How are alveoli adapted for their function?

Answer 1

The site of gaseous exchange in mammals is the epithelium of the alveoli. To enable efficient gaseous exchange the alveoli have a number of adaptations to make them fit for purpose. Since gaseous exchange in mammals is reliant on diffusion and diffusion is proportional to:

Surface area x difference in concentration

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Length of diffusion path

The alveoli are adapted for gas exchange in three main ways:

1) A thin exchange surface- the alveolar epithelium and the endothelium of the capillaries which surround the alveoli are only one cell thick each which means there is a very short diffusion pathway which allows for a fast rate of diffusion. The diffusion pathway is shortened further as the distance between the alveolar air and red blood cells is reduced as the red blood cells are flattened against the capillary walls. The alveolar epithelium is also partially permeable which allows specific substances to diffused through easily.

2) The alveoli are covered in a series of blood vessels and capillaries which mean that the gasses can diffuse directly into the bloodstream. The action of the heart constantly circulated the blood through the capillaries surrounding the alveoli in the lungs and this blood Flow through the capillaries maintains a steep concentration gradient. Once oxygen has diffused into the blood, it is removed from the site of diffusion by the constant blood flow and replaced with de-oxygenated blood flowing through. Red Blood cells are also slowed as they flow through the capillaries, this allows more time for the gases to diffuse across the alveolar epithelium and the endothelium of the capillaries.

3) There are about 300 million alveoli is each human lung, their total surface area is about 70m�² (about half the size of a tennis court) a large surface area, means that the gas exchange is more efficient as there is more opportunity for diffusion to take place. and increase the space in lungs

Answer 2

Probaly something to do with their shape. It can soak up all the things easily...If it soaks up things...:I

yeh, they are adapted to a certain shape (which looks like a bunch of circles) and this gives them a bigger surface area so that they can absorb more carbon dioxide and give out more oxygen to the blood

Answer 3

Alveoli are very thin and made up of single layer of the flat cells. You have thin walled capillaries, which cover the alveoli. Oxygen and carbon bi oxide pass easily through this thin layers.

Answer 4

adapted by big surface area

so it can absorb more oxygen and contains lots of oxygen

very thin tubes for diffusion

Answer 5

Alveoli are adapted for absorbing gases as they have a moist surface and gases diffuse better through moist surfaces

Answer 6

branches are adapeted