Control of Respiration

Question 1

what has the main influence on breathing

Answer 1

CO2

Question 2

what is the pre-Botzinger group

Answer 2

pacemaker cells in superior ventral respiratory group that act as breathing rhythm generator

Question 3

what acts as the breathing rhythm generator

Answer 3

pre-Botzinger group

Question 4

what does the pons respiratory group do

Answer 4

regulates some normal discharges of breathing

Question 5

what are the 2 parts of the pons respiratory group

Answer 5

pneumotaxic and apneustic centres

Question 6

what does the pneumotaxic centre do

Answer 6

puts brakes on breathing

Question 7

what does the apneustic centre do

Answer 7

moderates effects of pneumotaxic centre - but can be overruled by pneumotaxic centre
stimulates DRG

Question 8

what is the role of the medulla oblongata in respiration

Answer 8

phasic discharge of action potential

Question 9

what are the 2 main groups of the medulla oblongata

Answer 9

dorsal respiratory group and ventral respiratory group

Question 10

what is the general structure of the DRG and VRG

Answer 10

bilateral

project into bulbo-spinal motor neuronpools and interconnect

Question 11

when is the DRG predominantely active

Answer 11

inspiration

Question 12

what does DRG stand for

Answer 12

dorsal respiratory group

Question 13

what is the DRG

Answer 13

group of inspiratory neurons in the medulla that stimulate diaphragm and external intercostals and send signals to VRG

Question 14

what does VRG stand for

Answer 14

ventral respiratory group

Question 15

when is the VRG active

Answer 15

inspiration (forced) and expiration

Question 16

what does the VRG do

Answer 16

stimulates accessory muscles of ventilation and inhibits apneustic centre

Question 17

what does the central pattern generator do

Answer 17

starts stops and rests background ventilatory drive

Question 18

is inspiration active or passive

Answer 18

active

Question 19

is expiration active or passive

Answer 19

mainly passive, with elastic recoil of thoracic wall

1st part involves active slowing with some inspiratory muscle activity

Question 20

what is minute ventilation

Answer 20

proportional to PaCO2

Inversly proportional to oxygen i.e.e 1/PaO2

Question 21

what is the value of minute ventilation

Answer 21

approx. 5l

Question 22

what do chemoreceptors sense

Answer 22

PaCO2

Question 23

what is the primary influence on brainstem chemoreceptors

Answer 23

PaCO2

Question 24

what influences carotid and aorta chemoreceptors

Answer 24

PaCO2, PaO2, pH

Question 25

where are central chemoreceptors found

Answer 25

in brainstem at pontomedullary junction - not DRG/VRG complex

Question 26

what do central chemoreceptors detect

Answer 26

H+ in CSF; present through dissociation of CO2 which diffuses through BBB

Question 27

what do central chemoreceptors do

Answer 27

provide excitatory synaptic input to the medullar inspiratory neurons

Question 28

what do peripheral chemoreceptors detect

Answer 28

O2, CO2, H+

Question 29

where are peripheral chemoreceptors found

Answer 29

bifurcation of CC arteries and arch of aorta

Question 30

are peripheral chemoreceptors the same as arterial baroreceptors

Answer 30

no - close but distinc

Question 31

where are carotid bodies found

Answer 31

common carotid arteries

Question 32

what are carotid bodies

Answer 32

main peripheral chemoreceptors involved in control of respiration

Question 33

what nerves are peripheral chemoreceptors linked to

Answer 33

CN 9 and 10 - send afferent fibres to higher brain centres

Question 34

what cells are present in peripheral chemoreceptors

Answer 34

specialised receptor cells that are mainly stimulated by a decrease in arterial pO2 and increase in arterial [H+]

Question 35

what does hypoxia do with peripheral chemoreceptors

Answer 35

type 1 cells release stored neurotransmitter that stimulates the carotid sinus neve and sends excitatory synaptic input to medullary inspiratory neurons

Question 36

what are the types of pulmonary receptors

Answer 36

slowly adapting stretch receptors rapidly adapting stretch receptors irritant receptors c-fibres J receptors (juxtapulmonary receptors)

Question 37

describe the properties of slowly adapting stretch receptors

Answer 37

myelinated | maintain a persistent or slowly decaying receptor potential during constant stimulus

Question 38

where are slowly adapting stretch receptors found

Answer 38

airway smooth muscle

Question 39

what activates slowly adapting stretch receptors

Answer 39

lung distention

Question 40

what is the Hering-Breuer reflex

Answer 40

reflex triggered to prevent over-inflation if lung - uses slowly adapting stretch receptors in airway smooth muscle

Question 41

what is the effect of activation of slowly adapting stretch receptors

Answer 41

high activity inhibits further inspiration this beginning expiration

Question 42

describe rapidly adapting stretch receptors

Answer 42

myelinated | generate a receptor potential and action potential at the onset of a stimulus - very quickly cease responding

Question 43

where are rapidly adapting stretch receptors found

Answer 43

between airway epithelial cells

Question 44

what activates rapidly adapting stretch receptors

Answer 44

lung distention and irritants - respond to rate of change in volume and irritants

Question 45

what do rapidly adapting stretch receptors do

Answer 45

produce brief burst of activity - high activity causes bronchoconstriction - may be involved in cough reflex

Question 46

where are irritant receptors found

Answer 46

larger conducting airways

Question 47

what are the properties of irritant receptors

Answer 47

rapidly adapting - cough, gasp

Question 48

describe c-fibres j receptors (juxtapulmonary receptors)

Answer 48

non-myelinated

Question 49

where are c-fibres J receptors (juxtapulmonary receptors) found

Answer 49

capillary walls or interstitium

Question 50

what activates c-fibres j receptors

Answer 50

increase in interstitial pressure (e.g. collection of fluid), irritants, lung volume, noxious agents

Question 51

what is the effect of c-fibre j receptor activation

Answer 51

rapid shallow breathing, bronchoconstriction, cardiovascular depression and dry cough