Physiology

Question 1

Blood

Oxygen is efficiently transported throughout the body because of a substance called _____________, which is contained in the _____________.

a) oxidative metabolism/blood
b) plasma/arteries
c) protein/heart
d) haemoglobin/red blood cells

Answer 1

d) haemoglobin/red blood cells

Question 2

Blood

If the blood did not contain hemoglobin, it would have to circulate 15 to 20 times faster to keep up with the body’s demand for oxygen.
True
False

Answer 2

True

Question 3

Blood

Large amounts of carbon dioxide can be carried by the circulatory system back to the lungs for expiration primarily because carbon dioxide:

a) can easily dissolve in the plasma.
b) can easily combine with the haemoglobin.
c) can be converted into bicarbonate.
d) is an inert gas like nitrogen.

Answer 3

c) can be converted into bicarbonate.

Question 4

Responses to Breathing with Equipment

The practice of breathing deeply when scuba diving is important in order to compensate for the:

a) increased dead-air space resulting from the snorkel or regulator.
b) reduced lung volume resulting from compression of the chest.
c) increased amount of alveolar carbon dioxide.
d) All of the above are correct.

Answer 4

d) All of the above are correct.

Question 5

Responses to Breathing with Equipment

The practice of breathing slowly when scuba diving is important in order to:

a) minimize resistance caused by turbulence in the airways.
b) compensate for the decrease in energy from immersion in cold water.
c) avoid the potential for thoracic squeeze.
d) All of the above are correct.

Answer 5

a) minimize resistance caused by turbulence in the airways.

Question 6

Responses to Breath-Hold Diving

When a breath-holding diver submerges in cold water, his heart rate will:

a) increase
b) decrease
c) remain unchanged
d) fluctuate

Answer 6

b) decrease

Question 7

Responses to Breath-Hold Diving

To reduce the demand for oxygen while breath-hold diving, the diver should:

a) breathe pure oxygen before submerging.
b) move slowly and deliberately while underwater.
c) take a few rapid deep breaths before submerging.
d) All of the above are correct.

Answer 7

b) move slowly and deliberately while underwater.

Question 8

Responses to Breath-Hold Diving

Breathing slowly from the diaphragm before a breathhold dive can:

a) promote relaxation.
b) promote better gas exchange.
c) reduce proportional dead air volume.
d) All of the above are correct.

Answer 8

d) All of the above are correct.

Question 9

Hypocapnia

The reflex respiratory center regulates breathing based primarily on the level of _____________ in the blood.

a) oxygen
b) nitrogen
c) carbon dioxide
d) All of the above depending upon circumstance.

Answer 9

c) carbon dioxide

Question 10

Hypocapnia

Hypoxia results when the diver’s carbon dioxide level cannot accumulate to a level high enough to stimulate breathing before the tissues consume the available oxygen.
True
False

Answer 10

True

Question 11

Hypocapnia

Blackout normally occurs on ascent because:

a) the diver’s energy expenditure increases.
b) the partial pressure of the alveolar oxygen rapidly decreases.
c) the partial pressure of the alveolar carbon dioxide rapidly decreases.
d) the decreasing pressure causes a carotid sinus reflex.

Answer 11

b) the partial pressure of the alveolar oxygen rapidly decreases.

Question 12

Carotid-Sinus Reflex

The carotid-sinus receptors, which are located in the carotid arteries, stimulate the _____________, which is located in the _____________.

a) thyroid/throat
b) cardioinhibitory center/brain
c) S-A node/heart
d) adrenal glands/kidneys

Answer 12

b) cardioinhibitory center/brain

Question 13

Carotid-Sinus Reflex

The carotid-sinus reflex is caused by an excessively tight

a) exposure suit or boots that constrict the feet.
b) exposure suit that constricts the thorax.
c) exposure suit or hood that constricts the neck.
d) mask strap that constricts the head.

Answer 13

c) exposure suit or hood that constricts the neck.

Question 14

Carotid-Sinus Reflex

When the carotid-sinus receptors detect high pressure, they cause the heart to

a) slow down.
b) speed up.
c) stop momentarily.
d) increase pressure.

Answer 14

a) slow down.

Question 15

Carbon Monoxide Poisoning

Carbon monoxide is difficult to detect because it

a) is inert.
b) has a sedating effect on the diver.
c) is odourless and tasteless.
d) All of the above are correct.

Answer 15

c) is odourless and tasteless.

