Lecture 4- Control of Respiration

Question 1

inspiration requires …. in motor neurons

Answer 1

action potentials

Question 2

expiration due to … of motor neuron activity and lung …

Answer 2

cessation

recoil

Question 3

rhythmic contraction is controlled by … neurons

Answer 3

pacemaker

Question 4

activity of pacemaker neurons can be modulated by activity of …

Answer 4

pulmonary stretch receptors

Question 5

The Hering–Breuer inflation reflex is a reflex triggered to prevent … of the lung. Pulmonary stretch receptors present in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations.

Answer 5

over-inflation

Question 6

activity of pacemaker neurons can also be modulated by ….. which have inhibitory effects and can result in death

Answer 6

drugs (barbituates and opiates/morphine)

Question 7

3 things that can affect the activity of pacemaker neurons

Answer 7

pulmonary stretch receptors

drugs

partial pressures of respiratory gases and [H+]

Question 8

if there is a decrease in PO2 then what happens to ventilation rate

Answer 8

increase

Question 9

if there is an increase in PCO2 or [H+] then what happens to the ventilation rate?

Answer 9

increase

Question 10

the regulation of ventilation rate by respiratory gases and [H+] involves … in two locations

Answer 10

chemoreceptors

Question 11

peripheral chemoreceptors (aortic and carotid bodies) are stimulated by … [H+} or … PO2

Answer 11

increased [H+}

decreased PO2

Question 12

central chemoreceptors are stimulated by …. [H+] in extracellular fluid in brain

Answer 12

increased

Question 13

T/F chemoreceptors can detect dissolved oxygen as well as oxygen bound to hgb

Answer 13

false. can only detect dissolved O2

Question 14

ventilation rate increases below a PO2 of about … mmHg

Answer 14

60 (hgb is still 90% saturated, so vent rate responds well before blood is close to depleted)

Question 15

is ventilation rate more sensitive to PO2 or PCO2?

Answer 15

PCO2

Question 16

ventilation rate increases with a PCO2 above … mmHg

Answer 16

40

Question 17

which is the primary regulator? central or peripheral chemoreceptors?

Answer 17

central

Question 18

ventilation rate can be modified by non-respiratory sources of H+ such as … and …

Answer 18

metabolic acidosis

metabolic alkalosis

Question 19

metabolic acidosis can be caused by…

Answer 19

excess lactic acid (exercising)

diabetes (ketones)

Question 20

metabolic alkalosis can be caused by …

Answer 20

severe vomiting

Question 21

T/F anemia and carbon monoxide poisoning do not change ventilation rate

Answer 21

true

Question 22

why do anemia and carbon monoxide posioning not affect ventilation?

Answer 22

because the dissolved PO2 is the same but these conditions affect PO2 that is bound to hgb. so total PO2 is reduced but not the dissolved PO2

Question 23

why is increased PCO2 from exercise not the explanation for increase in ventilation during exercise?

Answer 23

increased PCO2 is in the venou blood (no receptors there)

in fact PCO2 can be decreased because of hyperventilation due to ventilation matching CO2 production or better

Question 24

why is decreased PO2 not the explanation for ventilation change during exercise?

Answer 24

decreased PO2 is in the venous blood

Question 25

why is increased [H+] not the explanation for increase in ventilation during exercise?

Answer 25

only during strenuous exercise

Question 26

what are other factors that have input to the respiratory center during exercise?

Answer 26

temperature conditioned response epi and K+ proprioceptors(joints)

Question 27

what is the most likely reason for increase in ventilation during exercise?

Answer 27

motor cortex that sends signals to muscles is also sending signals to the resp. center

Question 28

... is a deficiency of O2 at the tissue level

Answer 28

hypoxia

Question 29

... hypoxia happens with decreased arterial PO2

Answer 29

hypoxic (hypoxemia)

Question 30

... hypoxia is when there is normal arterial PO2 but decreased hgb O2 and decreased overall O2 content of the vlood

Answer 30

anemic

Question 31

... hypoxia is when blood flow to the tissues is too low

Answer 31

ischemic

Question 32

... hypoxia is when the cell are unable to utilize O2

Answer 32

histotoxic | example cyanide poisoning

Question 33

conditions that cause hypoxemia (4)

Answer 33

hypoventilation diffusion impairment vascular shunt vent-perf inequality

Question 34

2 immediate responses to high altitude

Answer 34

stimulate ventilation increased dependence on anaerobic glycolysis

Question 35

what are 3 delayed responses to high altitude (acclimatization)

Answer 35

increased erythropoesis--> polycythemia (stim by EPO from the kidney) increased 2,3-DPG synthesis (shift curve to right) increased synthesis of other components of O2 delivery (capillary density, myoglobin, mitochondria)

Question 36

you can train at high altitude to stimulate ... production in response to low arterial PO2

Answer 36

EPO

Question 37

old school gene doping

Answer 37

RBC packing or use recombinant human EPO

Question 38

modern gene doping

Answer 38

use gene therapy to increase endogenous EPO

Question 39

dangerous side effects blood doping

Answer 39

increased blood viscosity increased risk of stroke high BP autoimmune anemia