Respiration Regulation

Question 1

ºRegulator of ventilation?

Answer 1

P_aco₂

Question 2

Central ventilation controllers establish what?

Activate what?

Answer 2

Respiratory rhythm

Respiratory mm (effectors)

Question 3

Feedback Control Loop:

3 parts

Answer 3

CENTRAL CONTROL

(pons, medulla)

↓

output to

EFFECTORS

(respiratory mm)

↓

SENSORS

(chemoreceptors, lung)

↓

input back to brain

Question 4

CENTRAL CONTROLLER: Medulla

3 parts?

Purpose of each?

Answer 4

1) Rostral Ventromedial Neurons (rhythm generation)
2) Dorasl Respiratory Group [DRG] (inspiratory)
3) Ventral Respiratory Group [VRG] (inspiratory and expiratory)

Question 5

CENTRAL CONTROLLER: Pons

2 parts?

Purpose of each?

Answer 5

1) Pneumotaxic Center (turns off inspiration at DRG)
2) Apneustic Center (prolongs inspiration)

Question 6

Medulla Dorsal Respiratory Group (DRG):

Active when?

Answer 6

active during eupnea

Question 7

Medulla DRG:

Receives input from what CNs?

Answer 7

CN IX/X chemorecpetors

CN X mechanoreceptors

Question 8

Medulla DRG:

Innervates diaphragm thru what CN?

Answer 8

CN X

Question 9

Medulla DRG is passive when?

Answer 9

during expiration

Question 10

Medulla Ventral Respiratory Group:

Active when?

Passive when?

Answer 10

Active during forced expiration

Passive during eupnea

Question 11

Pontine (pons) Pneumotaxic Center:

Turns off what?

Which limits what?

Answer 11

inspiration at DRG

limits size of tidal volume

Question 12

Pontine Apneustic Center:

When stimulated causes what?

Answer 12

apneusis:

prolonged inspiration gasp followed by brief expiration

Question 13

Cortical control of respiration is used when?

Answer 13

Need voluntary control for speech, sigh, etc

Question 14

Cortical control of respiration can produce what effect on:

Ventilation?

P_Aco₂?

Answer 14

Double ventilation

Cut P_Aco₂ in half

Question 15

Limbic system affects ventilation how?

Answer 15

causes emotionally-induced ∆s

(e.g. fear)

Question 16

Hypothalamus affects ventilation how?

Answer 16

through temperature control

(e.g. fever)

Question 17

CENTRAL CONTROL sensors are what kind?

Answer 17

chemoreceptors

Question 18

PERIPHERAL CONTROL sensors are what kind?

Answer 18

chemo and mechanoreceptors

Question 19

CENTRAL CONTROL chemo receptors located?

Answer 19

medulla surface

Question 20

CENTRAL CONTROL chemoreceptors stimulated how?

Answer 20

↑ H+ and CSF

H+ doesn’t cross blood-brain barrier,

reaches medulla when CO2 in the blood crosses BBB and reacts w/ H2O to become H+ and HCO3-

Ѧ PaCO2 is the primary effector of vent regulation

Question 21

CENTRAL CONTROL chemoreceptors are NOT stimulated by?

Answer 21

∆s in Po2

Question 22

PERIPHERAL chemoreceptors located where?

Respond primarily to what?

Answer 22

carotid and aortic bodies

∆s in PaO2

can also detect H+ directly, so they respond to metabolic acidosis (unlike central receptors)

Question 23

What level must PaO2 fall to to signal ∆ in ventilation?

Answer 23

60-70 mmHg

Question 24

PO2 levels above 70 mmHg have what effect on the CNS?

Answer 24

Inhibitory

Question 25

Hering-Breuer Reflex is?

Answer 25

reflex of pulmonary mechanoreceptors to stretch:

at large tidal volumes (> 1L), stretch inhibits inspiration

Question 26

Chest wall and proprioreceptors ↑ ventilation how?

Answer 26

limb movement

Question 27

Peripheral Irritant Receptors do what?

Answer 27

bronchoconstrict in response to irritants in air

Question 28

Peripheral J Receptors located where?

Do what?

Answer 28

alveolar walls

stim respiration in response to pulmonary capillary engorgement

(e.g. LHF backs-up pulmonary circ, causes tachypnea)