control of breathing

Question 1

at rest what is the partial pressure of oxygen?

Answer 1

100mmHg

Question 2

at rest what is the partial pressure of CO2?

Answer 2

40mmHg

Question 3

what is breathing modulated by?

Answer 3

• reflexes (coughing)
• volitional control (breath hold)
• vocalisation (singing)
• physiological challenges (exercise)
• emotional events (crying)

Question 4

what is the name of normal rhythmic breathing?

Answer 4

eupnea

Question 5

what is the name for short breath?

Answer 5

dyspnea

Question 6

normal rhythmic breathing is controlled by what?

Answer 6

• respiratory related neutrons
• central pattern generators
• respiratory motor neurons

Question 7

what is the function of respiratory related neutrons (RRN)?

Answer 7

fire more APs during respiratory cycle

Question 8

what is the function of central pattern generators (CPG)?

Answer 8

in brainstem (medulla oblongata), independently generate respiratory rhythm

Question 9

what is the function of respiratory motor neurons?

Answer 9

innervate respiratory muscles, axons via phrenic nerve innervate diaphragm

Question 10

brain receives respiratory neural signals via?

Answer 10

chemoreceptors and mechanoreceptors

Question 11

what is the function of chemoreceptors in control of breathing?

Answer 11

detect chemical changes - feedback on blood partial pressure of oxygen and CO2 and blood pH

Question 12

what is the function of mechanoreceptors in control of breathing?

Answer 12

provide mechanical feedback on mechanical status of lungs, chest walls and airways

Question 13

what does the brainstem control?

Answer 13

• upper airway
• respiration
• temp
• HR
• BP

Question 14

what is the term for a decrease in oxygen?

Answer 14

hypoxia

Question 15

what is the term for an increase in CO2?

Answer 15

hypercapnia

Question 16

what are peripheral chemoreceptors?

Answer 16

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

Question 17

chemoreceptors in the aortic arch send info via which nerve?

Answer 17

vagus

Question 18

chemoreceptors in the carotid sinuses send info via which nerve?

Answer 18

glossopharyngeal

Question 19

peripheral chemoreceptors send info to which region of the brainstem?

Answer 19

NTS

Question 20

what are central chemoreceptors?

Answer 20

clusters of neurons in the brainstem that are activated when partial pressure of CO2 increases (hypercapnia) or pH decreases

Question 21

what is the effect of reduced partial pressure of oxygen on ventilation ?

Answer 21

little effect until PO2 drops to 60mmHg then there is progressive hyperventilation

Question 22

where does hypoxic response originate?

Answer 22

carotid and aortic bodies

Question 23

what is the result of increases PCO2 on ventilation?

Answer 23

small change in PCO2 has large effect of ventilation (unlike O2)

Question 24

where does hypercapnia response originate?

Answer 24

central chemoreceptors

Question 25

in the respiratory system, what do mechanoreceptors detect?

Answer 25

movement of lungs and chest wall

Question 26

describe the action of mechanoreceptors in respires to lunch inflation?

Answer 26

inflation of lungs activates mechanoreceptors, they send neural signals via the vagus nerve to NTS NTS then adjusts ventilation accordingly

Question 27

where may mechanoreceptors be found?

Answer 27

airway smooth muscle and airway epithelium

Question 28

where does the NTS receive info from?

Answer 28

peripheral chemoreceptors and mechaoreceptors

Question 29

information entering the NTS is processed by what?

Answer 29

respiratory neurons in the brainstem

Question 30

which neurons activate inspiration?

Answer 30

inspiratory neurons

Question 31

which neurons activate expiration?

Answer 31

expiratory neurons

Question 32

rhythmic signals are sent to which nerve in the spinal cord?

Answer 32

phrenic

Question 33

which nerve carrying rhythmic signals innervates the diaphragm?

Answer 33

phrenic

Question 34

where is the dorsal respiratory group and which type of neurons does it contain?

Answer 34

in NTS, contains mainly inspiratory neurons

Question 35

where is the ventral respiratory group and which type of neurons does it contain?

Answer 35

medulla oblongata in brainstem, both expiratory and inspiratory neurons and motor neurons

Question 36

which respiratory group modulates respiratory output?

Answer 36

pontine respiratory group

Question 37

which region of the brain controls voluntary actions which can alter airflow?

Answer 37

primary motor cortex