Exam 3 - Hypo/hyperbaric Enironments

Question 1

Percentages of atmospheric oxygen, carbon dioxide and nitrogen

Answer 1

O2 = 20.93%
CO2 = 0.03%
N = 79%

Question 2

How does diving disrupt homeostasis?

Answer 2

Disrupts internal pressure and gas concentrations within the body. Alteration in bod fluid composition and movement.

Question 3

Regulation of internal pressure and gas concentration relies on…

Answer 3

CV an respiratory system. Injury occurs if unable to adapt.

Question 4

Hyperbaric Environment

Answer 4

Pressure is greater than air pressure on sea level

Question 5

Five physiologic stresses the body faces in hyperbaria

Answer 5

Elevated ambient pressure, decreased effects of gravity, altered respiration, hypothermia, sensory impairment

Question 6

Hyperventilation

Answer 6

Prolongs time to break-point. Decreased CO2, increased O2 (arterial)

Question 7

Chemoreceptors respond to

Answer 7

Decreased O2 (arterial), increased PCO2 (arterial) and decreased pH

Question 8

Boyle’s Law

Answer 8

At a constant temperature, the absolute pressure and volume of a gas are inversely proportional.

Question 9

Henry’s Law

Answer 9

Increased partial pressure = increased gas dissolved in tissue. O2 and CO2 diffusion.

Question 10

Dalton’s Law

Answer 10

Increased ambient pressure = increased partial pressure of PO2 and PCO2

Question 11

Where is the respiratory control center located?

Answer 11

Within medulla oblongata

Question 12

Respiratory center comprised of two dense clusters of neurons

Answer 12

Dorsal respiratory center - primarily inspiratory neurons (control diaphragm and receive feedback on PO2, PCO2 and pH) Ventral respiratory center - both inspiratory and expiratory neurons (controls all breathing muscles)

Question 13

Mechanics of breathing (immersion up to neck)

Answer 13

When immersed up to the neck, there is increased pressure placed on chest. Normal outward elastic recoil of chest is decreased.

Question 14

Pulmonary blood flow (immersion up to neck)

Answer 14

Blood pooling will be decreased due to increased pressure - enhanced venous return. Colder water enhances venous return.

Question 15

Mechanics of breathing (underwater breathing)

Answer 15

At great depths, density of gas increases, thus increasing airway resistance. Sensitivity to CO2 is decreased.

Question 16

Diving Reflex

Answer 16

Induces bradycardia and increases vascular resistance

Question 17

BHD Medical Considerations

Answer 17

Decreased CO2 minimizes urge to breath. O2 remains high during descent. Bottom phase CO2 rises which may cause loss of conciousness due to hypoxia.

Question 18

Lung Squeeze

Answer 18

Excess pressure on the lungs causes fluid to move into the lungs. S/S Shortness of breath, coughing up blood, pulmonary edema.

Question 19

Alveolar Rupture

Answer 19

Excess of movement of fluid into lungs may cause alveoli rupture. S/S: Shortness of breath.

Question 20

Barotrauma

Answer 20

Gas expansion in the GI tract. S/S: Abdominal pain, belching, flatulence.

Question 21

Pneomothorax

Answer 21

Ruptured lungs tissue allows a pocket of air to form between the pleura of the lungs. S/S: Shortness of breath, collapsed lungs.

Question 22

Middle-ear squeeze

Answer 22

Closed eustachian tube does not allow for pressure between the middle and air in the lungs to equalize. S/S: Pain in the ear, blood around ear, nose or mouth.

Question 23

Air Embolism

Answer 23

Expansion of lung gasses during ascent.

Question 24

O2 Toxicity

Answer 24

Exposure to high oxygen for high periods of long periods of time. S/S: Primarily occur within the lungs, CNS.

Question 25

Nitrogen Narcosis

Answer 25

Increased nitrogen diffusion into tissues. S/S: Poor judgement, slow reaction time, euphoria.

Question 26

Decompression Sickness

Answer 26

If ascent occurs too quickly, excess N and O in the tissues will result increased pressure ultimately blocking blood and lumph vessels, inducing compartment syndrome, and rupturing cell membranes.

Question 27

CO2 Toxicity

Answer 27

Hypoxia, hypercapnia occurs during closed-circuit suba. S/S: Breathlessness, increased VE, impaired mental function and unconciousness.

Question 28

Hypoxia

Answer 28

Occurs when their is insufficient O2 supply to tissues.

