L25: Regulation of Respiration

Question 1

purpose of medullary respiratory centers in brainstem

Answer 1

initiate breathing
located in reticular formation of medulla

broken into a dorsal and ventral group

Question 2

location and purpose of dorsal respiratory group

Answer 2

in nucleus of the tractus solitarius — aka dorsal part of medulla

sets basic rhythm of respiration

Question 3

the nucleus of tractus solitarius is the termination of ?

Answer 3

vagal and glossopharyngeal nerves

Question 4

the dorsal respiratory group receives info from ?

Answer 4

peripheral chemoreceptors
baroreceptors
some receptors in lungs

Question 5

which respiratory groups is mainly associated w/ inspiration and establishes the ramp signal

Answer 5

dorsal respiratory group

Question 6

location of VRG

Answer 6

in ventrolateral medulla

Question 7

rostral part of VRG

Answer 7

the botzinger complex

Question 8

the intermediate portion of the VRG is associated w/ ?

Answer 8

dilation of upper airway during inspiration

Question 9

neurons of caudal region of VRG, synapse w/ ?

Answer 9

motor neurons to muscles of forced expiration

mainly internal intercostals

Question 10

neurons of VRG are totally inactive during?

Answer 10

normal quiet respiration

do not participate in basic rhythm oscillation that controls respiration

Question 11

location of pontine respiratory group

Answer 11

2 centers in 2 areas w/in the pons

apneustic center = inferior pons

Pneumotaxic center = superior pons

Question 12

what are the 2 components of the pontine respiratory group

Answer 12

apneustic center

Pneumotaxic center

Question 13

apneustic center

Answer 13

function to limit lung expansion

loss of function = prolonged inspiratory gasps

Question 14

apneusis

Answer 14

prolonged inspiratory gasps

Question 15

Pneumotaxic center

Answer 15

primary function = control switch-off point of inspiratory ramp

controls rate of depth of breathing

Question 16

the Pneumotaxic center transmits signals to inspiratory center ?

Answer 16

dorsal respiratory group

Question 17

strong vs weak PRG signals

Answer 17

strong = 30-40 breaths/min

weak = 3-5 breaths/min

Question 18

pre-botzinger complex

Answer 18

small area of botzinger complex

generates timing of respiratory rhythm
generates pattern

decides length of inspiration/expiration

Question 19

botzinger complex

Answer 19

anterior part of VRG

may be associated w/ coordinating VRG output

Question 20

which respiratory group establishes the ramp signal?

Answer 20

dorsal respiratory group

Question 21

ramp signal

Answer 21

nervous signals transmitted to the inspiratory muscles - mainly diaphragm

Question 22

ramp signal volume

Answer 22

begins weakly
increase steadily for 2 sec
cease abruptly for 3 sec

rate of increase is rapid during heavy respiration

Question 23

why does the ramp signal cease abruptly?

Answer 23

to allow for elastic recoil of lungs and chest wall

aka expiration

Question 24

what is the usual method for controlling the rate of respiration?

Answer 24

control limiting point is at which ramp signal suddenly ceases

Question 25

what is the function of the hering-breuer inflation reflex ?

Answer 25

a proactive mechanism to prevent excess inflation of the lungs

Question 26

where does the hering-breuer inflation reflex begin?

Answer 26

stretch receptors in muscular portions of walls of bronchi/bronchioles signals sent to DRG causing inspiratory ramp ceased

Question 27

define apneusis

Answer 27

failure to turn off inspiration resulting in long inspiratory gasps

Question 28

loss of function of which respiratory centers leads to apneusis?

Answer 28

apneustic center of the pontine respiratory group that limits lung expansion

Question 29

define hypercapnia

Answer 29

increase in CO2 levels

Question 30

define hypoxia

Answer 30

decrease in O2 levels

Question 31

decreased activity in chemoreceptors is counterproductive why?

Answer 31

it would result in a decrease in gas exchange

Question 32

when do chemoreceptors increase their activity?

Answer 32

increase their rate of activity when toxic conditions occur hypercapnia/hypoxia

Question 33

chemoreceptors are exposed to ______ blood not ______.

Answer 33

arterial not venous

Question 34

what ions are mainly responsible for regulating ventilation at sea level

Answer 34

pCO2 and H+ ions pO2 between 60 - 80 mmhg

Question 35

location of central and peripheral chemoreceptors

Answer 35

central -- ventral surface of medulla peri -- in aortic arch -- carotid body receptors

Question 36

central chemoreceptors are indirectly sensitive to ____ levels in blood based upon ___.

Answer 36

CO2 levels | pH

Question 37

central chemoreceptor hypersensitivity to CO2 levels lasts for hours but declines with ?

Answer 37

renal adjustments to plasma pH kidneys increase blood bicarbonate levels

Question 38

central chemoreceptors are especially sensitive to ?

Answer 38

[H+] H+ does not easily cross blood brain barrier but CO2 does

Question 39

peripheral chemoreceptors are sensitive to ?

Answer 39

concentrations of o2, co2, H+

Question 40

describe type I glomus cells

Answer 40

Chemosensors located close to fenestrated capillaries

Question 41

function of type I glomus cells in high pO2

Answer 41

K+ efflux when pO2 is high | cells are hyperpolarized

Question 42

function of type I glomus cells in low pO2

Answer 42

K channels close cells depolarize Ca channels open NTs released

Question 43

type II Sustentacular cells

Answer 43

play a support role similar to glial cells

Question 44

location and function of slow-adapting pulmonary stretch receptors

Answer 44

w/in airways of the lungs sensitive to stretch of airways important in controlling respiration in infants and adults during exercise

Question 45

signals from slow-adapting pulmonary stretch receptors

Answer 45

signals travel in vagus n to medulla effects: terminate inspiration prolong expiration

Question 46

pulmonary stretch receptors are ?

Answer 46

mechanoreceptors

Question 47

location and function of rapidly-adapting pulmonary stretch receptors

Answer 47

w/in airways of lungs sensitive to irritation, foreign bodies and stretch

Question 48

effects of rapidly-adapting pulmonary stretch receptors

Answer 48

signals travel in vagus n to brain signals elicit cough these receptor signals override normal respiratory control mechanisms

Question 49

J receptors location and function

Answer 49

sensory endings in alveolar wall in juxtaposition to pulmonary capillaries - c fibers sensitive to pulmonary edema

Question 50

J receptors effects

Answer 50

signals travel to brain via vagus n signals elicit coup and tachypnea this reflex can override normal breathing mechanisms

Question 51

describe the Cheyne-Stokes breathing pattern

Answer 51

cycles of hyperpnea and apnea, repeat each cycle is 30s to 2 min long

Question 52

define hyperpnea

Answer 52

increasingly deeper and rapid breathing followed by a gradual decrease

Question 53

define apnea

Answer 53

follows hyperpnea resulting in a temporary stop

Question 54

periodic breathing

Answer 54

Cheyne-stokes breathing is called this when the apnea segment is replaced w/ hypopnea

Question 55

define hypopnea

Answer 55

abnormally small breaths these breaths are too small to ventilate the lungs

Question 56

define central sleep apnea syndrome

Answer 56

when periodic breathing occurs during sleep caused by damage to central respiratory centers abnormalities of respiratory neuromuscular apparatus

Question 57

what conditions lead to Cheyne-Stokes breathing?

Answer 57

a long delay in transport of blood from lungs to brain such occurs during cardiac failure or increased negative feedback that occurs in brain damage