Gas Exchange

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Gas Exchange

• Ana Zarate lt3

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6.4.1 Distinguish between ventilation, gas
exchange, and cell respiration

• Ventilation is the movement in and out of the
  lungs.
• Gas exchange is the diffusion of O2 across the
  surface of the alveoli and through the
  capillaries, then into the erythrocytes.
• Note that CO2 is mostly carried dissolved in the
  plasma itself and is moving out of the blood into
  the lungs at the same time O2 is diffusing the
  other way.
• Cell respiration is then individual cells
  metabolize macromolecules in the presence if O2,
  releasing CO2 in the process, The gases diffuse
  into and out if the cells and into or out of the
  mitochondria.

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6.4.2 Explain the need for a ventilation system

• A ventilation system is needed to maintain high
  concentration gradients in the alveoli

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6.4.3 Describe the features of alveoli that adapt
them to gas exchange

• Large total surface area
• Wall consisting of a single layer of flattened
  cells
• Film of moisture
• Dense layer of capillaries

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6.4.4 Draw and label a diagram of the ventilation
system including trachea, lungs, bronchi,
bronchioles, and alveoli
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6.4.5 Explain the mechanism of ventilation of the
lungs

• A mammal breathes by changing the air pressure
  within its lungs relative to the pressure of the
  outside atmosphere. During inhalation, the rib
  muscles and diaphragm contract. The volume of the
  thoracic cavity and lungs increases as the
  diaphragm moves down and the rib cage expands.
  Air pressure in the lungs falls below that of the
  atmosphere, and air rushes into the lungs.
  Exhalation occurs when the rib muscles and
  diaphragm relax, storing the thoracic cavity to
  its smaller volume. (Campbell book p. 891-
  diagram)

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Vocabulary

• Gas exchange
• Ventilation
• Cell Respiration
• Inhalation
• Exhalation
• Lungs
• Alveoli
• Capillaries
• Trachea
• Bronchi

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• Images from http//www.thehumanbody.ecsd.net/stud
  ent_gallery.htm