Respiration

• Respiration


  The process of obtaining oxygen and delivering it to the cells for cellular respiration and removing carbon dioxide produced by cells
• Types of respiration


  • External respiration (Breathing)
  • Internal respiration (Cellular respiration)
• Types of internal respiration

  • Aerobic respiration
  • Anaerobic respiration
• External respiration (Breathing)


  The exchange of respiratory gases (oxygen and carbon dioxide) between the body and the environment
• Internal respiration (Cellular respiration)

  A metabolic process which occurs in cells, involves oxidation of organic molecules to produce energy (in the form of ATP)
• Aerobic respiration


  Requires oxygen, glucose is completely oxidised to produce 36-38 ATP and 2898 kJ energy
• Anaerobic respiration


  Without oxygen, glucose is not completely broken down, produces only 2 ATP and 150 kJ energy
• Anaerobic respiration in muscle cells

  Glucose molecules break down partially into lactic acid, causes muscular cramp and fatigue
• After vigorous activity


  Oxygen is used to oxidise accumulated lactic acid to form carbon dioxide and water
• Oxygen debt


  The amount of oxygen needed to remove lactic acid from muscle cells
• Anaerobic respiration in yeast


  Also known as fermentation, glucose is converted to ethanol and carbon dioxide
• Respiratory structures


  • Respiratory surface is moist, cells lining are thin, have large surface area
• Ventilation mechanism


  • Moves gases from respiratory medium to respiratory structures, increases rate of gaseous exchange, maintains high oxygen and low carbon dioxide levels
• Respiratory structures in humans

  • Nose/nasal cavity
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli
• Alveoli


  • Walls made of single cell layer, large number, secrete moisture, surrounded by blood capillaries, increased surface area for gas exchange
• Inhalation


  External intercostal muscles contract, internal intercostal muscles relax, rib cage moves up and out, diaphragm contracts and flattens, volume of thoracic cavity increases, air rushes in
• Exhalation


  External intercostal muscles relax, internal intercostal muscles contract, rib cage moves down and in, diaphragm relaxes, volume of thoracic cavity decreases, air is forced out
• Partial pressure differences


  O2 diffuses from alveoli to blood, CO2 diffuses from blood to alveoli
• During vigorous exercise


  Muscle cells require more O2 and glucose, rate and depth of breathing increases, heart rate increases to pump more blood
• Normal breathing rate is 15-20 times per minute, after vigorous exercise it increases to 30-35 times per minute
• In fear


  Breathing and heart rate increase to supply more oxygen and glucose for cellular respiration
• Adrenal glands secrete adrenaline, which increases heart rate and breathing rate
• Avoid living in polluted environments and do not smoke to maintain a healthy respiratory system
• Respiratory diseases


  • Asthma
  • Bronchitis
  • Emphysema
  • Pneumonia
  • Lung cancer