REGULATION OF RESPIRATION

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REGULATION OF RESPIRATION
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outline
Theory Preparations before operation Operation
in neck Item
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? Theory

• The activity of the respiratory centers
  regulate the movement of respiration. The
  respiratory centre activity in turn is influenced
  by afferent impulses from the lungs and various
  other parts of the body.
• Factors which modify respiration are nervous
  factors and chemical factors (CO2 and O2
  tensions or H in blood or cerebrospinal fluid).
• There are many methods of recording
  respiratory movement directly recording the
  change in airway pressure and electricity in
  diaphragm. In this experiment we adopt the
  methods of recording diaphragm movement.

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? Theory

• To observe the effects of some factors on
  respiration and grasp the recording technical of
  respiration movement.

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? APPARATUS AGENTS

• APPARATUS
• a. Mammal animal operating apparatus
• b. Tracheal cannula
• c. Syringe(30ml and 50ml respective)
• d. A rubble tube 50cm in length
• e. A bladder of ball filled with CO2
• f. Protective electrode
• g. Power Lab System
• AGENTS
• a. 20 urethane
• b. 0.9 saline solution
• c. 3 lactic acid

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? Preparations before operation

• 1 Anesthesia 20 urethane (5mg/kg) is
  administered through the marginal vein in the
  ear.
• The position where we begin to inject
  anesthetic should be near to distal of marginal
  ear as possible as we can.
• The velocity of injection should be slow and
  we should monitor the respiration of the animal.

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? Preparations before operation

• 2 Fixing After anesthesia, the rabbit is fixed.
• We should lay the rabbit on its back on the
  operation table, then fix the limbs with the help
  of the ropes.

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? Preparations before operation

• 3 Shearing Before the operation, the hair of the
  operation site should be sheared.
• This step we should avoid injuring the
  animals skin.

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? Operation in neck

• 1 Slice the skin With the scissors make a mid
  incision 3-4 centimeters in length through the
  skin over the region from the lower jaw to the
  breastbone. The anterior chest is now exposed.

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? Operation in neck

• 2 Separate the subcutaneous tissue and muscle to
  expose the trachea
• In this step, we should avoid injuring the
  blood and nerve.

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? Operation in neck

• 3 Endotracheal intubation
• Separate the trachea from other tissues,
  pass a thread under it, make a ?shape incision
  on the trachea 2-3 cm under the throat, then
  insert the tracheal cannula toward the lung and
  tie the cannula and the trachea together.

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? Operation in neck

• 4 Separate the vagus nerve
• Identify carefully the three nerves located
  in carotid sheath vagus nerve is the thickest,
  depressor nerve is the thinnest and the
  sympathetic nerve is moderate. Isolate them by
  glass dissecting needle and pass various color
  threads separately under them for preparation.

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? Operation in neck

• The operating action of isolating blood vessels
  and nerves should be gentle by using glass
  dissecting needle. The isolating sequence is from
  thin to thick.

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?Separate the xiphoid process

• 1 Make a skin incision located in xiphisternum
  2-3cm in length.
• 2 Open the abdominal cavity along the linea alba
  abdominis 2-3cm in length.
• 3 Separate the muscles in the middle of the belly
  to expose and isolate the xiphoid process.

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?Separate the xiphoid process

• 4 The peritoneum around the xiphoid process was
  sheared carefully. Lift the xiphoid process, you
  can see two slips of diaphragm adhering to the
  xiphoid process.
• 5 Cut between the body of sternum and the
  xiphoid process.

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?Separate the xiphoid process

• 6 Connect the xiphoid process with the computer
  through a pressure transducer.

Do not injury the diaphragm and avoid
pneumothorax.
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? Item

• (1) Observe the normal respiration movement.
• (2) Increase the concentration of CO2 during
  inspirationa ball filled with CO2 is joined with
  one side of trachea cannula, increasing the
  concentration of CO2 during inspiration via
  opening the clip of the bladder. When the obvious
  change of respiratory movement happened,close the
  clip instantly.

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? Item

• (3) Observe the change of respiration movement
  when decrease the concentration of O2 during
  inspiration close one side of the trachea
  cannula with a bladder filled with atmosphere
  through a bottle full of sodium-lime and have the
  animal breath in this bladder, then wait for a
  moment. The amount of carbon dioxide dose not
  change (because the sodium-lime absorbed the
  carbon dioxide during expiration)

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? Item

• (4) Observe the change of respiration movement
  when enlarge the dead space close one side of
  trachea cannula. Then wait for a moment, the
  other side of trachea cannula is connected with a
  rubber tube about 50 cm in length. The animal
  respire through the rubber tube.
• (5) Observe the change of respiration movement
  when increase the H concentration in blood
  about 1-2ml 3 lactic acid is intravenously
  injected rapidly.

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? Item

• (6) Observe the change of respiration movement
  when pour gas in pulmonary
• when the respiration is stable,the pulmonary
  is poured into 20 ml atmosphere via a 30ml
  syringe connected with one side of trachea at the
  end of inspiration. At the same time, the other
  side of treacha is blocked.
• (7) Observe the change of respiration movement
  when cut vagus nerves. One side of vagus nerves
  or both side of that was cut.

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? Precautions

• 1.We should keep the trachea clear to move blood
  blockage out.
• 2.Make an mid line incision to isolate
  xiphisternum for fear that blood too much.
• 3.Pay attention not to injury diaphragm to avoid
  pneumothorax.
• 4.Insert the electrode into diaphragm
  appropriately .
• 5.Dcreasing the CO2 concentration during
  inspiration should be slow.
• 6.The dose of 3 lactic acid should not too much.

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? Question

• 1.What is the difference of mechanism that
  enhancing respiratory movement by increasing CO2
  concentration during inspiration or decrease the
  concentration of O2 during inspiration or
  increase the H concentration in blood?
• 2.What is the role that vagus play in rhythmic
  respiration movement?