Respiratory Changes Pt. 2

Question 1

The body contains how much stored oxygen that can be used for aerobic metabolism?

Answer 1

About 2L

Question 2

Where is the body’s stored oxygen located that can be used for aerobic metabolism?

Answer 2

Lungs (.5L)
Body fluids (.25L)
Combined with hemoglobin (1L)
Muscle myoglobin (.3L)

Question 3

In heavy exercise, how quickly is stored oxygen depleted?

Answer 3

Within 2 minutes

Question 4

How much oxygen debt can result from heavy exercise?

Answer 4

11.5L

Question 5

Before oxygen debt is repaired, what two things remain at high levels?

Answer 5

Ventilation and O2 uptake

Question 6

What type of oxygen debt occurs during the first couple of minutes post exercise?

Answer 6

Alactacid oxygen debt (3.5L)

Question 7

What type of oxygen debt occurs over 40 minutes post exercise?

Answer 7

Lactic acid oxygen debt (8.0L)

Question 8

What is associated with alactacid oxygen debt?

Answer 8

Reconditioning of the phosphagen system and replenishing of oxygen stores

Question 9

What is associated with lactic acid oxygen debt?

Answer 9

Removal of lactic acid

Question 10

What is a side effect of lactic acid buildup?

Answer 10

Extreme fatigue

Question 11

What stimulates the first breath at birth?

Answer 11

Cooling of skin and slightly asphyxiated state with elevated CO2

Question 12

What is necessary to open alveoli on first breath during birth?

Answer 12

40-60cm H2O of negative pleural pressure

Question 13

Closure of what structures occur at birth to initiate circulatory changes?

Answer 13

Foramen ovale (atria), ductus arteriosus (great vessles), ductus venosus (bypass liver)

Question 14

How is total peripheral resistance (TPR) affected at birth?

Answer 14

Increased

Question 15

How is pulmonic resistance affected at birth?

Answer 15

Decreased (elimination of hypoxia)

Question 16

What is the effect of altitude on barometric pressure?

Answer 16

Decreased barometric pressure as one ascends

Question 17

At what height is the barometric pressure 47 mmHg (LOW) and the blood “boils”?

Answer 17

63,000 ft

Question 18

Does the amount of oxygen in the air change with altitude?

Answer 18

NO, the partial pressure does

Question 19

As barometric pressure decreases, how does PO2 change?

Answer 19

Decreases, as well

Question 20

How does an unacclimatized person suffer from ascending to great heights?

Answer 20

Deterioration of nervous system function

Question 21

What are some signs and symptoms of hypoxia due to ascending great heights?

Answer 21

Sleepiness, false sense of well being, impaired judgment, clumsiness, blunted pain perception, decreased visual acuity, tremors twitching, seizures.

Question 22

What types of edema are seen with acute mountain sickness?

Answer 22

Cerebral and pulmonary

Question 23

What is the effect of cerebral edema?

Answer 23

Hypoxia and local vasodilatation

Question 24

What is the effect of pulmonary edema?

Answer 24

Hypoxia and local vasoconstriction

Question 25

What receptors are stimulated immediately following exposure to low PO2 at high altitude?

Answer 25

Arterial peripheral chemoreceptors due to hypoxia

Question 26

What condition arises from exposure to low PO2 at high altitude?

Answer 26

Respiratory alkalosis (pH increase)

Question 27

What effects are demonstrated by the increase in pH seen in respiratory alkalosis?

Answer 27

Inhibition of ventilation and opposes the stimulatory effects of hypoxia on peripheral chemoreceptors

Question 28

As inhibition fades from respiratory alkalosis, how does ventilation change?

Answer 28

Increases 5X

Question 29

Why does ventilation increase so much following respiratory alkalosis?

Answer 29

Excretion of HCO3- by kidneys acts to offset decreased CO2 to bring pH back to normal then there is hypoxic unopposed stimulation of peripheral chemoreceptors yet again so ventilation increases

Question 30

How does chronic mountain sickness affect hematocrit (red cell mass)?

Answer 30

Increased

Question 31

How does increased hematocrit affect cardiac blood flow?

Answer 31

Increased viscosity makes it harder to pump the blood

Question 32

What is the effect of chronic mountain sickness on pulmonary arterial blood pressure?

Answer 32

Increased

Question 33

Hypertrophy of which heart chamber is seen in chronic mountain sickness?

Answer 33

Right ventricle

Question 34

How is TPR affected by chronic mountain sickness?

Answer 34

Decreased (due to dilation in tissue beds)

Question 35

What condition can arise from chronic mountain sickness?

Answer 35

Congestive heart failure

Question 36

Why is chronic mountain sickness dangerous?

Answer 36

Fatal is person is not removed to lower altitude

Question 37

What is increased during acclimatization to higher altitudes?

