Download Adv Phys gas transport part 2

BLOOD GAS
TRANSPORT
PART 2
Instructor Terry Wiseth
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PHYSIOLOGY OF
DIVING
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PHYSIOLOGY OF DIVING
Aquatic mammals can spend up to 10
minutes under water without breathing
ex: whales, seals, dolpins etc
Trained free divers (human) can spend a
minute or more under water without
breathing
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PHYSIOLOGY OF DIVING
Needs of O2 for metabolism is provided by:
O2 stored in lungs
O2 bound to Hb
Myoglobin
Dissolved O2 in body fluids
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PHYSIOLOGY OF DIVING
Largest physiological problem in diving is
maintaining heart and brain function
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PHYSIOLOGY OF DIVING
Diving reflex
Cardiovascular response to immersion
of the head in water
Slowing of the heart rate by several
beats per minute
More profound if the water is cold
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PHYSIOLOGY OF DIVING
Combines with peripheral
vasoconstriction and reduced metabolism
induced by hypothermia
Increases the chances of survival for
drowning victims in cold water
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PHYSIOLOGY OF DIVING
Aquatic animals
Reflexive bradycardia and peripheral
vasoconstriction
Effect is to force skeletal muscle to
draw on its store of O2 in myoglobin and
then shift to anaerobic glycolysis
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PHYSIOLOGY OF DIVING
Various marine mammals have been
found to have adapted special abilities
which help in their respiratory processes,
enabling them to remain down at great
depths for long periods of time
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PHYSIOLOGY OF DIVING
The Weddell seal only stores 5% of its
oxygen in its lungs, and keeps the
remaining 70% of its oxygen circulating
throughout the blood stream
Humans are only able to keep a small 51%
of their oxygen circulating throughout the
blood stream, while 36% of the oxygen is
stored in the lungs
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PHYSIOLOGY OF DIVING
The explanation for this is that the
Weddell seal has approximately twice the
volume of blood per kilogram as humans
As well, the Weddell seal's spleen has the
ability to store up to 24L of blood
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PHYSIOLOGY OF DIVING
It is believed that when the seal dives the
spleen contracts causing the stored
oxygen enriched blood to enter the blood
stream
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PHYSIOLOGY OF DIVING
Also, these seals have a higher
concentration of a certain protein found
within the muscles known as myoglobin,
which stores oxygen
The Weddell seal contains 25% of its
oxygen in the muscles, while humans only
keep about 12% of their oxygen within the
muscles
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PHYSIOLOGY OF DIVING
Not only does the Weddell seal store
oxygen for long dives, but they consume it
wisely as well
A diving reflex slows the pulse, and an
overall reduction in oxygen consumption
occurs due to this reduced heart rate
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PHYSIOLOGY OF DIVING
Regulatory mechanisms reroute blood to
where it is needed most (brain, spinal
cord, eyes, adrenal glands, and in some
cases placenta) by constricting blood
flow where it is not needed (mainly in the
digestive system)
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PHYSIOLOGY OF DIVING
Blood flow is restricted to muscles during
long dives and they rely on oxygen stored
in their myoglobin and make their ATP
from fermentation rather then from
respiration
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PHYSIOLOGY OF DIVING
scuba divers
If working at depths greater than 30
meters a diver breathes air at higher
than atmospheric pressure and can
accumulate dissolved gases in blood
and tissues
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PHYSIOLOGY OF DIVING
If diver’s return to the surface is too rapid
the dissolved gas comes out of solution
forming bubbles in tissues and blood
vessels (mainly N2) “bends”
Condition is prevented by controlled
decompression
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SCUBA DIVER
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PHYSIOLOGY OF DIVING
Diving animals exhale at the start of a
dive
Increased pressure of diving to
considerable depths decreases the
volumes of gases in the lungs to the point
of causing the lungs to collapse
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PHYSIOLOGY OF DIVING
Reduced air volume in lungs where gases
are exposed to capillaries minimizes the
transfer of dissolved N2 to the animal’s
blood
Bubble formation is not a problem when
the animal returns to the surface
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END
BLOOD GAS TRANSPORT
PART 2
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