FC4: Diving (W13a) Flashcards

1
Q

Challenges that air-breathing vertebrates have to deal with during submersion/diving? (2)

A

• High pressures underwater.
• Low O2 supply.

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2
Q

High pressures underwater attributes? (3)

A

• Increases with gases compressed.
• Sea level pressure = 1atm.
• Increases by 1atm every 10m in depth.

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3
Q

Problems accompanying diving? (5)

A

• High pressures.
• “The Bends”.
• O2 toxicity.
• Narcotic effect of gases.
• Low O2 supply.

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4
Q

The Bends is AKA? (2)

A

• Diver’s disease.
• Decompression sickness.

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5
Q

The Bends?

A

= condition caused by the formation of gas bubbles in the tissues & blood.

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6
Q

How does supersaturation occur in the Bends?

A

Because the diver experiences pressures twice as that of the surface, these high pressures cause gases to become more soluble & more nitrogen moves into the blood and tissues, therefore creating a supersaturated solution.

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7
Q

What increases the risk of Diver’s disease/Risk factors of Diver’s disease? (6)

A

• Rapid ascent.
• Long dives.
• Deep dives.
• High body fat.
• Age.
• Exercise during dive.

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8
Q

Decompression sickness treatment?

A

Recompression chamber.

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9
Q

What does Diver’s disease cause?

A

Barotrauma.

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10
Q

Difference between diving humans & diving mammals?

A

Diving humans breathe through an O2 tank underwater, while diving mammals exhale before diving.

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11
Q

Lung modifications of marine mammals? (4)

A

• Flexible chest wall (short & thick airways).
• Reinforcement of peripheral airways (bronchioles & trachea).
• Loss of respiratory bronchioles.
• Branchial sphincters.

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12
Q

What do diving mammals do before they enter water?

A

They exhale at the beginning of each dive.

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13
Q

Analogy of Diver’s disease?

A

Carbonated drink.

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14
Q

Why do divers take scuba tanks with Increased Helium?

A

It’s because Helium is less soluble & diffuses much faster than Nitrogen, therefore reducing the development of The Bends.

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15
Q

Contents of scuba tanks? (2)

A

• Reduced Nitrogen.
• Increased Helium.

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16
Q

How is High body fat a risk factor?

A

It’s because it requires such divers to degas for longer periods.

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17
Q

Symptoms of Decompression sickness? (4)

A

• Itching skin (external).
• Strong pain & aching muscles (bone).
• Hallucinations (brain).
• Acute respiratory depression (bloodstream).

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18
Q

Why do diving mammals exhale at the beginning of each dive?

A

It’s so that their lungs collapse completely under high water pressure, which helps reduce buoyancy.

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19
Q

O2 toxicity attributes? (4)

A

• Toxic limit of O2>1atm.
• Increased time (hrs) = Less O2 partial pressure inspired.
• Pulmonary limit (5atm of breathing 20% O2).
• CNS limit.

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20
Q

Narcotic effect of gases attributes? (2)

A

• Physiological & mental disturbances (“Martini effect”).
• He is used as the rate of diffusion is faster (moves out of body quicker due to low molecular weight).

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21
Q

O2 supply attributes? (4)

A

Enables longer duration underwater by:

• Increased O2 storage.
• Anaerobic processes.
• Decrease O2 consumption by lowering MR.
• Aquatic respiration.

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22
Q

O2 storage?

A

= site where you can find respiratory pigments.

23
Q

Problem with using Anaerobic processes to extend time underwater?

A

It takes glycolysis & increases lactic acid formation.

24
Q

How do aquatic reptiles extend time underwater? (2)

A

• Cutaneous respiration.
• Oesophageal/rectal respiration.

25
Q

Places where O2 stored in diving animals? (3)

A

• Lungs (induces buoyancy but is limited).
• Blood (via haemoglobin).
• Muscles (via myoglobin).

26
Q

Where is most of O2 stored (80-90%)? (2)

A

• Blood (via haemoglobin).
• Muscle (via myoglobin).

27
Q

How is O2 supply possible? (2)

A

Through diving mammals having:

• Increased volumes of blood (hematocrit) & erythrocytes.
• High concentrations of myoglobin in their locomotor muscles.

