Ch. 7 - The Breathing System

• What takes place when we breathe

  1. Air fills our lungs

  2. Oxygen from the air passes from our lungs into our bloodstream

  3. Red blood cells carry oxygen to all the cells of our body

  4. Oxygen is used to release energy from food

  5. Carbon dioxide and water vapour are produced by respiration in each body cell. They enter the bloodstream & are carried in the plasma to the lungs.

  6. Carbon dioxide and water vapour pass from the blood into the lungs and are then breathed out
• Respiration

  The release of energy from food
• The breathing system supplies oxygen for respiration and gets rid of the waste products of respiration (i.e. carbon dioxide and water)
• Excretion is..

  getting rid of the waste products of reactions from the body

  • carbon dioxide and water vapour are excreted by the breathing system
  • The breathing system is also called the respiratory system
• Parts of the Breathing System

  • Nose
  • Bronchi & bronchioles
  • Diaphragm
  • Trachea
  • Alveoli
  • Ribs & intercostal muscles
• Nose Functions

  We are supposed to inhale through our nose. The reasons for doing this are:

  • Hairs and mucus trap dirt particles and bacteria in the nose
  • Air is warmed and moistened as it passes through the nose. Warm and moist air helps oxygen to pass from the lungs into the bloodstream more easily
• Trachea Functions

  • The trachea, or windpipe, carries air to and from the lungs
  • It is made of C-shaped rings of rigid cartilage (to prevent it from collapsing)
• Bronchus & Bronchioles

  • We have 2 bronchi
  • each bronchus carries air between the trachea and a lung
  • The two bronchi subdivide many times to form tiny tubes called bronchioles
  • Bronchioles carry air to and from the air-sacs, or alveoli.
• Alveolus

  • each lung contains millions of tiny air-sacs called alveoli
  • The function of each alveolus is gas exchange:

  1. Oxygen passes from the air in the alveolus into the blood vessels
  2. At the same time, carbon dioxide and water pass from the blood vessels into each alveolus
  3. The gases pass in each direction by a process called diffusion. As an adaptation for diffusion each alveolus has a very thin lining, is moist and is surrounded by many tiny blood vessels called capillaries
• Diaphragm

  • The diaphragm is a sheet of muscle that forms the base of the chest
  • Along with the ribs and intercostal muscles (located between the ribs), the diaphragm causes air to move into or out of the lungs
• The Difference between Air Breathed in and Air Breathed out