Part VIII

Question 1

Where are peripheral chemoreceptors located?

Answer 1

aortic and carotid bodies

Question 2

How much CO2 induces increase in ventilation?

Answer 2

20-30%

Question 3

Are peripheral chemoreceptors responsive to CO2 or O2?

Answer 3

decreased O2 (hypoxia)

Question 4

The response to hypoxia is blunted if what falls as oxygen levels fall?

Answer 4

CO2

Question 5

Are peripheral chemoreceptors responsive to CO2?

Answer 5

a little, but not the same as a decrease in oxygen

Question 6

Peripheral chemoreceptors are altered by what?

Answer 6

CNS

Question 7

When the SNS decreases flow to the peripheral chemoreceptors, what happens?

Answer 7

There is an increase in sensitivity to hypoxia

Question 8

What do we use the oxygen consumed after exercise?

Answer 8

to replenish oxygen stores and remove lactic acid

Question 9

How much oxygen is stored in the body on a regular basis?

Answer 9

2L

Question 10

Where is the extra oxygen stored?

Answer 10

.2L in lungs, 1L with hemoglobin, .3L muscle myoglobin

Question 11

How fast is the oxygen store used during exercise?

Answer 11

2 minutes

Question 12

How much oxygen debt can the body reach?

Answer 12

11.5L

Question 13

After exercise, ventilation and oxygen uptake remain high until what?

Answer 13

oxygen is replaced

Question 14

What is alactacid oxygen debt?

Answer 14

oxygen debt the first couple minutes post exercise to recondition the phosphagen system

Question 15

What is lactic acid oxygen debt?

Answer 15

oxygen debt that occurs over 40 minutes post exercise to remove the lactic acid

Question 16

What causes extreme fatigue?

Answer 16

lactic acid

Question 17

What decreases as you ascend?

Answer 17

barometric pressure

Question 18

What is normal PO2?

Answer 18

.21

Question 19

At how many feet will blood “boil”?

Answer 19

47mmHg

Question 20

What doesn’t change with altitude?

Answer 20

the concentration of oxygen

Question 21

What do u acclimatized people suffer from?

Answer 21

Deterioration of nervous system function

Question 22

What are the effects of hypoxia?

Answer 22

Sleepiness, false sense of well being, impaired judgement, clumsiness, blunted pain perception, decreased visual acuity, tremors, twitching, seizuers

Question 23

What can occur during acute mountain sickness?

Answer 23

Cerebral edema, pulmonary edema

Question 24

What is cerebral edema?

Answer 24

hypoxia + local vasodilation (systemic dilation)

Question 25

What is pulmonary edema?

Answer 25

hypoxia + local vasoconstriction (lungs constrict to get air to better areas)

Question 26

When exposed to low PO2 at high altitude, when does hypoxic stimulation of arterial peripheral chemorecetors?

Answer 26

immediately

Question 27

Are central chemoreceptors affected by hypoxia?

Answer 27

no, only increase in CO2

Question 28

What happens when you enter the hypoxic situation?

Answer 28

increased ventilation decreases CO2, which limits increase in ventilation as pH increases (respiratory alkalosis)

Question 29

What happens when increased ventilation decreases CO2?

Answer 29

it limits the increase in ventilation as pH increases (respiratory alkalosis)

Question 30

What happens when there is an increase in body pH?

Answer 30

inhibits ventilaiton and opposes the stimulatory effects of hypoxia on peripheral chemoreceptors

Question 31

What happens after being hypoxic because of high altitudes after a couple days?

Answer 31

ventilation increases 5x as inhibition fades because excretion of HCO3 by kidneys

Question 32

What happens when kidneys excrete HCO3?

Answer 32

it offsets decrease in CO2 to push pH back to normal. Now the hypoxic stimulation of chemoreceptors is no longer opposed by alkalosis and ventilation can increase 5 fold

Question 33

What happens during chronic mountain sickness?

Answer 33

increase in red cell mass, increase pulmonary arterial blood pressure, enlarged right ventricle, decreased TPR, congestive heart failure, death if person is not removed to lower altitude

Question 34

Why is an increase in red blood cell mass bad?

Answer 34

thicker blood, less O2 available, increased carrying capacity to better get O2 to tissues

Question 35

What happens when people are acclimatized?

Answer 35

``` great increase in pulmonary ventlation increase in RBCs increase diffusing capacity of lungs increase tissue vascularity increase ability of tissues to use O2 increased synthesis of 2,3DPG ```

Question 36

What does increase synthesis of 2,3 DPG do?

Answer 36

shifts oxy-hemoglobin dissociation curve to right, which is an advantage to the tissues, but not to the lungs

Question 37

Where is there an incrase ability of tissues to use oxygen?

Answer 37

slight increase cell mitochondria | slight increase in cellular oxidative systems

Question 38

What is different about people who have natural acclimization?

Answer 38

high rate of ventilatory capacity compared to body mass increase size of right ventricle shift in oxy-hemoglobin dissociation curve

Question 39

What is hyperbarism?

Answer 39

when pulmonary capillary blood is exposed to extremely high alveolar gas pressures

Question 40

Can the high pressures under the sea be lethal?

Answer 40

yes