Answer 37

Pulmonary ventilation Hematocrit (RBCs) Diffusing capacity of lungs Tissue vascularity, capillary density Ability of tissues to use O2 (increased mitochondria and cellular oxidative systems) Synthesis of 2,3-DPG (shifts to dissociation)

Question 38

Increased synthesis of 2,3-DPG is an advantage for what part of the body? Disadvantage?

Answer 38

Tissues - advantage | Lung - disadvantage

Question 39

How are people who lives in the Andes and Himalayas able to withstand the high altitudes?

Answer 39

Natural acclimatization that begins in infancy

Question 40

How do those that live in high altitude locations like the Andes and Himalayas differ?

Answer 40

Increased chest to body ratio High ratio of ventilatory capacity to body mass Increased right ventricle Shift in oxy-hemoglobin dissociation curve

Question 41

What is the shift seen in the oxy-hemoglobin dissociation curve in those that live in higher altitudes that have naturally acclimatized?

Answer 41

PO2 of 40 mmHg have greater O2 in blood than lowlanders at 95)

Question 42

Who has a greater work capacity: those naturally acclimatized to high altitudes or well-acclimatized lowlanders at high altitudes?

Answer 42

Naturally acclimatized

Question 43

How does barometric pressure change as we descend beneath the sea?

Answer 43

Increases tremendously

Question 44

How do we avoid lung collapse as we descend below sea level?

Answer 44

Air is supplied at high pressures

Question 45

What is hyperbarism?

Answer 45

Exposing pulmonary capillary blood to extremely high alveolar gas pressures (can be lethal)

Question 46

What is the effect of high nitrogen partial pressure?

Answer 46

Narcosis in about an hour

Question 47

When does nitrogen narcosis lead to dysfunction?

Answer 47

Beyond 250 ft below sea level

Question 48

Nitrogen narcosis is similar to what other sensation?

Answer 48

Alcohol intoxication

Question 49

How does high PN2 affect function?

Answer 49

Nitrogen dissolves in neuronal membranes and alters ionic conductance

Question 50

What is the effect of high PO2?

Answer 50

Seizures followed by coma within 30-60 minutes (lethal to divers)

Question 51

How does high PO2 lead to seizures and coma?

Answer 51

Free radical damage to cell membranes and cellular enzymes

Question 52

What type of tissue is highly susceptible to damage from high PO2 levels?

Answer 52

Nervous tissue

Question 53

How can oxygen toxicity be prevented?

Answer 53

If one never exceeds the established maximum depth of a given breathing gas

Question 54

How do divers avoid oxygen toxicity?

Answer 54

Use hypoxic blends with a lower percentage of O2 than atmospheric air past 180 ft

Question 55

Increased partial pressure of what gas usually isn't a problem with depth?

Answer 55

PCO2 (doesn't increase with depth)

Question 56

What problems can arise from PCO2 being greater than 80 mmHg?

Answer 56

``` Depression of respiratory centers Respiratory acidosis Lethargy Narcosis Anesthesia ```

Question 57

Why is it necessary to ascend to reduce high levels of PN2?

Answer 57

N2 isn't metabolized by the body so it remains dissolved in tissues

Question 58

How long does it usually take for gas pressures of N2 in all body tissues to equilibrate with alveolar PN2?

Answer 58

Several hours

Question 59

What is decompression?

Answer 59

Increased PN2 due to breathing air under high pressure for an extended period of time

Question 60

Why does it take a few hours for PN2 equilibration of tissues?

Answer 60

Blood doesn't flow rapidly enough and N2 doesn't diffuse rapidly enough

Question 61

Does N2 dissolve faster in water or fat?

Answer 61

Water (less than 1 hour)

Question 62

How does decompression sickness affect the circulatory system?

Answer 62

Nitrogen out of fluids creating bubbles that can block many blood vessels (small ones first, then larger ones)

Question 63

What are the signs of symptoms of decompression sickness?

Answer 63

Pain in joints, muscles of arms and legs | Nervous system issues like dizziness, paralysis, unconsciousness

Question 64

How is decompression sickness prevented?

Answer 64

Gradual ascent from lower levels to allow time for body to acclimate (total decompression time = 3 hours)

Question 65

The lung ranks second as an organ of body metabolism behind what other organ?

Answer 65

Liver

Question 66

What is the advantage that the lung has over the liver when it comes to metabolism?

Answer 66

All blood passes through the lungs with every complete cycle

Question 67

What organs receive the greatest blood flow per gram of tissue?

Answer 67

Kidneys (due to their filtration function)

Question 68

What are examples of the lung's metabolic function?

Answer 68

Angiotensin I converted to angiotensin II | Prostaglandins inactivated in one pass through pulmonary circulation