Control of Respiration

Question 1

what are some factors that modulate breathing

Answer 1

reflexes like coughing
vocalisation like singing
volitional control like holding the breath
emotional events like crying
physiological challenges like sleep and exercise

Question 2

what are the two signal senders to the brain in relation to breathing

Answer 2

chemoreceptors
mechanoreceptors

Question 3

what do chemoreceptors do in relation to breathing

Answer 3

provide feedback on partial pressures of oxygen and carbon dioxide, and pH

Question 4

what do mechanoreceptors do in relation to breathing

Answer 4

provide feedback on mechanical status of the lungs, chest wall and airways

Question 5

what do the chemoreceptors and mechanoreceptors send neural signals to

Answer 5

respiratory muscles and upper airway muscles. they also produce reflexes to keep airways patent like coughing and sneezing

Question 6

what do respiratory muscles do

Answer 6

they produce rhythmic breathing movements like diaphragm and intercostals

Question 7

what are the upper airway muscles

Answer 7

laryngeal
pharyngeal
tongue

Question 8

what are some reflexes to keep airways patent

Answer 8

coughing and sneezing

Question 9

where are many of the important neuronal cell groups found

Answer 9

in the brainstem

Question 10

what are chemoreceptors

Answer 10

sensory receptors that detect chemical changes in the surrounding environment

Question 11

what are peripheral chemoreceptors

Answer 11

small, highly vascularised bodies in the region of the aortic arch and the carotid sinuses

Question 12

how is the information from peripheral chemoreceptors sent

Answer 12

via glossopharyngeal and vagus nerves to the nucleus in brainstem called the NTS

Question 13

what is the NTS

Answer 13

the nucleus tractus solitatius

Question 14

label this

Answer 14

Question 15

what do peripheral chemoreceptors respond to

Answer 15

decrease in the partial pressure of oxygen

Question 16

what is the term for a decrease in partial pressure of oxygen

Answer 16

hypoxia

Question 17

describe the peripheral chemoreceptor pathway

Answer 17

reduction in arterial partial pressure
peripheral chemoreceptors stimulated
neural signals sent from the carotid and aortic bodies in the NTS in the brainstem
ventilation increases to restore the partial pressure of oxygen levels

Question 18

describe the ventilatory response to hypoxia

Answer 18

progressive reductions in inspired oxygen have little effect until about 60mmHg
below 60 there is progressive hyperventilation
hypoxic response originates in carotid and aortic bodies
play little part in the moment to moment control of breathing

Question 19

what are central chemoreceptors

Answer 19

central chemoreceptors are clusters of neurones in the brainstem that are activated when partial pressure of carbon dioxide is increased or pH is decreased

Question 20

what is the term for a increase in the partial pressure of carbon dioxide

Answer 20

hypercapnia

Question 21

describe the pathway of the central chemoreceptors when there is an increase in the partial pressure of carbon dioxide

Answer 21

the central chemoreceptors are stimulated
signals are processed and information is passed on to the neuronal clusters in the brainstem involved in generating breathing
ventilation increases to restore the partial pressure of carbon dioxide levels

Question 22

describe the ventilatory response to hypercapnia

Answer 22

very small changes in partial pressures of carbon dioxide have large effects on ventilation
hypercapnic response originates in the central chemoreceptors in the brainstem
plays a major role in the moment to moment control of breathing

Question 23

what are mechanoreceptors

Answer 23

sensory receptors that detect changes in pressure, movement and touch

Question 24

what do the mechanoreceptors detect in the respiratory system

Answer 24

movement of the lung and the chest wall ie during inspiration the mechanoreceptors detect inflation of lungs and movement of the chest

Question 25

describe the pathway of mechanoreception

Answer 25

inflation of lungs activates mechanoreceptors neural signals sent via the vagus nerve to the NTS in the brainstem ventilation is adjusted accordingly

Question 26

what are mechanosensory signals essential for

Answer 26

adapting and adjusting breathing integrating the respiratory pattern with other movements like posture and locomotion

Question 27

what is the location of respiratory mechanoreceptors

Answer 27

airway smooth muscle

Question 28

what is the reflex of the mechanoreceptors when there is inflation of the airways

Answer 28

termination of inspiration

Question 29

describe the pathway of respiratroy mechnoreceptors in the airway epithelium

Answer 29

they detect rapid lung inflation or deflation and lead to a sigh or shortened expiration

Question 30

what does the NTS do

Answer 30

receive information from mechanoreceptors and peripheral chemoreceptors

Question 31

what is the NTS

Answer 31

cluster of respiratory neurones in the brainstem that generate the rhythm of breathing. forms a vertical column of grey matter in the medulla oblongata of the brainstem.

Question 32

describe information processing in the NTS

Answer 32

processed by the neurones and sent to respiratory muscles

Question 33

when are inspiratory neurons active

Answer 33

during inspiration

Question 34

when are expiratory neurones active

Answer 34

during expiration

Question 35

what are the neurons found in the NTS

Answer 35

rhythm generating neurons that continue to produce a respiratory like rhythmic output when isolated

Question 36

describe the pathway of the output of signals from the brainstem to the respiratory muscles

Answer 36

neurons produce rhythmic output rhythmic neural signals sent to the spinal cord phrenic nerve exits the spinal cord from 3-5 phrenic nerve innervates the diaphragm nerves exit the thoracic spinal cord to innervate the intercostal muscles

Question 37

this is the medulla oblongata. label it

Answer 37

Question 38

describe high centre modulation of breathing

Answer 38

the high centres are the cerebral cortex, limbic system and the hypothalamus it has volitional and emotional control

Question 39

describe somatotopic organisation of the primary motor cortex

Answer 39

the area of the motor cortex dedicated to a particular muscle is proportional to the number of motoneurones innervating the muscle

Question 40

where are the respiratory rhthym generating neurones located

Answer 40

in the brainstem