Neural Control of Ventilation

Question 1

Ventilation Neuron Locations (3 locations and another point)

Answer 1

Inspiration: rostral medulla
Expiration: caudal medulla
Pons: stabilizes/coordinates
Inspiratory and expiratory neurons seem to alternate in inhibiting each other as well

Question 2

Active Expiration and Auxiliary Muscle Threshold to Activate

Answer 2

20 L/min

Question 3

Tidal Volume vs. Freq

Answer 3

Tidal Volume increases initially as lung ventilation increases, then a little before 20 L/min frequency increases, then at about 20 L/min TV remains constant and freq only continues increasing

Question 4

Hering-Breueur Reflex

Answer 4

Stretch Rs send signals through inhibitory interneurons via Vagus n. to switch from inspiration/expiration or vice/versa (I think)

Question 5

3 Other Mechanical Sensors

Answer 5

Irritant Rs shallow breathing and constrict airways
Juxta-capillary Rs sense stuff in capillaries and slow/halt breathing then go really fast and shallow and may play a role in dyspnea
Other MechanoRs in joints and muscles activate increased ventilation during physical work

Question 6

Effect of pH on Ventilation

Answer 6

Drop in pH increases ventilation to lower CO2. However, if pH drops due to some other acidic compound, change not as drastic/sustained, suggesting this response to acidity senses CO2 instead of H+ directly

Question 7

Effect of Low O2 on Ventilation

Answer 7

Increases, but not as drastically as if CO2 is also built up.

Question 8

6 Differences b/w Peripheral and Central ChemoRs

Answer 8

Respond to dec O2, inc CO2, and dec pH vs. just CO2 and pH
Monitors arterial blood vs. brain EC space/CSF
Works in seconds vs. minutes
Doesn’t adapt vs. does adapt
Receives blood flow vs. doesn’t
Affected by nicotine (increase) vs. barbituates (decrease)

Question 9

Cheyne-Stokes Breathing

Answer 9

Under mild hypoxia, 5-20s periods of apnea followed by hyperventilation w/ change in TV gets rid of so much CO2 that breathing temporarily halted until CO2 builds up again

Question 10

Biot’s Breathing

Answer 10

After brain damage -> elevated CSF hydrostatic pressure, abrupt changes b/w deep breathing and pause w/ gasping

Question 11

Kussmaul Breathing

Answer 11

Metabolic acidosis (like from diabetes) leads to very deep breaths to balance CO2. Hyperventilation via TV, not freq