Respiration: Diving Adaptations

Question 1

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

Answer 1

• sperm whale
• weddell seal
• elephant seal
• mata-mata turtle
• painted turtles

Question 2

what occurs to air cavities when animals dive to great depths

Answer 2

• pressure increases, causing air cavities to be squeezed

Question 3

what determines dive duration (2)

Answer 3

• O2 supply: what’s available
• O2 demand: what’s consumed

Question 4

how do diving organisms change for diving

Answer 4

• integrated diving reflex

Question 5

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

Answer 5

• 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

Question 6

integrated diving reflex: diving bradycardia (2)

Answer 6

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

Question 7

what determines the magnitude of diving bradycardia (2)

Answer 7

• species
• anticipated dive duration

Question 8

integrated diving reflex: selective peripheral vasoconstriction (2)

Answer 8

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

Question 9

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

Answer 9

• brain
• retina
• lungs

Question 10

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

Answer 10

• extremities
• heart
• pancreas
• liver

Question 11

what happens to mean arterial pressure during diving

Answer 11

• remains relatively constant

Question 12

why do animals need to vasoconstrict during diving

Answer 12

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

Question 13

mean arterial pressure formula

Answer 13

• MAP = Q + TPR

Question 14

mean arterial pressure formula: Q (2)

Answer 14

• cardiac output
• defined by heart rate * stroke volume

Question 15

mean arterial pressure formula: TPR (2)

Answer 15

• total peripheral resistance
• resistance of all blood vessels in body

Question 16

can mammals and birds alter stroke volume

Answer 16

• they have limited capacity to alter stroke volume

Question 17

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

Answer 17

• 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)

Question 18

aerobic dive limit (2)

Answer 18

• 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

Question 19

which vertebrates tend to exceed aerobic dive limit

Answer 19

• some birds that exploit prey rich environments

Question 20

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

Answer 20

• decreases
• decreases
• increases
• decreases

Question 21

anaerobic dive: lactate (2)

Answer 21

• 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

Question 22

aerobic dive: lactate

Answer 22

• no lactate produce, so lactate pulse is not evident

Question 23

volume and pressure relationship

Answer 23

• volume is inversely proportional to pressure

Question 24

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

Answer 24

• volume of lungs decreases non-linearly

Question 25

PO2/PN2 and pressure relationship

Answer 25

• changes in PO2/PN2 in lungs are directly proportional to pressure

Question 26

what happens to PO2 of the lungs as pressure/depth increases

Answer 26

• PO2 of lungs increases linearly

Question 27

what happens to lung volume and total gas pressure (PO2, PN2) in SCUBA divers

Answer 27

• lung volume remains constant at different depths
• total gas pressure increases in proportion to depth

Question 28

what occurs to SCUBA diver during descent and what laws explain these changes (2)

Answer 28

• inhaled PO2 and PN2 increase and tissues will equilibrate to this
• Henry’s and Dalton’s laws

Question 29

what occurs to SCUBA divers during ascent (3)

Answer 29

• inhaled PO2 and PN2 decrease
• gases in tissues are supersaturated relative lungs
• excess nitrogen and oxygen leave blood and tissues

Question 30

excess O2 in body

Answer 30

• easily metabolized and does not pose as a problem

Question 31

excess N2 in body (2)

Answer 31

• not easily metabolized and must come out of body
• can serve as a problem

Question 32

what is the “bends”

Answer 32

• decompression sickness

Question 33

bends: when does it occur

Answer 33

• 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

Question 34

bends: symptoms (2)

Answer 34

• 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

Question 35

what do gas bubbles need to form (2)

Answer 35

• require a nucleus to come out of solution
• once formed, they can expand rapidly

Question 36

decompression chambers (2)

Answer 36

• 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

Question 37

where can bubbles formed from decompression be visualized in humans

Answer 37

• visible in tear fluid beneath contact lenses

Question 38

how does air and water act below dams/waterfalls (2)

Answer 38

• air bubbles are taken to depth and equilibrate at depth
• when water moves to surface, it is supersaturated with gases