Respiratory Control

Question 1

What does the pre-Botzinger complex control? Where is it located?

Answer 1

The timing (frequency) of the respiratory rhythm. It is a central pattern generator. In the medulla.

Question 2

What is apneusis?

Answer 2

Failure to turn respiration off (stuck in inspiration)

Question 3

What happens when the PRG is lesioned?

Answer 3

Apneusis. Lose the ability to turn inspiration off without additional info from the vagus nerve.

Question 4

What are the four medullary respiratory centers?

Answer 4

1. ) DRG
2. ) VRG
3. ) PRG
4. ) Botzinger complex

Question 5

What two things control the length of inspiration under normal circumstances?

Answer 5

1. ) Pre-botzinger complex

2. ) PRG

Question 6

What is the function of the DRG?

Answer 6

It receives a lot of sensory information which it then relays to the phrenic nerve. The sensory information allows it to generate a pattern appropriate to the circumstances.

It controls depth of breathing

Question 7

What are the two portions of the VRG? Where are they located?

Answer 7

The dorsal and caudal portions. Each have different functions to control inspiration and expiration. Located in the medulla.

Question 8

What is the function of the rostral portion of the VRG?

Answer 8

Premotor to phrenic and other inspiratory muscles

Question 9

What is the function of the caudal portion of the VRG?

Answer 9

Premotor to the upper airway and muscles of expiration

Question 10

What two things determine the depth of a breath?

Answer 10

1. ) DRG

2. ) VRG

Question 11

What is the function of the PRG? Where is it located?

Answer 11

Modifies inspiratory timing and shuts off inspiration. If it malfunctions it leads to apneusis. It is located in the pons.

Question 12

What is the appearance of apneusis, what does it result from, and what are the effects?

Answer 12

Appearance: maintained inspiration

Results from: damage to the pons

Effects: Increased CO2, decreased O2, and death if not supported

Question 13

What is the appearance of apnea, what does it result from, and what are the effects?

Answer 13

Appearance: failure of inspiration (no effort)

Results from: medulla or spinal cord damage

Effects: Increased CO2, decreased O2, and death if not supported.

Question 14

What is a chemoreceptor?

Answer 14

A neuron that is sensitive to a specific chemical. In the respiratory system, these chemicals are CO2, O2, and hydrogen.

Question 15

What changes in chemical concentrations will increase the firing rate of a chemoreceptor? (3 things)

Answer 15

1. ) Increase CO2
2. ) Decrease O2
3. ) Increase H+

Question 16

How do chemoreceptors work?

Answer 16

They notice either a decrease or increase in a chemical concentration in the blood and then activate the respiratory centers.

Question 17

Function of chemoreceptors during hypoxia or hypercapnia?

Answer 17

They notice and increased amount of CO2, decreased amount of O2, or increased H+. They then active the respiratory centers and increase respiration.

Question 18

What are the two sets of chemoreceptors? Where are each located?

Answer 18

1. ) Central - in the ventral surface of the brainstem (medulla)
2. ) Peripheral - in the carotid artery (carotid body) and the aorta (aortic arch)

Each has a different role.

Question 19

How do central chemoreceptors work?

Answer 19

They are indirectly sensitive to CO2 and directly sensitive to CSF pH. They are not sensitive to O2 or H+ concentration in the blood.

CO2 crosses the BBB, reacts with water in the CSF, goes through bicarb process, and the H+ produced stimulates the chemoreceptors.

Question 20

What neurotransmitter has an affect on carotid peripheral chemoreceptors?

Answer 20

Dopamine

Question 21

What are the peripheral chemoreceptors directly sensitive to?

Answer 21

O2, CO2, and H+

Question 22

What are the influence and effects of central chemoreceptors?

Answer 22

Influence: “respiratory drive” or drive to breath

Effects: Increased respiratory rate and depth in response to hypercapnia.

Question 23

What are the influence and effects of peripheral chemoreceptors?

Answer 23

Influence: Acute changes in blood gas

Effects: Increased respiratory rate and depth in response to hypercapnia, hypoxia, or acidosis.

Question 24

Pulmonary stretch receptors are also known as what? (2 types)

Answer 24

slowly adapting pulmonary stretch receptors

or

rapidly adapting pulmonary stretch receptors

Question 25

Where are slowly adapting pulmonary stretch receptors located? What are they sensitive to? What is their effect?

Answer 25

Location: airways

Sensitive to: Stretch of airways (directly proportional to lung volume)

Effect: inhibition of inspiration and prolongation of expiration

Question 26

When are slowly adapting pulmonary stretch receptors important? (2 populations of people)

Answer 26

1. ) Infants

2. ) Adults during exercise

Question 27

Where are rapidly adapting pulmonary stretch receptors located? What are they sensitive to? What is their effect?

Answer 27

Location: Airways

Sensitive to: Irritation, foreign bodies in airway

Effect: Cough

Question 28

Where are J (juxtacapillary) receptors located? What are they sensitive to? What is their effect?

Answer 28

Location: near blood vessels of alveoli

Sensitive to: Pulmonary edema

Effect: Cough, tachypnea

Question 29

Can the cortex influence breathing?

Answer 29

Yes, it acts as a failsafe. It can override the function of the respiratory centers.