Biology Chapter 4
- Created by: elliebaxter
- Created on: 23-01-17 16:16
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- 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
- Uses positive pressure
- Reasons why people can't breathe
- 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
- Energy released is used to...
- Breathing and gas exchange
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