SCIENCEchapter2

• Movement of gases (diffusion) in the lungs

  1. Oxygen is inhaled

  2. Oxygen diffuses through alveolus wall into blood capillary

  3. Oxygen combines with hemoglobin to form oxyhemoglobin

  4. Oxygenated blood flows to body cells

  5. Oxyhemoglobin decomposes, releasing oxygen to body cells

  6. Carbon dioxide diffuses from body cells into blood, transported to lungs
• Diffusion


  The movement of molecules from an area of high concentration to an area of low concentration
• Alveolus


  The smallest unit or part of the lungs
• Oxyhemoglobin


  Hemoglobin combined with oxygen
• Oxygenated blood


  Blood containing oxyhemoglobin
• Cellular respiration


  The process where oxygen and glucose are used to produce energy
• Alveolus


  • Thin wall
  • Moist wall
  • Large surface area
  • Rich blood supply
• Oxygen diffuses from the alveolus into the blood capillary due to the difference in concentration
• Oxyhemoglobin is an unstable compound that can easily decompose to release oxygen
• Carbon dioxide diffuses from the body cells into the blood, and is then transported to the lungs
• The moist wall of the alveolus allows gases to dissolve and diffuse easily
• The thin wall of the alveolus and blood capillary facilitates efficient diffusion of gases
• The large surface area and rich blood supply of the alveoli enhance gas exchange
• Characteristics that make the process of diffusion easy and efficient

  • Thin wall of the alveoli
  • Moist wall of the alveoli
  • Large surface area of the alveoli
  • Network of blood capillaries
• Oxygen transport from alveoli to body cells

  1. Diffusion of oxygen from alveoli into blood capillaries

  2. Oxygen combines with hemoglobin to form oxyhemoglobin

  3. Oxyhemoglobin transports oxygen to body cells and releases it
• Diffusion happens due to the difference in concentration of oxygen and carbon dioxide between the alveoli and blood capillaries
• Oxygen concentration is higher in the alveoli compared to the blood capillaries, so oxygen diffuses from the alveoli into the blood capillaries
• Carbon dioxide concentration is higher in the blood capillaries compared to the alveoli, so carbon dioxide diffuses from the blood capillaries into the alveoli