Trachte: Respiratory System Under Stress

Question 1

How does exercise affect O2 consumption?

Answer 1

It can INCREASE to 3000-6000 ml/min from a baseline of 250 ml

Question 2

How does exercise affect CO2 consumption?

Answer 2

It can increase to 3000 ml/min from a baseline of 200

Question 3

What can lead to the dramatic increase in O2 and CO2 consumption during exercise?

Answer 3

VENTILATION

Question 4

What happens to the respiratory quotient during exercise?

Answer 4

It can increase to one or higher

Question 5

How can the respiratory quotient be higher than 1?

Answer 5

It is greater than one because the bicarb buffer is making up for acidosis at the VO2 max.

Question 6

What happens to diffusion capacity during exercise?

HOw is this measured?

Answer 6

It increases 3 fold!

CO uptake per partial pressure gradient

Question 7

What happens to cardiac output during exercise?

Answer 7

It increases 3-4 fold

Question 8

Why does CO increase?

Answer 8

There is both increased HR and SV

Question 9

How does increased HR and SV occur? What’s the efferent signal?

Answer 9

Sympathetic activation increases HR

SV- sympathetics> increased Venous return

Question 10

What happens to systolic and diastolic pressure during exercise?

Answer 10

Systolic INCREASES

Diastolic DECREASES or is unchanged

Question 11

What happens to resistance during exercise?

Answer 11

Since CO is dramatically increased, resistance falls during exercise

Question 12

What happens to PO2 during exercise?

Answer 12

Unchanged or rises slightly

Question 13

What happens to PCO2 during exercise?

Answer 13

decreased slightly

Question 14

What happens to pH during exercise? Why?

Answer 14

Decreased

Lactic acid building up

Question 15

What happens to atm pressure with altitude?

Answer 15

It DECLINES

Question 16

How do you calculate inspired PO2?

Answer 16

Inspired PO2= (atm pressure-47) x .2093

47 is vapor pressure of water involved in humidification of inspired air

Question 17

What is the most critical adaptation at high altitude?

Answer 17

HYPERVENTILATION

Question 18

What drives hyperventilation?

Answer 18

Low O2*

Question 19

What is polycythemia?

Answer 19

Besides hyperventilation, it is another critical adaptation at HIGH altitude.

RBC numbers in blood INCREASE in response to hypoxia

Question 20

What does polycythemia do?

Answer 20

Increases the oxygen carrying capacity of blood

Question 21

How does hypoxia lead to an increase in RBCs?

Answer 21

stimulates EPO

Question 22

Shifts in the O2 dissociation curve
INCREASED VASCULARIZATION of tissues
increased oxidative enzymes
pulmonary VASOCONSTRICTION

Are all adaptive responses to….

Answer 22

High altitude

Question 23

What causes acute mountain sickness?

Answer 23

respiratory alkalosis and hypoxia

Question 24

Why can it be bad to breathe 100% oxygen?

Answer 24

It’s damaging to tissues!

It chronically decreases VITAL CAPACITY and can cause PULMONARY EDEMA

Question 25

How does breathing 100% oxygen cause atelectasis (collapse of alveoli)?

Answer 25

It creates an ENORMOUS DIFFUSIONAL GRADIENT for air movement into the blood causing the alveoli to COLLAPSE PO2: 668: 55 PCO2= 45:45 PH20 = 47:47

Question 26

What happens to N at high and low pressures?

Answer 26

High- N equilibrates w/ tissues Low- returned to blood

Question 27

What happens if decompression occurs too quickly?

Answer 27

N escapes from blood as bubbles causing pain and neurological damage if bubbles form in the cranial circulation

Question 28

How do you avoid hte bends?

Answer 28

replace N w/ helium

Question 29

When is hyperbaric oxygen used?

Answer 29

CO poisoning

Question 30

Why is hyperbaric oxygen used to treat CO poisoning?

Answer 30

Can increase O2 content of blood to 6 ml/dL by icnreasing pressure to 3 atm (.003 ml O2/dL/1 mmHg)

Question 31

Describe the pathway for fetal oxygenation?

Answer 31

Umbilical a. picks up oxygen from placenta> returns it to RA> Most goes through the FORAMEN OVALE and oxygenates tissues

Question 32

What is the PO2 of aortic blood in the fetus?

Answer 32

22-30 mmHg

Question 33

What happens to most of the blood being pumped to the lung in fetal circulation?

Answer 33

Goes through the DA to get to systemic circulation

Question 34

Why is the first breath of the fetus so important?

Answer 34

It requires ENORMOUS PRESSURE to overcome surface tension and lungs partially filled w/ fluid> ENORMOUS drop in PULMONARY RESISTANCE

Question 35

What causes hte drop in pulmonary resistance?

Answer 35

oxygenation of alveoli

Question 36

What closes the foramen ovale at birth?

Answer 36

Increased pressure in the left atrium

Question 37

What physiological variables does exercise increase?

Answer 37

``` O2 consumed CO2 produced H ion produced HR SV CO AV oxygen content Alveolar ventilation Systolic BP ```

Question 38

What physiological variables does high altitude increase and decrease?

Answer 38

Increases ventilation and hematocrit (EPO) Decreases PCO2 and PO2 **hypoxia is driving force

Question 39

Why can pure O2 be harmful?

Answer 39

It can cause atelectasis

Question 40

How does diving lead to the bends?

Answer 40

Diving causes compression or expansion of gas containing organs and can lead to the bends if N escapes from the blood to fast

Question 41

How do you treat CO poisoning?

Answer 41

Hyperbaric oxygen

Question 42

What is the state of oxygen tension and pulmonary artery resistance in the fetus?

Answer 42

Oxygen tension is LOW Pulmonary artery resistance HIGH