Thorax -> Upper part of the body
Diaphragm seperates the THORAX from the lower part.
Air comes in through the Trachea, and then into the bronchi, which seperates into two tubes, each called the bronchus. One bronchus goes into one lung each, where it seperates into little bronchioles. They have alveoli on the end of them. Which are little air sacs where gaseous exchange takes place.
- Intercostal muscles and diaphragm contract
- Thorax volume increases
- Pressure is increased and air is breathed in
- Intercostal muscles and diaphragm relax
- Thorax volume decreases
- Air is forced out
DIFFUSION THROUGH CELL MEMBRANES
Alveoli and Villi
ALVEOLI is where gas exchange takes place in the lungs.
It transports oxygen into the bloodstream and removes waste carbon dioxide.
It is specialised so the diffusion rate is quicker:
- Thin Walls
- Massive Surface Area
- Good Blood Supply
VILLIincreases the surface area in the small intestine.
This transports the digested food quicker.