L15 Control of Ventilation

Question 1

Describe the DRG, including what it innervates, what it exerts is effect on and via what route?

Answer 1

Inspiratory neutrons that synapse with motor neurons (phrenic & intercostal) innervating the diaphragm –> construction

Question 2

Describe the VRG, including what it innervates, what it exerts is effect on and via what route?

Answer 2

Affects the accessory muscles of inspiration which function w/ increased exercise requirements (abdominal + intercostal)

Question 3

Describe the pre-Botzinger complex, including what it innervates, what it exerts is effect on and via what route?

Answer 3

synapses with dendrites from the DRG.
Tells DRG when to send muscles to diaphragm for contraction.

inhibition of AP from pre-botzinger complex would cause diaphragm relaxation

Question 4

Describe the pontine control of respiration, including the centres that it includes and their function

Answer 4

Pons includes apneustic centre and pneumotaxic centre.

Apneustic= fine tuning of breathing 
Pneumotaxic= terminates inspiration

Question 5

What is the function of the apneustic centre

Answer 5

fine tuning of breathing –> prevents switching off of inspiratory neurons

Question 6

What is the function of the pneumotaxic centre

Answer 6

termination of inspiration

Question 7

Describe 5x types of inputs/ courses that the DRG receives to convert into signals regulating ventilation

Answer 7

input from

1. apneustic centre for fine tuning
2. pneumotaxic centre to terminate inpiration
3. stretch receptors at airways that prevent over stretching of alveoli
4. Mechanoreceptors at airways for coughing and sneezing reflexes
5. Chemoreceptors (peripheral and central)

Question 8

Where are the peripheral chemoreceptors that regulate ventilation found?

Answer 8

carotid body (CNIX) and aortic arch (CNX)

Question 9

What is the effect of peripheral and central chemoreceptors on ventilation in response to a fall in PO2???

Answer 9

Perhipheral= stimulation 
central= no effect, but general depression of neural function

Question 10

What is the effect of peripheral and central chemoreceptors on ventilation in response to an increase in PO2???

Answer 10

peri= weak stimulation

central= strong stimulation due to inc [H+] in brain ECF

Question 11

What is the effect of peripheral and central chemoreceptors on ventilation in response to an increase in [H+]???

Answer 11

peripheral= stimulation

central= no effect

Question 12

What is the effect of peripheral and central chemoreceptors on ventilation in response to a fall in PCO2???

Answer 12

central= depression

Question 13

Out of O2, CO2 and H+, which crosses blood brain barrier?

Answer 13

not H+

Question 14

a decrease in arterial PO2 is also known as ____ drive

Answer 14

hypoxic

Question 15

an increase in PCO2 in also known as _____ drive

Answer 15

hypercapnic

Question 16

is the response strong in central or peripheral centres to a change on PCO2?

Answer 16

central –> important as CO2 diffuses across blood brain barrier. will increase ventilation to stimulate a release of CO2 from lungs

Question 17

and increase of H+ in blood is also known as ____ and will ____ ventilation

Answer 17

acidosis –> INC ventilation

Question 18

decrease in H+ in blood also known as _____ and will _____ ventilation

Answer 18

alkalosis –> DEC ventilation

Question 19

Why part of the “higher brain centre” contributes to conscious control of respiration

Answer 19

Cortical centre.

Stops breathing during swallowing, vocalisation, defecation, parturition.