Question 16

Carbon Monoxide Poisoning

Carbon monoxide bonds with hemoglobin over _____________ times more readily than oxygen can, and takes _____________ for the circulatory system to eliminate.

a) 200/8-12 hours
b) 100/4-6 hours
c) 50/2-4 hours
d) 20/30 minutes

Answer 16

a) 200/8-12 hours

Question 17

Carbon Monoxide Poisoning

The symptoms of carbon monoxide poisoning are not as noticeable at depth because

a) high levels of oxygen are dissolved in the plasma allowing tissues to meet their oxygen requirement.
b) high levels of nitrogen sedate the diver’s central nervous system slowing his metabolism.
c) lower levels of carbon dioxide help to counteract the effects of carbon monoxide.
d) lower levels of oxygen make the brain less sensitive and alert.

Answer 17

a) high levels of oxygen are dissolved in the plasma allowing tissues to meet their oxygen requirement.

Question 18

Carbon Monoxide Poisoning

Smoking cigarettes prior to diving can raise the carbon monoxide level _____________ times above normal, which in turn _____________.

a) 2/makes it harder to breath
b) 3-12/impairs oxygen transport and carbon dioxide elimination
c) 20-40/increases the risk of a lung-expansion injury
d) 100/increases the risk of heart attack and stroke

Answer 18

b) 3-12/impairs oxygen transport and carbon dioxide elimination

Question 19

Inert Gas Absorption

What factors cause body tissues to absorb and eliminate nitrogen at different rates? (choose all that apply)

a) High or low blood supply
b) Distance from skin surface
c) Tissue density
d) Distance from lungs

Answer 19

a) High or low blood supply

c) Tissue density

Question 20

Inert Gas Absorption

Decompression sickness occurs in recreational divers upon surfacing rather than at depth because _________ does not occur in body tissues until the ambient pressure is reduced.

a) saturation
b) supersaturation
c) silent bubbling
d) diffusion

Answer 20

b) supersaturation

Question 21

Inert Gas Absorption

Divers succumb to decompression sickness because in humans any amount of supersaturation of the tissues with nitrogen will result in significant bubble formation.
True
False

Answer 21

False

Question 22

Inert Gas Absorption

The various factors that increase the diver’s susceptibility to decompression sickness relate primarily to

a) tissue half-times.
b) physical conditioning.
c) changes to respiration.
d) changes to circulation.

Answer 22

d) changes to circulation.

Question 23

Inert Gas Release

The term “silent bubbles” refers to bubbles that:

a) do not move - such as those that cause decompression sickness in the joints.
b) cannot be heard with any form of electronic sensors.
c) are so small they do not cause signs and symptoms of decompression sickness.
d) appear and disappear very quickly.

Answer 23

c) are so small they do not cause signs and symptoms of decompression sickness.

Question 24

Inert Gas Release

What is the device used to detect the presence of silent bubbles?

a) Stethoscope
b) Haldanean Monitor
c) Recreational Dive Planner
d) Doppler Ultrasound Flowmeter

Answer 24

d) Doppler Ultrasound Flowmeter

Question 25

Inert Gas Release

Silent bubbles are thought to form because of the presence of

a) fat particles in the blood stream.
b) impurities in the diver’s air supply.
c) gas “seeds” (micronuclei).
d) changes in blood chemistry brought about by high levels of nitrogen.

Answer 25

c) gas “seeds” (micronuclei).

Question 26

Inert Gas Absorption

Decompression sickness is caused by nitrogen bubbles, but why don’t oxygen bubbles also form?

a) Oxygen is used up in the body’s metabolic process.
b) There is more nitrogen in air than oxygen.
c) Oxygen binds tightly with haemoglobin.
d) It’s unknown.

Answer 26

a) Oxygen is used up in the body’s metabolic process.

Question 27

Inert Gas Absorption

Breathing pure oxygen aids the individual with decompression sickness because it

a) enables the body to metabolize nitrogen more quickly.
b) increases the pressure gradient between the nitrogen pressure in the tissues and the alveolar nitrogen pressure.
c) decreases the pressure gradient between the nitrogen pressure in the tissues and the alveolar nitrogen pressure.
d) helps reduce the size of the bubbles.

Answer 27

b) increases the pressure gradient between the nitrogen pressure in the tissues and the alveolar nitrogen pressure.

Question 28

Gas Narcosis

It is believed that nitrogen (gas) narcosis results from

a) disruptions in the transmissions between nerve cells.
b) extravascular bubble formation in the brain.
c) a severely decreased sensitivity to pain caused by silent bubbles.
d) mechanisms that are completely unknown to science.

Answer 28

a) disruptions in the transmissions between nerve cells.

