Chapter 41 - Guyton

Question 1

Respiratory center in the medulla (3 groups).

Answer 1

dorsal respiratory group - inspiration
ventral respiratory group - expiration
pneumotaxic center - located dorsally in the superior portion of the pons, which mainly controls rate and depth of breathing

Question 2

Important nucleus associated with the dorsal respiratory group.

Answer 2

solitary nucleus (CN IX and X)

Question 3

Increased signal from the pneumotaxic center causes what?

Answer 3

decreased depth and increased rate of breathing

Question 4

Nucleus associated with the pneumotaxic center.

Answer 4

nucleus parabrachialis

Question 5

Nuclei associated with the ventral respiratory group.

Answer 5

nucleus ambiguus (rostrally) and nucleus retroambiguus (caudally)

Question 6

Main function of the ventral respiratory group.

Answer 6

function to increase forceful inspiration and expiration with increased pulmonary ventilation such as with heavy exercise (does not function during normal, quiet breathing)

Question 7

Hering-Breuer inflation reflex

Answer 7

stretch receptors located in the walls of the bronchi and bronchioles of the lungs transmit signals through the vagi into the dorsal respiratory group of neurons when the lungs become overstretched (switch off inspiration)

Question 8

The chemoreceptive area of the respiratory center responds to changes in?

Answer 8

blood carbon dioxide or hydrogen concentration

Question 9

Chemoreceptors (respond to blood oxygen changes)

Answer 9

carotid bodies and aortic bodies

Question 10

Their afferent nerve fibers pass through Hering’s nerves to the glossopharyngeal nerves and then to the dorsal respiratory area of the medulla.

Answer 10

carotid bodies

Question 11

Their afferent nerve fibers pass through the vagi, also to the dorsal medullary respiratory area.

Answer 11

aortic bodies

Question 12

Which is stimulated more rapidly, peripheral chemoreceptors or central stimulation?

Answer 12

peripheral chemoreceptors (however, central stimulation is more powerful; peripheral may play a key role in increase of CO2 at onset of exercise)

Question 13

What occurs during acclimatization?

Answer 13

sensitivity to CO2 decreases and low oxygen is able to stimulate increased alveolar ventilation

Question 14

Why does increased breathing rate occur almost simultaneous to the start of exercise?

Answer 14

collateral impulses excite the respiratory center from the vasomotor center of the brain stem

Question 15

What is the difference between obstructive and central sleep apnea?

Answer 15

obstructive - overweight, fat may be compressing the pharynx, enlarged tonsils, nasal obstruction
central - central nervous system drive to the ventilatory muscles transiently ceases