Physio 4

Question 1

what are the mechanisms for regulation of respiration

Answer 1

neural and chemical

Question 2

what are the neural mechanisms of regulation and by what

Answer 2

voluntary by cerebral cortex

involuntary by brainstem ( pons and medulla)

Question 3

what is the chemical regulation and by what

Answer 3

monitor o2 and co2 levels

by central and peripheral chemoreceptor

Question 4

what is the neural automatic mechanism to establish a rhythmic breathing pattern

Answer 4

medullary respiratory center

Question 5

what centers are present in medullary respiratory center

Answer 5

Dorsal respiratory group (DRG)
Ventral respiratory group (VRG)
Pneumotaxic center

Question 6

what does the ventral respiratory group responsible for (charac)

Answer 6

inspiratory and expiratory neurons
inactive during quiet breathing
active during active / forced respiration
stimulate expiratory signals to abdominal muscles

Question 7

what does the dorsal respiratory group responsible for (charac)

Answer 7

inspiratory neurons only
dormant during expiration
pacemaker
stimulate inspiratory muscles

Question 8

what does the pneumotaxic centern responsible for (charac)

Answer 8

sends impulses to DRG to switch off inspiratory neurons

control switch off point of inspiratory ramp so control duration of filling phase of lung cycle

Question 9

pneumotaxic signal strong

Answer 9

inspiration last for 0.5 sec so filling the lungs slightly

Question 10

pneumotaxic signal is weak

Answer 10

inspiration lasts for 5 sec so filling the lungs with excess air

Question 11

where is the chemosensitive area of respiratory center

Answer 11

beneath ventral surface of medulla

Question 12

what is the chemosensitive area sensitive to

Answer 12

changes in co2 and H+ ( h+ indirect and less effect)

Question 13

what is the respiratory reflex

Answer 13

rapid automatic adjustment in pulmonary ventilation

baroreceptor, stretch, chemoreceptor, irritating and others

Question 14

what is the stretch receptor

Answer 14

located in muscular portion of bronchi and bronchiole and it responds to changes in lung volume and send signals through vagus nerve to DRG

Question 15

What is the feedback response of stretch receptor

Answer 15

decrease inspiration when lung overinflated

Question 16

where is the central and peripheral chemoreceptors

Answer 16

central in medulla oblongata

peripheral in carotid and aortic arteries

Question 17

what do central and peripheral chemoreceptors detect and monitor

Answer 17

central detect ; interstitial co2 and monitor arterial co2 indirectly
peripheral detect; arterial co2 and monitor alveolar ventilation

Question 18

what is the main regulator of ventilation in central chemoreceptors

Answer 18

carbon dioxide generated H+

Question 19

What are peripheral chemoreceptors weakly and strongly responsive to

Answer 19

weakly ; arterial co2 changes

strongly ; increased arterial H+ conc

Question 20

what stimulates central and peripheral chemoreceptors

Answer 20

central : increase H+

peripheral : arterial PO2 below 60 mmhg

Question 21

peripheral chemoreceptor respond to changes of chemical content of arterial blood

Answer 21

true

Question 22

what causes hypercapnia and hypocapnia

Answer 22

hypercapnia by hypoventilation

hypocapnia by hyperventilation

Question 23

whhen PO2 levels below 60 mmhg what is triggered

Answer 23

respiratory center (DRG)

Question 24

When co2 levels rise by 10% what happens to RR

Answer 24

Doubled

Question 25

if PCO2 levels get too low what happens

Answer 25

unconsciousness

Question 26

where are baroreceptors located

Answer 26

aortic and carotid sinus

Question 27

what is baroreceptor reflex pathway

Answer 27

baroreceptors in aortic and carotid sinuses are monitored by sensory neurons in glossopharyngeal and vagus nerve then transmitted to respiratory center

Question 28

what happens in BP falls below normal

Answer 28

Respiratory center is stimulated

Question 29

respiration and BP have an inverse RS

Answer 29

true

Question 30

what is the protective reflex (irritant )

Answer 30

coughing or sneezing which is an apnea followed by forceful expulsion of air ( apnea ; period in which breathing has stopped )

Question 31

what is the inflation and deflation reflex activated by

Answer 31

stretch receptors in lungs during forced expiration ( TV above 1000ml)

Question 32

inflation reflex prevents what

Answer 32

overexpansion of lungs | inhibits inspiratory center and stimulate expiratory center

Question 33

deflation reflex inhibits and stimulates what

Answer 33

inhibits expiratory center and stimulate inspiratory center

Question 34

what is Hering Breuer reflex

Answer 34

Slowly adapting stretch R (SARs) located in bronchial airway only activated suring exercise to prevent excess lung inflation and terminate inspiration

Question 35

what is the apneustic center

Answer 35

stimulates inhalation by continuous stimulation of medulla oblongata send impulses to DRG to delay switch off signal of inspiratory ramp by pneumotaxic center

Question 36

what controls intensity of breathing and what controls the filling duration of lung cycle

Answer 36

intensity : apneustic center (sends positive impulses to inspiratory neurons) duration of filling : pneumotaxic center

Question 37

what inhibits apneustic center

Answer 37

pneumotaxic center

Question 38

location of baroreceptors, stretch receptors, chemoreceptors

Answer 38

baroreceptor ; carotid and aortic sinus stretch receptor in smooth muscles of bronchi and bronchiole central chemo; medulla peripheral chemo; aortic and carotid artery

Question 39

glossopharyngeal and vagus nerves involved in what reflex

Answer 39

baroreceptor

Question 40

vagus nerve involved in what reflex

Answer 40

stretch receptor