Day 2 Notes

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The Respiratory System

• Day 2 Notes Process of Breathing

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Inhalation vs. Exhalation
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Muscles of the Respiratory System

• Diaphragm dome-shaped muscle separating thoracic
  and abdominal cavities
• External intercostals pulls ribs to elevate rib
  cage inspiratory muscles
• Internal intercostals depresses rib cage

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• Inspiration

• Expiration

• Inspiratory muscles relax
• Internal intercostals depress ribcage
• Rib cage descends, lungs recoil
• Volume in thoracic cavity decreases.
• Pressure in thoracic cavity increases
• Gases forced out

• Diaphragm contracts flattens
• External intercostals lifts rib cage
• Lungs stretched to larger size
• Volume in thoracic cavity increases
• Air pressure inside lungs decrease
• Air sucked into lungs

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Air Content
Inspiration Content Exhalation
21 Oxygen 17
0.04 Carbon Dioxide 4.04
78 Nitrogen 78
0.96 Inert Gases 0.96
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• Vital Capacity (VC) total exchangeable air
• VC TV IRV ERV
• Tidal Volume (TV) amount of air in/out during
  normal, relaxed breathing (500ml)
• Inspiratory Reserve Volume (IRV) additional air
  that can be forcibly inhaled breathing in a
  normal tidal volume (3100)
• Expiratory Reserve Volume (ERV) additional air
  that can be forcibly exhaled after the expiration
  of a normal tidal volume(1200)
• Residual Volume (RV) air still left in lungs
  (1200)
• allows gas exchange to continue between breaths

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Respiratory capacity

• Factors that affect capacity size, age, sex,
  physical condition

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spirometer

• Used to measure respiratory capacities

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Gas transport in blood

• Oxygen attaches to hemoglobin molecules inside
  RBCs
• Hemoglobin respiratory pigment, contains 4 heme
  groups with iron (Fe)

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Gas transport in blood

• Carbon dioxide
• Transported as bicarbonate ions (70)
• Bound to hemoglobin (23)
• Dissolved in plasma (7)

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Controlling Respiration

• Control center medulla oblongata
• Responds to pH changes in blood
• High CO2 ? carbonic acid forms ? lowers pH
• O2 sensors in the aorta and carotid arteries

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External Respiration

• Ventilation
• exchange of air between lungs and atmosphere
• Physical process during which oxygen is taken up
  by capillaries of lung alveoli and carbon dioxide
  is released from blood.
• Gas Exchange in pulmonary capillaries
• Breathing is largely aninvoluntary activity

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Internal Respiration

• Tissue respiration/cellular respiration
• Refers to a metabolic process in which oxygen is
  released to tissues or living cells and carbon
  dioxide is absorbed by the blood.
• Once inside the cell the oxygen is used for
  producingenergy in the form of ATP
• All cells require oxygen for metabolism
• All cells require means to remove carbon dioxide
• Gas exchange at cellular level