BIOLOGY: respiration

• 2 limitations of bell jar model:

  1. Wall of bell jar doesn’t contract/expand (intercostal muscles)
  2. rubber sheet isn’t curved when relaxed (diaphragm)
• Inspiration:

  lungs inflate, diaphragm contracts + falls flat, intercostal muscles expand, volume in thoracic cavity increases, pressure decreases.
• Expiration:

  lungs deflate, diaphragm relaxes + curves, intercostal muscles relax, volume in thoracic cavity decreases, pressure increases.
• Alveoli- gas exchange:

  alveoli are adapted by a good blood supply, a large surface area, thin walls and moist lining
• Alveoli:

  CO2 goes through and into the alveoli

  O2 goes through the and out of the alveoli, entering the blood stream.
• Alveoli:

  tar in smoking destroys the alveoli- causing the surface area to reduce, leads to emphysema.
• Cilia and smoking:

  • cilia + mucus make up the cleaning mechanism

  • cilia waft up the mucus for it to either be coughed or swallowed

  • tobacco paralyses the cilia

  • tobacco causes the mucus to thicken, making it difficult to move out
• • aerobic respiration = glucose + oxygen -> carbon dioxide + water (ATP)
• Anaerobic respiration = glucose -> lactic acid (ATP)
• Aerobic respiration is more efficient than anaerobic because it produces more ATP per molecule of glucose.