Question 29

Gas Narcosis

The signs and symptoms of gas narcosis normally begin to occur at approximately what depth?

a) 15 metres/50 feet
b) 30 metres/100 feet
c) 45 metres/150 feet
d) 60 metres/200 feet

Answer 29

b) 30 metres/100 feet

Question 30

Gas Narcosis

What are signs or symptoms of gas narcosis? (choose all that apply)

a) Poor judgment
b) Decreased coordination
c) A feeling of false security
d) Joint pain

Answer 30

a) Poor judgment
b) Decreased coordination
c) A feeling of false security

Question 31

Problems in Body Air Spaces

The term barotrauma literally means

a) pressure injury.
b) ear injury.
c) serious injury.
d) chest injury.

Answer 31

a) pressure injury.

Question 32

Problems in Body Air Spaces

Other than potential damage to the eardrum, an excessively forceful Valsalva manoeuvre can result in a(n)

a) oval window rupture.
b) round window rupture.
c) eustachian tube rupture.
d) All of the above are correct.

Answer 32

b) round window rupture.

Question 33

Problems in Body Air Spaces

Severe lung squeeze can occur in shallow depths in which of the following conditions?

a) A skin (breath-hold) diver hyperventilates prior to descent.
b) A scuba diver descends taking excessively large breaths.
c) A skin diver (breath-hold) descends with a normal lung volume.
d) A skin diver descends with his lungs nearly empty.

Answer 33

d) A skin diver descends with his lungs nearly empty.

Question 34

Summary of Ear and Sinus Barotrauma Treatment

Vertigo is a medical term meaning

a) dizziness.
b) infection of the inner ear.
c) the inability to hear.
d) the ear drum has been ruptured.

Answer 34

a) dizziness.

Question 35

Summary of Ear and Sinus Barotrauma Treatment

Vertigo can be caused by

a) ear squeeze.
b) inner ear barotrauma.
c) decompression sickness.
d) All of the above are correct.

Answer 35

d) All of the above are correct.

Question 36

The Ears

Sound vibrations are transferred from the outer to the inner ear via the

a) oval window.
b) round window.
c) cochlea.
d) ossicles.

Answer 36

d) ossicles.

Question 37

The Ears

The vestibular canals are located in the_____________ and are responsible for _____________.

a) inner ear/balance
b) middle ear/sound transmission
c) outer ear/channeling sound waves to the ear drum
d) brain/transmitting nerve impulses (sound)

Answer 37

a) inner ear/balance

Question 38

The Ears

Which portion of the ear is most affected by changes in pressure?

a) outer ear
b) middle ear
c) inner ear
d) All areas are equally affected.

Answer 38

b) middle ear

Question 39

Decompression Sickness and Lung Overexpansion Injuries

A symptom of air embolism may be _____________, while two symptoms of decompression sickness may be _____________ and _____________.

a) pain in the joints/fatigue and sudden unconsciousness
b) sudden unconsciousness/pain in the joints and fatigue
c) coughing of bloody froth/dizziness and confusion
d) cherry red nail beds/paralysis and dizziness

Answer 39

b) sudden unconsciousness/pain in the joints and fatigue

Question 40

Decompression Sickness and Lung Overexpansion Injuries

In terms of the location of symptoms, air embolism is characterized by _____________, while decompression sickness is characterized by _____________.

a) involvement of the head and neck/involvement of the arms and legs
b) involvement of the respiratory center/involvement of the central nervous system
c) involvement of both sides of the body - either upper or lower/involvement of only one side of the body
d) involvement of only one side of the body/involvement of both sides of the body - either upper or lower

Answer 40

d) involvement of only one side of the body/involvement of both sides of the body - either upper or lower

Question 41

Decompression Sickness and Lung Overexpansion Injuries

In terms of the change in symptoms, air embolism is characterized by _____________, while decompression sickness is characterized by _____________.

a) symptoms tending to improve as a result of first aid/usually no change or worsening of condition
b) usually no change or worsening of condition/symptoms tending to improve as a result of first aid
c) gradual worsening over time/gradual improvement over time
d) gradual improvement over time/gradual worsening over time

Answer 41

a) symptoms tending to improve as a result of first aid/usually no change or worsening of condition

Question 42

Lung Overexpansion Injuries

The most serious form of lung overexpansion injury is a(n) _____________ because air bubbles enter the _____________.

a) pneumothorax/thorax
b) pneumothorax/lung tissues
c) air embolism/arterial circulation
d) air embolism/venous circulation

Answer 42

c) air embolism/arterial circulation

Question 43

Lung Overexpansion Injuries

Even when breathing normally a diver could suffer from a lung overexpansion injury.
True
False

Answer 43

True

Question 44

Lung Overexpansion Injuries

Surfactant is a substance that coats the inner surfaces of the _____________ and helps prevent them from _____________.

a) bronchioles and alveoli/rupturing
b) bronchioles and alveoli/collapsing
c) veins and arteries/collapsing
d) veins and arteries/rupturing

Answer 44

b) bronchioles and alveoli/collapsing