Respiratory Control

Question 1

In what area of the brain is the Pre-Botzinger Complex and what does it do?

Answer 1

• medulla

- generates “core” rhythm

Question 2

In what area of the brain is the Pontine Respiratory Group and what does it do?

Answer 2

• pons
• modifies inspiratory timing (“turns off” inspiration)
• -when lesioned … “stuck in inspiration” (apneusis)

Question 3

In what area of the brain is the Dorsal Respiratory Group?

Answer 3

• medulla, slightly off midline (near dorsal motor nucleus of vagus and hypoglossal nucleus)
• corresponds to the caudal end of the nucleus tractus solitarius

Question 4

For what part of breathing is the Dorsal Respiratory Group responsible?

Answer 4

• depth of breathing
• tidal volume

-95 percent premotor to phrenic N.

Question 5

Where is the Ventral Respiratory Group?

Answer 5

• medulla

- corresponds roughly to nucleus ambiguus

Question 6

For what part of breathing is the Ventral Respiratory Group responsible?

Answer 6

-inspiration, exhalation, and depth

• premotor to phrenic N. and other inspiratory mm.
• premotor to upper airway and expiratory mm.

Question 7

What is the visible appearance of apneusis versus the appearance of apnea?

Answer 7

apneusis: maintained inspiratory discharge
apnea: absence of respiratory effort

Question 8

What area of the brain, if damaged, is responsible for apneusis versus the area responsible for apnea?

Answer 8

• apneusis: pontine damage

- apnea: medullary or spinal cord damage

Question 9

What are the effects of apneusis versus the effects of apnea?

Answer 9

• increased carbon dioxide
• decreased oxygen
• death, if not supported

-in apneusis, this happens after a slight delay

Question 10

What is chemosensitivity?

Answer 10

• the ability of certain chemicals to change the discharge rate of sensitive neurons
• in the respiratory system, the major chemicals are oxygen, carbon dioxide and hydrogen ion

Question 11

What are characteristics of central chemoreceptors?

Answer 11

-directly sensitive to pH of CSF
(indirectly to carbon dioxide in plasma)
-influences the drive to breathe
-increases RR in response to hypercapnia

Question 12

What are characteristics of peripheral chemoreceptors?

Answer 12

• directly sensitive to oxygen, carbon dioxide and H+
• influences acute change in blood gases

-increases RR in response to hypercapnia, hypoxia, or acidosis

Question 13

Where are the central chemoreceptors located?

Answer 13

-on the ventral surface of the brainstem

Question 14

Where are the peripheral chemoreceptors located?

Answer 14

• aortic arch

- carotid body

Question 15

Which reactions are faster, those of the central chemoreceptors or those of the peripheral chemoreceptors?

Answer 15

peripheral

Question 16

What are the characteristics of the Slowly Adapting Pulmonary Stretch Receptors?

Answer 16

• located in the airways
• stimulated by stretch of the lung
• inhibits inspiration and promotes exhalation
• in infants, it plays a role in every breath
• -in adults, only during increased tidal volume

Question 17

What are the characteristics of Rapidly Adapting Pulmonary Stretch Receptors?

Answer 17

• located in the airways
• stimulated by irritants, stretch, foreign bodies
• causes a cough to clear airways
• protective role: not active every breath

Question 18

What are the characteristics of Juxtacapillary (J) receptors?

Answer 18

• located near capillaries in the alveoli
• stimulated by pulmonary edema
• causes a cough and tachypnea
• protects gas exchange surfaces
• -not active every breath

Question 19

What are the characteristics of cortical influences on breathing?

Answer 19

• controls breathing while talking, holding breath, etc.
• cortex appears to bypass the medullary ctrs completely and sends input directly to phrenic N. and muscles of respiration