respiratory 4

Question 1

what generates respiratory rhythm

Answer 1

medullary respiratory centres

Question 2

medullary respiratory centres receive input from

Answer 2

chemoreceptors
proprioceptors
airway receptos
hah centres

Question 3

depth is determined by

Answer 3

depth is determined by how actively the respiratory centre stimulates the respiratory muscles

Question 4

timing is determined by

Answer 4

when, and low long the respiratory centre is active

Question 5

how many respiratory ce3ntres

Answer 5

5

Question 6

respiratory centres

Answer 6

2 in the pons - pneumotaxic and apneustic

3 in the medulla - ventral and dorsal, and pre-botszinger

Question 7

pre-botzinger complex

Answer 7

the pacemaker
for quiet tidal breathing
spontaneously discharging neuron

Question 8

pre botzinger complex talks to

Answer 8

dorsal respiratory group which controls the phrenic nerve

emits repetitive bursts of inspiratory actin potentials - once these stop, expiration can happen

Question 9

basic rhythm of quiet tidal breathing

Answer 9

when inspiratory area is active, diaphragm actively contracts

Question 10

dorsal respiratory group receives input from

Answer 10

higher centres
pontine centres (bpneustic/pneumitaxic)
CNS and peripheral chemoreceptors
respiratory muscles

Question 11

forced breathing

Answer 11

involves different inspiratory and expiratory muscles (not just phrenic nerve)
so Ventral respiratory centre does this

Question 12

Ventral respiratory centre

Answer 12

inactive during quiet breathing
extra respiratory drive
contribute to expiration (major) and inspiration
NB during heavy exercise

Question 13

pontine respiratory centres

Answer 13

influence/modify prebot/DRG?VRRG activity

coordinatore transition between inhalation and exhalation - smooth out transitions

Question 14

apneustic area

Answer 14

inhibits inspiratory switch off - prolongs inspiration

longer inspiratory reduces respiratory frequency and increases depth

Question 15

pneumotaxic area

Answer 15

limits inspiration

this increases respiration rate and decreases depth

Question 16

decreased blood pH Amy indicate

Answer 16

CO2 retention
accumulation of lactic acid
excess ketone bodies (eg. diabetes mellitus)

Question 17

how does pH effect respiration

Answer 17

CO2 receptors are next to the respiratory centres
direct pH in cerebrospinal fluid - medullary control
peripheral receptors - in arterial blood, only used when arterial blood has really low oxygen

Question 18

central chemoreceptors

Answer 18

beneath ventral surface of the medulla
excites other portions of the respiratory centres - increase rate and depth of breathing
highly sensitive to changes in either CO2 or H+ in CSF

Question 19

how does CSF get acidic

Answer 19

CO2 diffuses across the blood brain barrier, H+ does not
carbonic anhydrase is on the medulla surface
this converts CO2 into carbonic acid which liberates protons

Question 20

regulation of ventilation

Answer 20

peripheral chemoreceptors
located in the carotid and the aorta arteries
specialised cells that sense hypoxaemia (major)
can also be affected by pH, pCO2, and temperature sensitive (minor)

Question 21

aortic bodes

Answer 21

peripheral chemoreceptor
on aorta
send sensory info to medulla through vagus nerve

Question 22

carotid bodies

Answer 22

peripheral chemoreceptor
at fork of common carotid artery
send info mainly through glossopharyngeal nerve

Question 23

peripheral chemoreceptors react to

Answer 23

pO2

don’t get triggered until arterial pO2 in 60mmHg - severe hypoxaemia

Question 24

hypothalamus and limbic system influence

Answer 24

modify rate/depth
eg. breath holding in anger or gasping in pain
increases in body temp cause increase in response rate
cortical controls - direct signals from the cerebral motor cortex that bypass medullary controls eg. voluntary breath holding

Question 25

vagal airway receptors

Answer 25

upper

sense flow, temperature, pressure, muscle contraction, obstruction

Question 26

myelinated pulmonary receptors

Answer 26

middle airway receptors

mechanoirritant - respond to irritation of the airways by initiating cough reflex or bronchoconstriction

Question 27

non myelinated pulmonary receptors

Answer 27

lower receptors
stimulated by chemicals
airway defines reflexes - tachypnoea, mucous secretion

Question 28

inflation reflex

Answer 28

hiring-breuer reflex
stretch receptors in airways that are dominant regulator of breathing
inhibitory signals to the medullary centres to end inhalation
acts as a protective response to prevent over inflation

Question 29

cough reflex

Answer 29

larynx, carina, bronchi and trachea are very sensitive to light touch

1. inspire
2. close epiglottis, shut vocal cords
3. contract abdominal/intercostals
4. open epiglottis and vocal cords
5. air explodes out and carries foreign matter

Question 30

respiratory adjustments

Answer 30

adjustments are geared to intensity and duration
brain - psychological stimuli - anticipation of exercise, cortical motor activation
proprioceptor impulses