Lecture 9: Respiratory Control

Question 1

Chemoreceptors look at O2 levels at the _____ side to determine respiration control

Answer 1

arterial

Question 2

What are the 4 medullary respiratory centers?

Answer 2

Dorsal respiratory group
Ventral respiratory group
Pontine respiratory group
Botzinger complex
Pre Botzinger complex

Question 3

DRG is located _____

VRG is located _____

Answer 3

Medially

laterally

Question 4

Brain determines () and () of breathing and sends info to which effectors?

Answer 4

Timing (frequency) and depth (tidal volume/pattern)

Motor neurons that control respiratory muscles

Question 5

What is the significance of the Pre-Botzinger complex?

Answer 5

Controls respiratory timing by turning on inspiration (basically tells you to inspire again, thus controlling breathing frequency)

Question 6

What other area helps control respiratory timing?

What happens when this is lesioned?

Answer 6

PRG

Stuck in inspiration (cannot turn it off) = apneusis

Question 7

What respiratory centers determine breathing pattern/depth aka hard we breath?

Answer 7

DRG

VRG

Question 8

How does the DRG control breathing depth?

Answer 8

Sensory info (asthma attack, need to breathe hard!) > DRG neurons > send signal to phrenic nerve > contract diaphragm harder because we need to breathe more

Question 9

The rostral part of the VRG controls () muscles

The caudal part of the VRG controls () muscles

Answer 9

Inspiratory

Expiratory

Question 10

Apneusis
Characterized by…
Damaged area?

Answer 10

Impaired respiratory rate

PRG

Question 11

Apnea
Characterized by …
Damaged area?

Answer 11

No input to muscles, not breathing

Medulla (spinal damage)

Question 12

Chemoreceptors are sensitive to levels of …

Answer 12

Arterial O2, CO2 and pH levels

Question 13

Under what conditions does chemoreceptor firing rate increase, (tell brain breathing is in trouble)?

Answer 13

High CO2 and H+

Low O2

Question 14

How do chemoreceptor neurons respond to hypoxia?

Answer 14

Chemoreceptor neurons receptive to hypoxia and ignores metabolic demands to prioritize fixing the breathing.

Question 15

How do respiratory neurons respond to hypoxia?

Answer 15

Decreases firing rate. So if you don’t have O2, your respiratory neurons don’t tell the muscles to breathe = makes problem worse

Question 16

Where are central and peripheral chemoreceptors found?

Answer 16

Central: in brain (ventral surface of medulla)
Peripheral: in carotid and aorta

Question 17

For “drive” to breathe, what receptors do we rely on?

For irregular breathing changes, what receptors do we rely on?

Answer 17

Central

Peripheral chemoreceptors

Question 18

How do central chemoreceptors work?

Answer 18

Sensitive to CO2 in the brain. CO2 undergoes the dissociation in the brain to H+ and HCO3-. Receptors basically detect increase in H+ in brain (corresponds to how much CO2 entered the BBB)

Question 19

How do peripheral chemoreceptors work?

Answer 19

Sensitive to decrease in O2 and increase in CO2 and H+ and adjust their firing rate to the medullary respiratory centers

Question 20

What are pulmonary stretch receptors?

Answer 20

Sensitive to tidal volume by detecting stretch. Purpose is to stop pulmonary system from hyperinflating itself

Question 21

What are slowly adapting pulmonary stretch receptors?
Which nerve sends info to brain?
End effect?

Answer 21

Located in airways and sensitive to airway stretch.
Sends their info to the brain via Vagus N.
-Inhibit inspiration, prolong expiration

Question 22

Why are slowly adapting pulmonary stretch receptors strong during infancy and exercise?

Answer 22

Infants: Fetal lungs “used” to being collapsed. More sensitive to stretch.
Exercise: avoid damaging the lungs when breathing hard while exercising

Question 23

What are rapidly adapting pulmonary stretch receptors?
Which nerve sends info to brain?
End effect?

Answer 23

Located in airways and sensitive to irritation and foreign bodies, as well as stretch
Sends info to brain via Vagus N.
Trigger cough to expel offending object out

Question 24

What are J (juxtacapillary receptors)?
Which nerve sends info to brain?
End effect?

Answer 24

Receptors near alveolar capillaries that are sensitive to pulmonary edema (lung stiffness)
Vagus N.
Cough, tachypnea (fast and shallow breathing as a way to cope when stiff lungs can’t expand well)

Question 25

What is the significance of RARs and J Receptors?

Answer 25

Activated during times of distress, so they override normal respiratory controls to prioritize protecting survival

Question 26

How does the cortex contribute to respiratory control?

Answer 26

Cortex ignores the medulla and sends their info directly to the breathing muscles