Biology Chapter 4

?
View mindmap
  • Biology Chapter 4 - Part 1
    • Breathing and gas exchange
      • Lungs are situated in the thorax inside the ribcage and above the diaphragm
      • Breathing in - 1 - intercostal muscles between the ribs contract moving t6he ribcage up and down 2 - diaphragm flattens 3 - volume of thorax increases 4 - pressure in thorax decreases and air drawn in
      • Breathing out - 1 - diaphragm and intercostal muscles relax 2 - ribcage moves up and down and diaphragm becomes dome shaped 3 - volume of thorax decreases so air forced out
    • Adaptations of aveoli
      • O2 absorbed a CO2 is removed
      • Large surface area, thin walls and short diffusion path for efficient transport system
      • Surface area of lungs increased by aveoli
      • Alveoli have thin walls, large surface area and good blood supply
      • Lungs are ventilated to maintain steep diffusion gradient
      • O2 diffuses into many capillaries surrounding the alveoli and CO2 diffuses back out
    • Artificial breathing aids
      • Reasons why people can't breathe
        • If the alveoli are damaged the surface area for gas exchange is reduced
        • If the tubes to the lungs are narrowed, less air can be moved through them
        • If the person is paralysed, their muscles cannot pull the rib cage up and down
      • The iron lung - used for paralysed people, they lay in a large metal cylinder and a vacuum was forned and created a negative pressure
        • As air is drawn out, person breathes in
      • Bags of air linked to masks that force air down the trachea
        • Uses positive pressure
          • Often smaller, easier to manage in the home
    • Aerobic respiration
      • Energy released is used to...
        • build larger molecules from smaller ones
        • move muscles
        • maintain a constant body temperature
        • move materials ie. mineral ions, against the conc. gradient (active transport)
        • builds sugars + nitrates into amino acids and then proteins in plants
        • Digestion
        • Synthesis proceses
      • Takes place in the mitochondria

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Respiration and exercise resources »