Pulmonary Physiology: Regulation of Respiration

Question 1

Activates muscles of breathing via spinal and cranial motor neurons innervating thoracic/abdominal and laryngeal/pharyngeal muscles

Answer 1

Central respiratory controller

Question 2

Feedback from peripheral and central chemoreceptors assess changes in blood and CSF levels of

Answer 2

O2, CO2, and pH

Question 3

Higher brain centers such as those responsible for sleep, wake, exercise, and emotion also regulate

Answer 3

Respiratory drive

Question 4

Terminates inspiration (lung inflation)

Answer 4

Peripheral vagal feedback

Question 5

Located in the rostral third of the pons

-The location of the pneumotaxic center

Answer 5

Pontine respiratory neurons (PRG)

Question 6

Mediates smooth transition from inspiration to expiration by inhibiting inspiratory activity

-Located in PRG

Answer 6

Pneumotaxic center

Question 7

The caudal 2/3 of the pons contains the

Answer 7

Apneustic center

Question 8

In the absence of vagal feedback and the pneumotaxic center inspiratory terminating influences, we see the emergence of an

Answer 8

Apneustic breathing pattern (prolonged inspiration)

Question 9

Contains the neurons responsible for spontaneous rythm generation

Answer 9

Medulla

Question 10

Contains both inspiratory and expiratory neurons

Answer 10

PRG (n. parabrachialis and kolliker-fuse n.)

Question 11

Activation of PRG leads to

Answer 11

Rapid, shallow breathing

Question 12

Contians only inspiratory neurons

Answer 12

DRG (in nucleus tractus solitarius)

Question 13

Contains both inspiratory and expiratory neurons

Answer 13

VRG (n. ambiguous, retrofacial n. and n. retroambigualis)

Question 14

The respiratory “pacemaker” that can initiate rhythm generation

-part of VRG

Answer 14

Pre-Bötzinger complex

Question 15

Respiratory rhythm is generated through a process of reciprocal inhibition between the

Answer 15

Inspiratory and expiratory neurons

Question 16

Peripheral (carotid & aortic bodies) and central (rostroventral medulla) sites that make adjustments in breathing depth and rate based on changes in arterial blood gas tensions and pH

Answer 16

Chemoreceptors

Question 17

Make adjustments in breathing depth and rate based on expansion of the lung and chest as well as irritation of the airways

Answer 17

Mechanoreceptors

Question 18

The carotid body changes its level of activity in response to changes in

Answer 18

PaO2, PaCO2, and pH

Question 19

Carotid body activity increases when PaO2 drops below

Answer 19

60 mmHg

Question 20

Carotid body activity increases when

Answer 20

PCO2 increases (pH decreases)

Question 21

Carotid body activity decreases when

Answer 21

PCO2 decreases (pH increases)

Question 22

The central chemoreceptors change their activity in response to changes in

Answer 22

PCO2 and pH

Question 23

Increases in PaCO2 normally increase

Answer 23

Ventilation

Question 24

Respiratory diseases which severely impair the ability to excrete CO2 (e.g., severe COPD) result in chronic CO2 retention causing a desensitization of this center and these patients rely on their

Answer 24

Hypoxic drive ventilation

Question 25

Ventilation during the awake state is regulated by

Answer 25

Chemical and mechanical drives and arousal

Question 26

During sleep we lose the “wakefullness stimulus” this results in

Answer 26

Hypoventilation

Question 27

During sleep, respiratory drive is controlled

Answer 27

Chemically

Question 28

Can also result with narcotics, COPD, or deep anesthesia

Answer 28

Hypoventilation

Question 29

Hypoventilation can be caused by

Answer 29

Sleep, narcotics, COPD, and deep anesthesia

Question 30

Occurs with metabolic acidosis due to either peripheral or central chemosensory stimulation

Answer 30

Hyperventilation

Question 31

Chemical drive alters ventilation due to a combination of both

Answer 31

CO2 drive and hypoxic drive

Question 32

When PaO2 is 100 mm Hg, ventilation is regulated by the level of PCO2 primarily due to stimulation of

Answer 32

Central chemoreceptors (some contribution from carotid body)

Question 33

When PaO2 levels decline below 60 mmHg, ventilation is regulated by both

Answer 33

PCO2 and PO2

Question 34

Sensed by peripheral (primarily carotid body) chemoreceptors as O2 tension (PaO2) only and not O2 content (CaO2) or saturation (SaO2) (i.e., no response to breathing carbon monoxide)

Answer 34

Hypoxia

Question 35

Hypoxic drive is a result of stimulation of the

Answer 35

Carotid body chemoreceptors

Question 36

Hypoxia alone will have what affect?

Answer 36

Increased ventilation and decreased PCO2

Question 37

Simultaneous increases in PaCO2 potentiates the increase in 𝑉ventilation at any given PaO2 enhancing the

Answer 37

Hypoxic drive

Question 38

H+ does not cross the blood-brain-barrier so metabolic acidosis results in hyperpnea due to stimulation of the

Answer 38

Peripheral chemoreceptors

Question 39

Hyperpnea (Ventilatory compensation) decreases PaCO2 and causes a rise in pH and a reduction in

Answer 39

Peripheral chemoreceptor drive

Question 40

The reduction in arterial blood PCO2 creates a downhill CO2 gradient from the CSF to the arterial blood which results in an increase in CSF pH and a reduction in the

Answer 40

Central chemoreceptor drive

Question 41

The ventilatory response to exercise can be broken down into

Answer 41

Three phases

Question 42

Characterized by an abrupt increase in ventilation, which reflects the anticipatory response

Answer 42

Phase I

Question 43

Gradual increase in ventilation involving a variety of afferents

Answer 43

Phase II

Question 44

Steady state of ventilation that reflects a precise matching of ventilation to metabolism

Answer 44

Phase III

Question 45

During slow wave sleep, we have

Answer 45

Hypoventilation

Question 46

Repetitive episodes of upper airway collapse during sleep, resulting in partial or complete cessation of airflow despite persisting respiratory effort

Answer 46

Obstructive sleep apnea

Question 47

The respiratory control centers are located in the

Answer 47

Medulla and Pons

Question 48

The brain centers responsible for respiratory rhythm generation and patterning (amplitude and frequency) of the integrated neural output consist of the

Answer 48

Pneumotaxic center, apneustic center and the medullary dorsal and ventral respiratory groups

Question 49

There are three major classes of vagal mechanoreceptors. What are they?

Answer 49

Slowly-adapting (stretch receptors), rapidly adapting (irritant receptors), and non-myelinated nerve endings (J receptors)