BLOOD GAS TRANSPORT PART 2

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• BLOOD GAS TRANSPORTPART 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 divers 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 animals blood
• Bubble formation is not a problem when the animal
  returns to the surface

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ENDBLOOD GAS TRANSPORTPART 2