1.6.9

Structure & Function of the Gas Exchange System

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Structure and Function of the Gas Exchange System

The gas exchange system in humans is about the inhaling of oxygen and the exhaling of carbon dioxide.

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Respiration

  • Aerobic respiration is a chemical reaction.
    • Respiration converts glucose and oxygen into carbon dioxide and water.
  • Respiration is different from breathing.
    • Breathing is the inhaling of oxygen and the exhaling of carbon dioxide.
    • Respiration occurs in organelles called mitochondria.
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The gas exchange system

  • Air is inhaled through the mouth.
  • Air enters the trachea.
    • The trachea is also called the windpipe.
  • The trachea splits into two bronchi.
    • The left bronchus goes into the left lung.
    • The right bronchus goes into the right lung.
  • In each lung, the bronchus splits into over 30000 bronchioles.
    • Alveoli are at the tips of the bronchioles.
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Alveoli

  • Alveoli are air sacs in the lungs
    • Alveoli are where the gas exchange takes place.
  • Oxygen enters the blood at the alveoli.
    • Oxygen flows from the alveoli to the heart.
    • The heart pumps blood with oxygen in it around the body.
  • Carbon dioxide leaves the blood through the alveoli.
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Alveoli walls

  • To maximise the gas exchange, alveoli have very thin walls.
    • Alveoli walls are only one cell thick.
    • The thin alveoli walls allow more efficient diffusion of oxygen and carbon dioxide.
  • Alveoli walls are moist and permeable
    • Gases can dissolve and pass through the Alveoli.
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The diaphragm

  • The diaphragm is an important muscle for breathing.
  • When you inhale, the diaphragm contracts.
    • The contracted diaphragm creates more volume within the ribcage.
    • The increased volume allows more air into the lungs.
  • When you exhale, the diaphragm relaxes.
    • The relaxed diaphragm reduces the volume within the ribcage.
    • As the ribcage volume decreases, air is pushed out of the lungs.

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1Biology

1.1Cells, Tissues & Organs

1.2Reproduction & Variation

1.3Ecological Relationships & Classification

1.4Digestion & Nutrition

1.5Plants & Photosynthesis

1.6Biological Systems & Processes

2Chemistry

2.1Particles

2.2Chemical Reactions

2.3Atoms, Elements, Compounds

2.4The Periodic Table

2.5Materials & the Earth

2.6Reactivity

2.7Energetics

2.8Properties of Materials

3Physics

3.1Energy

3.2Forces & Motion

3.3Waves

3.4Electricity & Magnetism

3.5Matter

3.6Space Physics

4Thinking Scientifically

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