PSIO202 Exam 2 Lecture 14

Question 1

Even though respiratory muscles are skeletal muscles, they are under both —— and —— control.

Answer 1

automatic and voluntary

Question 2

Where is the automatic control of respiratory muscles controlled from?

Answer 2

inspiratory and expiratory neurons in the medulla of the brainstem

Question 3

Where is the voluntary control of respiratory muscles controlled from?

Answer 3

regions of the cortex

Question 4

Resting breathing is ——–.

Answer 4

rhythmic

Question 5

How is the rhythm of breathing controlled?

Answer 5

by pacemaker like neurons in the medulla

Question 6

What activates inspiratory motorneurons? What does their activation cause?

Answer 6

pacemaker neurons, inspiratory motorneurons synapse onto respiratory muscles

Question 7

What activates expiratory motorneurons?

Answer 7

respiration increases (with exertion or to perform a respiratory task)

Question 8

Where are the neurons that control inspiratory muscles?

Answer 8

dorsal respiratory group (DRG)

Question 9

Where are the neurons that control expiratory muscles?

Answer 9

ventral respiratory group (VRG)

Question 10

Neurons in the DRG and VRG are…

Answer 10

pre-motor neurons

Question 11

What do premotor neurons synapse onto? What is eventually innervated?

Answer 11

synapse onto motoneurons that innervate respiratory muscles

Question 12

What are the three kinds of specialized receptors?

Answer 12

pulmonary stretch receptors, central chemoreceptors, and peripheral chemoreceptors

Question 13

Where are pulmonary stretch receptors located?

Answer 13

smooth muscle lining the large airways, bronchi, and bronchioles

Question 14

How do the pulmonary stretch receptors get their info up to the brainstem?

Answer 14

when the lungs inflate, the receptors are stretched, they respond to the rate of change of lung stretch on the afferent pathway via Vagus nerve (CN X)

Question 15

Where are the peripheral chemoreceptors located?

Answer 15

aortic bodies in the aortic arch, and carotid bodies in the carotid sinus

Question 16

What do peripheral chemoreceptors respond to?

Answer 16

primarily low oxygen in the arterial blood

little bit of response to H+ concentration and CO2

Question 17

How is information from the peripheral chemoreceptors carried back to the control center? What is the control center for these receptors?

Answer 17

info from aortic bodies carried by CNX - vagus
info from carotid bodies carried by CNIX - glossopharyngeal

carried to the medulla

Question 18

Where are the central chemoreceptors located?

Answer 18

adjacent to the respiratory control centers in the medulla

Question 19

What are the principle roles of the central chemoreceptors?

Answer 19

CO2 sensitive by responding to increase in H+ in the CSF

Question 20

How do central chemoreceptors work? Where do the H+ come from?

Answer 20

CO2 in the blood crosses the BBB, enters the CSF and combines with water to form carbonic acid, which breaks down into bicarbonate and H+. Those H+ ions are sensed and indicate an increase in CO2. The central chemoreceptors sense the H+.

Question 21

Are the central or peripheral chemoreceptors faster?

Answer 21

peripheral (they don’t have to wait for crossing the BBB and an entire reaction to take place first)

Question 22

How does information get from central chemoreceptors to the medulla?

Answer 22

They are right next to it, so it is basically already there.

Question 23

What is the general pathway from low O2/high CO2 all the way to increasing ventilation?

Answer 23

change in O2 or H+ activates peripheral or central chemoreceptors, info is carried to the medulla/is already there for central receptors, medulla processes in DSG and VSG and send signals out on inspiratory (DSG) and expiratory (VSG) motoneurons, which innervate the respiratory muscles