Question 29

Hypobaria

Answer 29

Altitude. Total pressure is less than that at sea level.

Question 30

High Altitude

Answer 30

1500-3499m (4291-11483feet)

Question 31

Very High Altitude

Answer 31

3500-5500m (11,500-18,000 feet)

Question 32

Extreme Altitude

Answer 32

More then 5500m. 5985m is the population at highest altitude.

Question 33

Bohr Effect

Answer 33

Saturation of Hb with O2 at various PO2 values. Influenced by temperature and pH. Normal conditions: 60-100mmHg, Hb will be completely saturated.

Question 34

Effects of of altitude on Bohr Effect

Answer 34

Goes right at first then left. As pressure increases, % saturation increases (toxicity). A shift to the left is desired (increase saturation, increased partial pressure). Cool and basic preferred.

Question 35

2,3-Diphosphoglycerate (DPG)

Answer 35

Positive effect, increases with high altitude, makes it easier for hemoglobin to release its O2.

Question 36

Exposure to altitude will result in hypoxia...

Answer 36

Decreased rate of oxygen utilization by cells. Body relies on anaerobic means for rephosphorylation of ATP.

Question 37

Respiratory Response to Altitude

Answer 37

Hyperventilation, Respiratory alkalosis (hypercapnia), VE increases.

Question 38

Cardiovascular Response to Altitude

Answer 38

Q increases due to HR increase, decreased plasma volume, SV decreases slightly (venous return, contractility maintained), a-VO2 increased, increased polycythemia (stimulated by EPO in kidneys)

Question 39

Central Nervous Response to Altitude

Answer 39

Alterations in vision, hearing, motor skills, memory, mood and hallucinations. Activities require more time and concentration.

Question 40

Metabolism Changes at Altitude

Answer 40

Weight loss attributed to hypoxia/AMS (loss of appetite), protein metabolism inhibited, focus on physical tasks without eating or drinking, increased caloric expenditure.

Question 41

Altitude on Sleep

Answer 41

Impaired by altitude and hypoxic stress.

Question 42

Immediate Responses to Changes in Altitude

Answer 42

Hyperventilation, increased Q and decreased VO2, increased EPI, increased fluid loss, decreased in mental and sensory function.

Question 43

Long-Term Responses to Altitude

Answer 43

Body fluids become more basic, decreased plasma volume, increased RBC, increased mitochondria, O2 release at tissues, decrease in lean body mass and body fat.

Question 44

Altitude and Performance

Answer 44

Aerobic decreases due to ventilatory limitations and then improves, muscular strength and sprinting unaffected, maximal aerobic can only be maintained for short periods.

Question 45

Recommendations for Training?

Answer 45

Live high, train low! Lower intensity until acclimatized.

Question 46

Anaerobic Performance and Altitude

Answer 46

May decrease slightly or remain unchanged.

Question 47

Benefits of training at altitude

Answer 47

Increased arterial O2 reduces occurrence of hypoxia, increased sensitivity of chemoreceptors, polycythemia, increased bone marrow (increased RBC production), decreased muscle CSA (less energy for more work), increased aerobic metabolism.

Question 48

Deacclimatization

Answer 48

Occurs 2 weeks after returning to sea level.

Question 49

Acute Mountain Sickness

Answer 49

Develops 6-12 hours following rapid ascent, peaks within 24-48 hours, acclimatization takes 3-7 days

Question 50

S/S of AMS

Answer 50

Vascular changes (kidneys) can cause headache, fatigue, instability, GI distress (nausea, vomiting, diarrhea, loss of appetite) *EAT CARBS

Question 51

Treatment of AMS

Answer 51

Descend, Acetazolamide, Supplemental O2

Question 52

High-Altitude Cerebral Edema (HACE)

Answer 52

Extreme form of AMS can result in loss of conciousness, occurs between 12 hours and three days as a result of increased intracranial pressure

Question 53

S/S of HACE

Answer 53

Loss of coordination, AMS symptoms/treatment, loss conciousness.

Question 54

High-Altitude Pulmonary Edema (HAPE)

Answer 54

Occurs 12-96 hours post-ascent.

Question 55

S/S of HAPE

Answer 55

Excessive, rapid breathing, increased HR, bloody cough, cyanosis (blue skin color)

Question 56

PREVENTION of HAPE

Answer 56

Acetazolimide, ascend slowly, sleep at lower altitudes, minimize PA.