1

What two groups of neurons in the medulla oblongata control breathing?

Answer 1

Dorsal respiratory group and ventral respiratory group?

Question 2

What other section of the brainstem, apart from the medulla oblongata, contains areas responsible for respiration control?

Answer 2

Pons

Question 3

What areas exist within the brainstem?

Answer 3

Midbrain, Pons, medulla oblongata

Question 4

What area is responsible for controlling the rate and depth of breathing, as well as feeding into the dorsal respiratory group?

Answer 4

Pneumotaxic centre

Question 5

What is the current known function of the apneustic centre?

Answer 5

Modulating the breathing cycle

Question 6

What area is responsible for initiating inspiration?

Answer 6

Dorsal respiratory group

Question 7

Where is the sensory terminal for the vagus (X) and glossopharyngeal (IX) nerves?

Answer 7

Nucleus tractus solitaris

Question 8

Where do the efferent (motor) signals from the dorsal respiratory group go?

Answer 8

To the inspiratory muscles

Question 9

How does the dorsal respiratory group allow for expiration?

Answer 9

There is an intense 2 second period of action potentials that trigger inspiration, followed by a rest period of 3 seconds to allow for expiration.

Question 10

True or false: during normal, quiet breathing, expiration is an active process

Answer 10

False, it is passive during quiet breathing and only becomes active when there is a need for extra respiratory drive.

Question 11

Describe the position of the ventral respiratory group in relation to the dorsal respiratory group

Answer 11

Anterior and lateral

Question 12

What process is the ventral respiratory group involved in?

Answer 12

Active breathing

Question 13

What types of receptors feedback to the respiratory centre about what is going on in the pulmonary system?

Answer 13

Chemoreceptors, mechanoreceptors, baroreceptors, thermoreceptors

Question 14

What part of the brain is involved in voluntarily holding your breath?

Answer 14

Cerebral cortex

Question 15

What centres in the brain may be involved in altering your breathing during emotional stimulus?

Answer 15

Hypothalamus and limbic system.

Question 16

What is the Hering-Breuer inflation reflex?

Answer 16

Stretch receptors in bronchial airways will signal to “turn off” inspiration drive when tidal volume reaches approximately 1.5L

Question 17

What are the two types of chemoreceptors?

Answer 17

Central and peripheral

Question 18

What vessel in the neck are peripheral chemoreceptors located, and what else is this location known for?

Answer 18

Carotid sinus, also where baroreceptors are located to monitor blood pressure

Question 19

Where can the carotid sinus be found?

Answer 19

Inferior to the bifurcation of the common carotid.

Question 20

What nerve carries signals from chemoreceptors in the carotid sinus?

Answer 20

Glossopharyngeal nerve (IX)

Question 21

From where does the vagus nerve (X) interact with peripheral chemoreceptors, and what is significant about this in humans?

Answer 21

Arch of the aorta, they are not used in humans as much as in other animals

Question 22

Which type of chemoreceptors are faster?

Answer 22

Peripheral

Question 23

What are the chemo sensitive cells of the carotid bodies called?

Answer 23

Type I glomus

Question 24

Which pH state are carotid body chemoreceptors more sensitive to?

Answer 24

Acidosis (High H+)

Question 25

What condition in the arterial blood will initiate the quickest and first response from carotid body chemoreceptors?

Answer 25

Hypercapnia

Question 26

Hypoxia can be recognised by carotid body chemoreceptors, describe the pitfalls of this mechanism if it were used solely to control respiration.

Answer 26

They are not sensitive to small decreases in PaO2. PaO2 can decrease to <60mmhg before ventilation is significantly increased.

Question 27

Why does ventilation decrease below a PaO2 of 30mmhg?

Answer 27

CNS depression

Question 28

Where are central chemoreceptors located?

Answer 28

0.2mm inferior to the ventral surface of the medulla oblongata

Question 29

Which type of chemoreceptors are most sensitive to PaCO2?

Answer 29

Central

Question 30

What fluid do the central chemoreceptors respond to?

Answer 30

CSF

Question 31

True or false: CO2 can diffuse across the blood brain barrier

Answer 31

True

Question 32

The stimulus of hypoxia and hypercapnia increase ventilation more together than alone, what is this called?

Answer 32

A synergistic effect

Question 33

What happens to the central chemoreceptors during COPD and why does this pose a risk when delivering high percentage O2?

Answer 33

Because of long-term hypercapnia, they become less sensitive to increases in PaCO2, and ventilation instead becomes reliant on the PaO2 levels in the carotid bodies. If high percentage oxygen is given, the respiratory drive of hypoxia is removed and ventilation decreases.