Control of Ventilation

Question 1

Where is the “central controller” for ventilation?

Answer 1

brainsteam = pons and medulla (although the cortex can override the brainstem to icnrease or decrease breathing)

Question 2

The effector mechanisms on ventilation are mainly through what?

Answer 2

control of the respiratory muscles: diaphragm, itercostals, abdominal muscles and sternocleidomastoids

Question 3

What is the most important sensor in day-to-day regulation of ventilation?

Answer 3

the central chemoreceptors

Question 4

what do the central chemoreceptors respond to?

Answer 4

pH (baseically, the more CO2 that diffuses across the BBB, the more acidic the area will be - lower pH)

Question 5

Where are the peripheral chemoreceptors located?

Answer 5

aortic arch and carotid bodies

Question 6

What do the periephral chemoreceptors respond to?

Answer 6

pCO2, pH and pO2

Question 7

WHat are the 4 lung receptors?

Answer 7

stretch receptors
irritant receptors
J receptors (sense fluid in the lungs)
Bronchial C fibers (trigger pain)

Question 8

What type of response will the central chemoreceptors trigger when there’s icnreased H+ and lower pH?

Answer 8

will increase responration

Question 9

What type of response will occur in alkalosis then?

Answer 9

hypoventilation

Question 10

Why do we say the CO2 is more important for the central chemoreceptors if they’re actually sensing H+ and pH?

Answer 10

Because H+ can’t cross the BBB but CO2 can.

it’s the CO2 that diffuses across and then pushes the buffer reaction toward H and HCO3

Question 11

What is normal CSF pH?

Answer 11

7.32

Question 12

An aberrant CSF acidosis is eventually compensated for how?

Answer 12

by HCO3 retention

Question 13

Which are particularly important for detecting hypoxia: aortic arch receptors or carotid bodies?

Answer 13

carotid bodies

Question 14

Which ones: aortic or carotid - respond to a decrease in pH?

Answer 14

carotid

Question 15

What will both carotid and aortic respond to?

Answer 15

hypercapcnia (but this isn’t as important as the central chemoreceptor response to hypercapnia)

Question 16

What is the Herring-Breuer reflex?

Answer 16

the pulmonary stretch receptors will suppress further inspiration if the lungs are stretch too far

it’s relevant in yoga because it slows breathing and heart rate

Question 17

What will the irritant receptors trigger in response to cigarette smoke na dother noxious gases?

Answer 17

bronchoconstriction and hyperpnea - to protect the lungs

Question 18

What do the juxtacapillary receptors respond to? WHat’s the response?

Answer 18

respond to engorgement of capillaries and increased interstitial pressure - fluid in the lungs

they may mediate shallow breathing and tachypnea associated with heart failure

Question 19

What will the bronchial C fibers trigger in response to noxious chemicals in bronchial circulation?

Answer 19

bronchoconstriction, mucous secretion and rapid shallow breathing

Question 20

What do joint and muscle receptors do to respiratory rate?

Answer 20

movement of limbs increases respiratory rate - believed to be the stimulus for increased breathing in exercise

Question 21

Response to carbon dioxide: each 1 mmHg increase in Pco2 tends to cause a _____ increase in ventilation if pO2 is help constant.

Answer 21

2-3 L

Question 22

If CO2 is held constant, most individuals won’t respond to hypoxia until the pO2 drops below what?

Answer 22

50 mmHg

Question 23

What are the exceptions to that?

Answer 23

ascent to high altitude

chronic obstructive lung disease that has adapted to changes in pH caused by CO2 retention

Question 24

Again, what’s the ventilation response to acidosis?

Answer 24

hyperventilation

Question 25

WHat happens to pCO2 and pO2 during exercise?

Answer 25

pCO2 decreases and pO2 increases (you breath hard don’t you?)

Question 26

What causes us to breath hard during exercise?

Answer 26

maybe receptors in the joints and muscles
maybe increased load of CO2 to the lungs

not pH because it stays stable until very intense levels of exercise