Diving Physiology (ppt) - Dr. Miyake

Question 1

Ambient pressure at sea level

Answer 1

1 atmosphere

Question 2

For every 10 meters of sea water

Answer 2

1 ata

Question 3

O m/ O ft

Answer 3

1 ata/ bar

Question 4

10 m/ 33 ft

Answer 4

2 ata/bar

Question 5

20 m/ 66 ft

Answer 5

3 ata/bar

Question 6

30 m/ 99 ft

Answer 6

4 ata/bar

Question 7

During descent, the volume of a body of air decreases while density ________.

Answer 7

Increases

Question 8

Increased external water pressure does not compress body’s fluid and solid components until a depth of _______.

Answer 8

1.5 km

Question 9

It compresses each of body’s air compartments that depends on the compliance of the compartment.

Answer 9

Increased external water pressure

Question 10

Examples of COMPRESSIBLE:

Answer 10

Middle ear space
Sinuses
Lungs
Bowel lumen

Question 11

According to __________, P and V vary inversely with each other

Answer 11

Boyle’s law

Question 12

Thus, if the chest wall were perfectly compliant, a breath-holding dive to _____ below the surface would double the pressure and compress the air held in the lungs to half its original volume.

Answer 12

10 m

Question 13

Volume of gas is ___________ to pressure to which it is subjected, temperature remaining __________.

Answer 13

Inversely proportional

Constant

Question 14

Diver is exposed when breathing air:

Answer 14

1. Nitrogen
2. Oxygen
3. Carbon dioxide

Question 15

4/5 air

Answer 15

Nitrogen

Question 16

Almost useless as a result of nitrogen narcosis

Answer 16

> 250 ft

Question 17

Normal range of alveolar PO2 below __________, almost none of total oxygen in blood is accounted for by dissolved oxygen.

Answer 17

120 mmHg

Question 18

Has high lipid solubility and dissolves readily in adipocytes and membrane lipids.

Answer 18

Nitrogen

Question 19

Strength wanes, too clumsy to perform the work required.

Answer 19

200-250 ft

Question 20

When PO2 in blood rises _______, amount of O2 dissolved in water of blood increases markedly.

Answer 20

> 100 mmHg

Question 21

Drowsy

Answer 21

150-200 ft

Question 22

As PN2 _______, N2 equilibrates only slowly with body’s lipid stores because adipose tissue is relatively underperfused.

Answer 22

Rises

Question 23

At high pressures can cause degrees of narcosis

Answer 23

Nitrogen

Question 24

Lose many of his/her cares

Answer 24

120 ft

Question 25

Depth at which 1st symptoms of mild nitrogen narcosis is ________.

Answer 25

120 ft

Question 26

As O2 pressures rises into thousands of mmHg, large portion of __________ is then dissolved in water of blood.

Answer 26

Total O2

Question 27

Prolonged elevation has detrimental effects on nonpulmonary tissues including CNS

Answer 27

Acute oxygen poisoning

Question 28

Breathing O2 at 30-40 mmHg will cause BRAIN SEIZURES followed by coma within _________.

Answer 28

30-60 minutes

Question 29

Preliminary symptoms of acute oxygen poisoning:

Answer 29

NMDDID ``` Nausea Muscle twitchings Dizziness Disturbance of vision Irritability Disorientation ```

Question 30

Has little capability of oxidizing other chemical compounds.

Answer 30

Molecular O2

Question 31

Molecular O2 must 1st be converted into ______ form of O2.

Answer 31

Active

Question 32

Forms of active O2 is called ________.

Answer 32

Oxygen free radicals

Question 33

When tissue PO2 is normal at the level of _________ small amounts of free radicals are continually being formed from dissolved molecular O2.

Answer 33

40 mmHg

Question 34

Enzymes rapidly remove free radicals:

Answer 34

Peroxidases Catalaes Superoxide dismutases

Question 35

Above critical alveolar PO2 amounts of ____________ literally swamp enzyme systems and have serious destructive and even lethal effects on cells.

Answer 35

Oxidizing free radicals

Question 36

After only about 12 hours of 1 atm oxygen exposure develops:

Answer 36

Chronic oxygen poisoning

Question 37

Lung passageway congestion, pulmonary edema and atelectasis.

Answer 37

Chronic oxygen poisoning

Question 38

Caused by damage to the linings of bronchi and alveoli begin to develop.

Answer 38

Chronic oxygen poisoning

Question 39

To prevent, divers must reduce fraction of inspired air that is O2 in compressed gas mixture.

Answer 39

Oxygen toxicity

Question 40

A replacement gas

Answer 40

Helium

Question 41

Has only a fraction of narcotizing effect of N2.

Answer 41

Helium

Question 42

Dissolves in tissues to a lesser extent than N2

Answer 42

Helium

Question 43

Has lower density than N2 and this lowers effective airway resistance.

Answer 43

Helium

Question 44

During decompression phase of a dive, _______ diffuses out of tissues more rapidly than does N2 and alleviates most of problems associated with decompression.

Answer 44

Helium

Question 45

If diving gear is properly designed and functions properly, diver has no problem due to CO2 toxicity because depth alone does not __________ CO2 partial pressure in alveoli.

Answer 45

Increase

Question 46

In some types of diving gear ________ can build up in dead space air of apparatus and be rebreathed by diver.

Answer 46

CO2

Question 47

Up to PCO2 of _______ (twice that in normal alveoli) diver usually tolerates this buildup by increasing the minute respiratory volume to compensate for increased CO2

Answer 47

80 mmHg

Question 48

The total amount of new air moved into the respiratory passages each minute _________ on an average.

Answer 48

6 L/min

Question 49

A person will die if minute respiratory volume falls as low as ________ or RR falls below _________.

Answer 49

1.5 L/min | 2-4 breath/min

Question 50

Also known pulmonary ventilation

Answer 50

Minute respiratory volume

Question 51

Beyond ______ PCO2, becomes intolerable and eventually respiratory center begins to be depressed because of negative tissue metabolic effects of high PCO2.

Answer 51

80 mmHg

Question 52

Develops severe respiratory acidosis, lethargy, narcosis and even anesthesia.

Answer 52

Carbon dioxide toxicity

Question 53

Following extended dive, diver must decompress slowly to avoid ____________.

Answer 53

Decompression sickness

Question 54

Serious difficulties also arise if - after a __________ - diver returns to surface too quickly.

Answer 54

Deep saturation dive

Question 55

At end of saturation dive, _______ is at same high value in alveoi and most tissues.

Answer 55

PN2

Question 56

As ______ falls during ascent, alveolar PN2 will fall as well, creating a PN2 gradient from mixed venous blood to alveolar air.

Answer 56

PB - Barometric pressure

Question 57

Washout of N2 from blood creates a PN2 gradient from ______ to _______.

Answer 57

tissues to blood

Question 58

To allow enough tome for dissolved N2 to move from tissues to blood to alveoli, a diver must rise to surface slowly (no faster than _________).

Answer 58

3 m/hr