Neural Control of Breathing

Question 1

What does apneustic mean?

Answer 1

Abnormal respiration marked by sustained inspiratory effort, gasping type of inspiration, breath hold.

Question 2

What does pneumotaxic mean?

Answer 2

Concerning the regulation of breathing, regulates inspiratory time and respiratory rate.

Question 3

What is a chemoreceptor?

Answer 3

A sense organ or sensory nerve ending that is stimulated by and reacts to certain chemical stimuli and that are located outside the central nervous system.

Question 4

Where can chemoreceptors be found?

Answer 4

Large arteries of thorax and neck (carotid and aortic bodies), the taste buds, and the olfactory cells of the nose.

Question 5

What is a proprioceptor?

Answer 5

A receptor that responds to stimuli that originate within the body itself, especially one that responds to pressure, position, or stretch.

Question 6

What is a baroreceptor?

Answer 6

A sensory nerve ending that is stimulated by changes in pressure.

Question 7

Where can you find baroreceptors?

Answer 7

The walls of the atria, vena cava, aortic arch, and carotid sinus.

Question 8

What are the respiratory centers of the brain?

Answer 8

The pons and the medulla oblongata.

Question 9

What does the dorsal respiratory group do?

Answer 9

Provides main inspiratory motor stimulus to diaphragm and intercostals.

Question 10

What does the ventral respiratory group do?

Answer 10

Simultaneously provide inspiratory stimulus to laryngeal and pharyngeal muscles through vagus nerve to increase patency; also abducts vocal cords.

Question 11

How does the dorsal respiratory group work?

Answer 11

It receives input from chemo, proprio, and stretch receptors as well as higher brain centers and then evaluates and prioritizes the impulses in the dorsal respiratory group, then integrates most sensory information to help regulate rate and tidal volume in coordination with the pons, which in turn regulates the pre-botzinger complex in the ventral respiratory group.

Question 12

How does the ventral respiratory group work?

Answer 12

Contains inspiratory and expiratory neurons. Inspiratory: upper airway innervation is mediated by VRG which stimulates and opens these airways via abduction and decreased resistance to airflow occurs; also stimulates diaphragm and external intercostals stimulated during exercise. Expiratory: internal intercostals and abdominal muscles during times of heavy stress or exercise; the firing of expiratory neurons inhibits firing of inspiratory neurons so it is mostly off during quiet breathing.

Question 13

What does the Pneumotaxic Center do?

Answer 13

Receives neural impulses via the vagus nerve from the lung inflation reflex (hering-breuer) and intercostal stretch receptors and sends inhibitory impulses to the medulla that effectively shorten the inspiratory time. Smooths transition from inspiration to expiration.

Question 14

What do strong signals from the PC cause?

Answer 14

Decrease in Ti and increase in RR.

Question 15

What do weak signals from the PC cause?

Answer 15

Increase in Ti and decrease in RR.

Question 16

What is the major function of the Pneumotaxic center?

Answer 16

To limit the inspiratory phase and therefore RR and Vt, suppresses the apneustic center, and fine-tunes the rhythmicity of breathing.

Question 17

What are the central chemoreceptors responsible for?

Answer 17

Monitoring the concentration of H+ in the CSF.

Question 18

What is the blood brain barrier?

Answer 18

A barrier between the bloodstream and the brain which is extremely selective in what it lets through, but is permeable to gases.

Question 19

What are peripheral chemoreceptors responsible for?

Answer 19

They are sensitive to oxygen and react to decreasing PaO2 and are therefore in intimate contact with arterial blood. They are also known as carotid and aortic bodies.

Question 20

Where do peripheral chemoreceptors send their signals?

Answer 20

To the medulla which responds by sending inspiratory signals to the muscles of inspiration; the carotid bodies play a much greater role than the aortic bodies.

Question 21

At what PaO2 are peripheral chemoreceptors activated?

Answer 21

<60mmHG; the further the value falls, the greater the stimulation to breath becomes until PaO2<30mmHg at which point these receptors become supressed.

Question 22

Who would have a chronically elevated PCO2?

Answer 22

People with COPD.

Question 23

When would peripheral chemoreceptors play an increased role in the control of ventilation?

Answer 23

When there is a chronically elevated PCO2 due to chronic lung disease process.

Question 24

What is the target SPO2 for someone with COPD?

Answer 24

88-92%

Question 25

What is the major response of peripheral chemoreceptor stimulation?

Answer 25

An increase in cardiac output.

Question 26

What is the Hering-Breuer response?

Answer 26

When lung stretch receptors “shut off” inspiration at the medulla.

Question 27

What are slow adapting stretch receptors?

Answer 27

They are receptors located in the smooth muscle and are activated by lung stretch or bronchoconstriction and increase exhalation time.

Question 28

What are rapid adapting stretch receptors?

Answer 28

Receptors located between the epithelial cells which primarily respond to irritants to increase ventilation but triggers bronchoconstriciton.

Question 29

What is the deflation reflex?

Answer 29

The absence of stretch, causing an increased respiratory rate.

Question 30

What are juxtapulmonary capillary receptors?

Answer 30

Respond to fluid around the alveoli causing the RR to become rapid and shallow.

Question 31

What is the peripheral proprioception reflex?

Answer 31

Pain and joint activity both cause increased respiratory rate.

Question 32

What is the diving reflex?

Answer 32

When cold water hits the face can produce apnea and bradycardia.