Unit 1: Respiratory

Question 1

Neural control of ventilation (rate and pattern)

Answer 1

1. Nueral control in respiratory center (medulla), 2. Chemical control in central chemoreceptors (medulla), 3. Chemical control in peripheral chemoreceptors (carotid bodies and aortic arch), 4. Baroreceptors (lungs)

Question 2

Afferent input to respiratory center

Answer 2

Central and peripheral chemoreceptors (CN 9 and 10), stretch receptors in lungs (CN 10)

Question 3

Control center of respiration

Answer 3

Respiratory center (RAS in medulla and pons)

Question 4

Efferent pathways of respiration

Answer 4

Motor neurons to respiratory muscles (diaphragm, intercostals, accessory muscles)

Question 5

Respiratory Center (4 components)

Answer 5

Pneumotaxic center: Inhibits DRG
Apneustic center: Stimulates DRG
Dorsal respiratory group: Causes inspiration (respiratory pacemaker)
Ventral respiratory group: Causes expiration

Question 6

Pneumotaxic Center

Answer 6

Inhibits DRG
Location: upper pons
Function: triggers the end of inspiration by inhibiting the DRG
Strong stimulus - rapid shallow breathing
Weak stimulus - slow and deep breathing

Question 7

Apneustic Center

Answer 7

Stimulates DRG
Location: lower pons
Function: antagonizes the pneumotaxic center which causes inspiration
Action is inhibited by pulmonary stretch receptors (J receptors)

Question 8

Dorsal Respiratory Group

Answer 8

Causes inspiration (respiratory pacemaker)
Location: medulla (nucleus tractus solitarius)
Function: pacemaker for inspiration (classic teaching); primarily active during inspiration

Question 9

Ventral Respiratory Group

Answer 9

Causes expiration
Location: medulla (nucleus ambiguous, nucleus retroambiguous)
Function: has inspiration and expiration functions (primarily active during expiration); contains the pre-Botzinger complex

Question 10

Respiratory pacemaker function (newer teaching)

Answer 10

Performed by the central pattern generator, which includes the DRG, pre-Botzinger complex (in the VRG), and other medullary structures

Question 11

Central chemoreceptors

Answer 11

Located below the surface of the anterolateral aspect of the medulla; respond to PaCO2 indirectly, send stimulatory impulses to the dorsal respiratory center

Question 12

Most important stimulus for central chemoreceptor

Answer 12

Hydrogen ion concentration in the CSF

Question 13

____ drives the respiratory pacemaker in the dorsal respiratory center

Answer 13

H+

Acute rise in PaCO2 –> increased H+ in CSF and increases minute ventilation
Acute decline in PaCO2 –> decreased H+ in CSF and decreases minute ventilation