sub deck: breathing and respiration

• Respiratory system function


  Gas exchange - oxygen enters the blood and carbon dioxide is removed
• Breathing


  Allows gases into and out of the respiratory system
• Breathing in


  1. Intercostal muscles contract raising ribs up and out

  2. Diaphragm contracts and flattens

  3. Increase in thoracic cavity volume

  4. Air moves in
• Breathing out


  1. Intercostal muscles relax, ribs move down and in

  2. Diaphragm relaxes and moves back to dome shape

  3. Decrease in thoracic cavity volume

  4. Air moves out
• Purpose of breathing


  For the chemical reaction called aerobic respiration - uses oxygen and releases energy
• Aerobic respiration


  Happens inside mitochondria in cells
• Aerobic respiration


  Glucose + oxygen
• Glucose


  Comes from the carbohydrate we eat
• Oxygen


  Comes from the air we breathe
• Water


  Can remain in cells or may be lost in urine/faeces or breathing out
• Carbon dioxide


  Acidic gas that needs to be breathed out to avoid damaging cells
• During exercise


  We breathe faster and deeper so muscles get enough oxygen for aerobic respiration and carbon dioxide can be removed
• Anaerobic respiration in muscle

  Glucose
• Lactic acid


  Can cause muscle pain and fatigue
• After vigorous exercise


  Insufficient oxygen causes anaerobic respiration and lactic acid buildup
• Breaking down lactic acid after exercise


  Lactic acid is broken down into carbon dioxide and water using oxygen
• Oxygen debt


  The quantity of oxygen needed to break down the lactic acid
• Anaerobic respiration in other organisms

  Yeast respires anaerobically to produce carbon dioxide and ethanol - this is fermentation and how we make alcohol
• Bread making


  1. Starch in flour is digested into glucose by yeast enzymes

  2. Glucose is used for respiration
• Respiratory system's adaptations against infection

  • Prevent microorganisms from entering the lungs
  • Expel mucus and particles from the lungs
• Mechanism to prevent infection in the respiratory system

  1. Air enters the trachea

  2. Branches into smaller tubes

  3. Mucus produced by goblet cells traps particles

  4. Cilia move the mucus up and out of the lungs

  5. Coughing expels large objects
• Despite adaptations, we all suffer from infections of the respiratory system from time to time
• Laryngitis


  Inflammation of the larynx or voice box
• Tracheitis


  Inflammation of the trachea
• Bronchitis


  Inflammation of the bronchial tubes
• Infections of the respiratory system are associated with increased mucus production and coughing
• Pleural membranes


  • Line the chest cavity
  • Cover the lungs
  • Fluid between acts as a lubricant
• Cilia


  Hair-like projections that move mucus up and out of the lungs
• Smokers have difficulty clearing mucus when cilia are affected as they become wilted and are not able to move mucus up and out of the lungs causing the airways to become blocked up with mucus making it hard for the smoker to breathe
• Emphysema


  Disease where alveoli walls break down, reducing lung surface area
• Reduced lung surface area in emphysema

  Decreases the amount of oxygen that can enter the blood
• why do you cough when you have a chest infection

  the airways of the lungs well and produce mucus