Respiration: Diving Adaptations Flashcards
what organisms have physiology that allow for extraordinary diving capabilities (5)
- sperm whale
- weddell seal
- elephant seal
- mata-mata turtle
- painted turtles
what occurs to air cavities when animals dive to great depths
- pressure increases, causing air cavities to be squeezed
what determines dive duration (2)
- O2 supply: what’s available
- O2 demand: what’s consumed
how do diving organisms change for diving
- integrated diving reflex
integrated diving reflex
- which organisms possess this
- goal
- consists of…
- 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
integrated diving reflex: diving bradycardia (2)
- selective slowing of the heart
- begins during submersion and ends after emersion
what determines the magnitude of diving bradycardia (2)
- species
- anticipated dive duration
integrated diving reflex: selective peripheral vasoconstriction (2)
- blood flow to non-essential tissues is reduced to selectively distribute O2 stores
- selective reduction in tissue blood flow
selective peripheral vasoconstriction: which body parts experience maintained blood flow (3)
- brain
- retina
- lungs
selective peripheral vasoconstriction:
which body parts experience reduced blood flow (4)
- extremities
- heart
- pancreas
- liver
what happens to mean arterial pressure during diving
- remains relatively constant
why do animals need to vasoconstrict during diving
- minimize pressure/perfusion changes that would occur due to drop in HR
mean arterial pressure formula
- MAP = Q + TPR
mean arterial pressure formula: Q (2)
- cardiac output
- defined by heart rate * stroke volume
mean arterial pressure formula: TPR (2)
- total peripheral resistance
- resistance of all blood vessels in body
can mammals and birds alter stroke volume
- they have limited capacity to alter stroke volume
how will an 80% reduction in HR affect MAP and TPR (2)
- 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)
aerobic dive limit (2)
- 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
which vertebrates tend to exceed aerobic dive limit
- some birds that exploit prey rich environments
how do levels change during dives
- heart rate
- cardiac output
- blood CO2 content
- blood oxygen content
- decreases
- decreases
- increases
- decreases
anaerobic dive: lactate (2)
- 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
aerobic dive: lactate
- no lactate produce, so lactate pulse is not evident
volume and pressure relationship
- volume is inversely proportional to pressure
what happens to the volume of the lungs as pressure/depth increases
- volume of lungs decreases non-linearly
PO2/PN2 and pressure relationship
- changes in PO2/PN2 in lungs are directly proportional to pressure
what happens to PO2 of the lungs as pressure/depth increases
- PO2 of lungs increases linearly
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
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
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
excess O2 in body
- easily metabolized and does not pose as a problem
excess N2 in body (2)
- not easily metabolized and must come out of body
- can serve as a problem
what is the “bends”
- decompression sickness
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
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
what do gas bubbles need to form (2)
- require a nucleus to come out of solution
- once formed, they can expand rapidly
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
where can bubbles formed from decompression be visualized in humans
- visible in tear fluid beneath contact lenses
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
