Respiration: Diving Adaptations Flashcards

1
Q

what organisms have physiology that allow for extraordinary diving capabilities (5)

A
  • sperm whale
  • weddell seal
  • elephant seal
  • mata-mata turtle
  • painted turtles
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2
Q

what occurs to air cavities when animals dive to great depths

A
  • pressure increases, causing air cavities to be squeezed
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3
Q

what determines dive duration (2)

A
  • O2 supply: what’s available
  • O2 demand: what’s consumed
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4
Q

how do diving organisms change for diving

A
  • integrated diving reflex
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5
Q

integrated diving reflex
- which organisms possess this
- goal
- consists of…

A
  • present in all mammals, and well-developed in diving mammals
  • done so O2 is distributed to most essential organs, while minimizing cardiac expenditure
  • consists of diving bradycardia and selective peripheral vasoconstriction
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6
Q

integrated diving reflex: diving bradycardia (2)

A
  • selective slowing of the heart
  • begins during submersion and ends after emersion
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7
Q

what determines the magnitude of diving bradycardia (2)

A
  • species
  • anticipated dive duration
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8
Q

integrated diving reflex: selective peripheral vasoconstriction (2)

A
  • blood flow to non-essential tissues is reduced to selectively distribute O2 stores
  • selective reduction in tissue blood flow
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9
Q

selective peripheral vasoconstriction: which body parts experience maintained blood flow (3)

A
  • brain
  • retina
  • lungs
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10
Q

selective peripheral vasoconstriction:
which body parts experience reduced blood flow (4)

A
  • extremities
  • heart
  • pancreas
  • liver
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11
Q

what happens to mean arterial pressure during diving

A
  • remains relatively constant
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12
Q

why do animals need to vasoconstrict during diving

A
  • minimize pressure/perfusion changes that would occur due to drop in HR
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13
Q

mean arterial pressure formula

A
  • MAP = Q + TPR
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14
Q

mean arterial pressure formula: Q (2)

A
  • cardiac output
  • defined by heart rate * stroke volume
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15
Q

mean arterial pressure formula: TPR (2)

A
  • total peripheral resistance
  • resistance of all blood vessels in body
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16
Q

can mammals and birds alter stroke volume

A
  • they have limited capacity to alter stroke volume
17
Q

how will an 80% reduction in HR affect MAP and TPR (2)

A
  • Q will drop by 80% (Q = 0.2)
  • to maintain pressure to ensure blood flow to essential tissues, resistance must increase by 500% (5-fold increase)
18
Q

aerobic dive limit (2)

A
  • dive time where lactate begins to accumulate as a result of the switch to anaerobic metabolism
  • most diving vertebrates do not exceed durations where dive requires anaerobic metabolism
19
Q

which vertebrates tend to exceed aerobic dive limit

A
  • some birds that exploit prey rich environments
20
Q

how do levels change during dives
- heart rate
- cardiac output
- blood CO2 content
- blood oxygen content

A
  • decreases
  • decreases
  • increases
  • decreases
21
Q

anaerobic dive: lactate (2)

A
  • lactate is retained in tissues
  • lactate is not removed until after the dive, so blood lactate concentration experiences a spike during recovery after the dive
22
Q

aerobic dive: lactate

A
  • no lactate produce, so lactate pulse is not evident
23
Q

volume and pressure relationship

A
  • volume is inversely proportional to pressure
24
Q

what happens to the volume of the lungs as pressure/depth increases

A
  • volume of lungs decreases non-linearly
25
PO2/PN2 and pressure relationship
- changes in PO2/PN2 in lungs are directly proportional to pressure
26
what happens to PO2 of the lungs as pressure/depth increases
- PO2 of lungs increases linearly
27
what happens to lung volume and total gas pressure (PO2, PN2) in SCUBA divers
- lung volume remains constant at different depths - total gas pressure increases in proportion to depth
28
what occurs to SCUBA diver during descent and what laws explain these changes (2)
- inhaled PO2 and PN2 increase and tissues will equilibrate to this - Henry's and Dalton's laws
29
what occurs to SCUBA divers during ascent (3)
- inhaled PO2 and PN2 decrease - gases in tissues are supersaturated relative lungs - excess nitrogen and oxygen leave blood and tissues
30
excess O2 in body
- easily metabolized and does not pose as a problem
31
excess N2 in body (2)
- not easily metabolized and must come out of body - can serve as a problem
32
what is the "bends"
- decompression sickness
33
bends: when does it occur
- occurs when rate of ascent is faster than blood can excrete gases into the lung - causes small bubbles of gas form spontaneously in the body
34
bends: symptoms (2)
- blockage of blood flow by bubbles to joints by the bubbles causes pain - blockage of blood flow by bubbles to nervous tissue can cause paralysis or stroke
35
what do gas bubbles need to form (2)
- require a nucleus to come out of solution - once formed, they can expand rapidly
36
decompression chambers (2)
- hyperbaric chamber that increases pressure to allow bubbles to dissolve back into blood - followed by slow decrease in pressure so that excess gas can be excreted by lungs and bubbles do not form
37
where can bubbles formed from decompression be visualized in humans
- visible in tear fluid beneath contact lenses
38
how does air and water act below dams/waterfalls (2)
- air bubbles are taken to depth and equilibrate at depth - when water moves to surface, it is supersaturated with gases