28
Q

Diving animals adaptations for extended diving? (2)

A

• O2 storage.
• Diving reflex.

29
Q

Benefits of diving reflex? (2)

A

• Increases diving duration.
• Uses less energy.

30
Q

Diving reflex attributes? (5)

A

• Reduced need to breathe (apnea).
• Decrease in heart rate (bradycardia) during submersion.
• Hypometabolism.
• Regional hypothermia.
• Only vital organs receive blood (vasoconstriction & no blood to muscles).

31
Q

Which vital organs is blood redirected to during the diving reflex? (2)

A

• Brain.
• Heart.

32
Q

Apnea (diving reflex) function?

A

Prevents aspiration of water.

33
Q

Bradycardia (diving reflex) function?

A

Redirects blood to the brain & heart.

34
Q

Function of only vital organs receiving blood (diving reflex)?

A

Helps balance vasoconstriction.

35
Q

Aerobic dive limit?

A

= dive duration beyond which lactate concentration increases.

36
Q

Aerobic dive limit graph attributes? (6)

A

• More time into dive, Less myoglobin saturation.
• Anaerobic respiration during deep dive.
• Organism lowers MR & switches to glycolysis (anaerobic) metabolism.
• 80% anaerobic metabolism.
• More blood lactate at end of the dive.
• O2 breaks down lactate & repays O2 debt.

37
Q

Diving locomotion attributes? (4)

A

• Less muscle energy requirements.
• Propulsion & gliding.
• 75% ascent gliding.
• 50% energy saving.

38
Q

Result of measuring MR in diving species?

A

Total cost per stroke is double the maximum Volume of O2.

39
Q

How do diving birds dive?

A

They swim using the same biochemical system used for flight (burst & then glide).

40
Q

Diving birds mechanism is AKA?

A

Aqua flying.

41
Q

Egs of diving birds? (2)

A

• Ducks.
• Penguins (Emperor penguins).

42
Q

Feathers of diving birds?

A

Well oiled to trap air (insulation).

43
Q

Subsurface swimming vs Surface swimming?

A

More energetically expensive than surface swimming as it needs 95% work to overcome buoyancy & drag.

44
Q

Diving birds attributes? (2)

A

• Manage blood & respiratory O2 O2 stores (switch to anaerobic muscle fibres).
• Extreme hypoxic tolerance.

45
Q

Diving ectotherms/reptiles attributes? (4)

A

• Don’t go as deep.
• Can stay down much longer (low MR, low O2 use).
• Aren’t found in the Arctic or Antarctic (most limited to tropical waters).
• Don’t change hematocrit (more varied response).

46
Q

Egs of diving ectotherms/reptiles? (3)

A

• Sea snakes.
• Turtles.
• Marine iguanas.

47
Q

Sea snakes attributes? (5)

A

• Aerobic metabolism.
• Cutaneous respiration.
• Compress lungs to decrease buoyancy.
• No diving response (bradycardia).
• Right-to-left shunt.

48
Q

Cutaneous respiration in sea snakes attributes? (3)

A

• Effective after shedding.
• 30% O2 uptake.
• 90% CO2 excretion.

49
Q

Turtles attributes? (4)

A

• Oesophageal or rectal respiration.
• Some may enter dormant states 10-15m below sea.
• Longest aerobic dives (7hrs).
• Leatherbacks are endothermic.

50
Q

Leatherbacks being endothermic traits? (3)

A

• Flipper stroke increases in cold water.
• Subdural fat.
• Countercurrent heat exchange in flippers.

51
Q

Explain mystery question:

Do diving animals get “The Bends”?

A

Although diving mammals fo not experience the Bends due to their adaptations, they are still sensitive to it due to military sonars (which cause them to dive deeper, longer & faster).

52
Q

Impact of sonars on whales & dolphins? (3)

A

• Mass stranding of whales & dolphins.
• Continuous stroking (30% increase in MR).
• Autopsies of stranded whales reveal gas bubbles in tissues.

53
Q

Egs of diving mammals impacted by military sonars? (3)

A

• Cuvier’s beaking whale.
• Dolphins.
• Seals.