control of breathing

Question 1

what makes breathing a unique behaviour?

Answer 1

it is continuous from birth to death & occurs spontaneously

Question 2

what is eupnea?

Answer 2

normal rhythmic breathing

Question 3

what is dyspnea?

Answer 3

being short of breath, aware of difficult breathing

Question 4

what must neuronal control of breathing do?

Answer 4

establish automatic rhythm
respond to metabolic demands
respond to mechanical changes
range of episodic nonventilatory behaviours

Question 5

what are respiratory related neurons?

Answer 5

array of interconnected neurons, fire more APs during resp cycle

Question 6

what are central pattern generators?

Answer 6

in brainstem/medulla, independently generate respiratory rhythm

Question 7

what are respiratory motor neurons?

Answer 7

innervate resp muscles, axons via phrenic nerve innervate diaphragm

Question 8

how can frequency of resp CPG change?

Answer 8

strength from central and peripheral receptors, change both depth and frequency of ventilation

Question 9

where does the brain receive neural signals from?

Answer 9

chemoreceptors- blood PO3,PCO2 and pH

mechanoreceptors-mechanical status

Question 10

where are neural signals sent to?

Answer 10

resp muscles- produce rhythmic breathing movements, upper airway muscles, produce reflexes

Question 11

what are chemoreceptors?

Answer 11

sensory receptors that detect chemical changes in the surrounding environment

Question 12

what do chemoreceptors detect in the resp system?

Answer 12

changes in PO2, PCO2 and pH

Question 13

what responds to decreases in PO2 - hypoxia?

Answer 13

peripheral chemoreceptors

Question 14

how are normal PO2 levels restored?

Answer 14

peripheral chemoreceptors stimulated, neural signals sent from carotid and aortic bodies to NTS in brainstem, ventilation increases

Question 15

what are central chemoreceptors?

Answer 15

clusters of neurones in the brainstem that are activated when PCO2 is increased-hypercapnia, or pH decreased

Question 16

how are normal PCO2 levels restored?

Answer 16

central receptors stimulated, info passed on to neuronal clusters in brainstem involved in generating breathing, ventilation increase

Question 17

what is the effect of very small changes in PCO2 on ventilation?

Answer 17

large effects

Question 18

what are mechanoreceptors?

Answer 18

sensory receptors that detect changes in pressure, movement and touch

Question 19

what do mechanoreceptors detect in the resp system?

Answer 19

movement of lung and chest wall

Question 20

what are 3 functions of mechanoreceptors?

Answer 20

pulmonary stretch receptors detect lung vol/muscle length, can terminate inspiratory effort, can adjust ventilation for changes in posture

Question 21

how do mechanoreceptors adjust ventilation?

Answer 21

inflation activates them, neural signals sent via vagus nerve to NTS in brainstem, ventilation adjusted

Question 22

what is NTS?

Answer 22

nucleus tractus solitaries- receives info from mechanoreceptors and peripheral chemoreceptors, processed in brainstem by resp neurons

Question 23

what neurones are active during inspiration?

Answer 23

inspiratory neurones

Question 24

describe resp rhythm generating neurones in brainstem

Answer 24

bilateral cluster of neurons with rhythm generating properties

Question 25

where do rhythmic neural signals sent from brainstem?

and describe nerve innervation

Answer 25

spinal cord, phrenic nerve exits spinal cord at cervical cord level 3-5, phrenic nerve innervates diaphragm, nerves exiting thoracic spinal cord innervate intercostals

Question 26

what does the pontine respiratory group do?

Answer 26

modulates resp output

Question 27

what kind of neurons does the ventral resp group have?

Answer 27

inspiratory, expiratory and motor, regions which may be respiratory CPG

Question 28

describe the dorsal resp group

Answer 28

around the NTS, mainly inspiratory neurons, receives sensory info from all receptors, integration of sensory info from resp system

Question 29

which voluntary actions alter airflow?

Answer 29

breath holding, speaking, singing

Question 30

where do voluntary actions originate?

Answer 30

in motor cortex - control is precise

Question 31

how is control not absolute?

Answer 31

breath holding overridden by ventilatory drive from chemoreceptors