Lecture 11 2/5/24

Question 1

What are the three major parts of the respiratory control system?

Answer 1

-central controller: pons, medulla, other parts of brain
-effectors: resp. muscles
-sensors: chemoreceptors, lung, etc.

Question 2

What type of control does the brainstem have over respiration?

Answer 2

unconscious control

Question 3

What type of control does the cerebral cortex have over respiration?

Answer 3

voluntary control

Question 4

What are the four primary centers of the brainstem for respiratory control?

Answer 4

-dorsal resp. groups (medulla)
-ventral resp. groups (medulla)
-apneustic center (caudal pons)
-pneumotaxic center (rostral pons)

Question 5

What are the characteristics of the dorsal respiratory group?

Answer 5

-involved in inspiration/inspiratory rate
-helps set basic rhythm of breathing
-output travels to diaphragm via phrenic nerve
-input received form vagal and glossopharyngeal nerves
-inhibited by pneumotaxic center

Question 6

What are the characteristics of the ventral respiratory group?

Answer 6

-mainly involved in expiratory function
-sends inspiratory impulses to laryngeal and pharyngeal muscles, diaphragm, and external intercostals
-sends expiratory impulses to abdominal muscles and internal intercostals
-pre-Bötzinger complex regulates respiratory rhythm

Question 7

What are the characteristics of the apneustic center?

Answer 7

-involved in deep inspiration
-lower pons
-prevents inspiratory neurons from being switched off
-prolongs inspiration
-shortens expiration
-held in check by vagal and pneumotaxic center impulses

Question 8

What are the characteristics of the pneumotaxic center?

Answer 8

-inhibit inspiration
-upper pons
-inhibits impulses to medullary inspiratory neurons
-controls length of inspiration

Question 9

What will a strong pneumotaxic center signal do?

Answer 9

-increase resp. rate
-shorten inspiration and expiration
-lower tidal vol.

Question 10

What will a weak pneumotaxic center signal do?

Answer 10

-prolong inspiration
-increase tidal vol.

Question 11

What are the characteristics of the cerebral cortex?

Answer 11

-voluntary control of respiration
-allows for hyperventilation and hypoventilation

Question 12

What are the characteristics of pulmonary stretch receptors?

Answer 12

-inspiration reflex
-inflation of lungs stops inspiration
-deflation of lungs brings on inspiration
-slowly adapting

Question 13

What are the characteristics of the Hering-Breuer reflex?

Answer 13

-lung stretch sends inhibitory signals through vagus to DRG
-most important during increased tidal vol.
-stops inspiration and increases expiration

Question 14

What happens when a disease decreases compliance and increases elasticity?

Answer 14

-more stretch receptor stimulation
-increased resp. rate

Question 15

What are the characteristics of irritant receptors?

Answer 15

-rapidly adapting
-impulses travel up vagus nerve
-stimulation leads to clearance responses

Question 16

What are the characteristics of peripheral chemoreceptors?

Answer 16

-located at carotid and aortic bodies
-signals travel via vagus nerve to aortic bodies and glossopharyngeal nerve to carotid
-release neurotransmitters in response to hypoxia
-increase heart rate

Question 17

What is detected by peripheral chemoreceptors?

Answer 17

-elevations in CO2 and H+ (low pH)
-lower PaO2

Question 18

Why is CO2 said to act as an acid?

Answer 18

high CO2 will lead to greater production of H+ ions

Question 19

What are the characteristics of central chemoreceptors?

Answer 19

-located in medulla
-surrounded by CSF
-monitor pH and CO2 levels in the CSF
-CO2 is most important
-does not respond to changes in PaO2 directly

Question 20

What is the ventilatory response to increased CO2?

Answer 20

increased breathing to expel CO2