ILO 1: state the adaptaions of alveoli for gas exchange

list 3 risk factors required to make an exchange site effiecent

1- large surface area for exchange

2- short diffusion distance

3- high concentration gradient

explain what is meant by the term ‘concentration gradient’

difference in concentration of a substance between two areas

explain the term ‘diffusion’

passive transport mechanism that moves particles from an area of high concentration to an area of low concentration

• 2 types:

• - simple

• - facilitated

what is the importance of a concentration such as simple diffusion

direction - high to low concentration

rate- steeper gradient , faster rate

energy - provides potential energy

how are aveoli adapted to a large surface area

lots of alveoli for a large surface area

how are aveoli adapted to a short diffusion distance

thin layer of cell to make diffusion quicker

how are aveoli adapted to a high concentration gradient

Continuous ventilation and blood flow constantly refresh the air and blood supply, maintaining the steep concentration gradient for rapid gas diffusion.