how does surface area play a role in the functioning of the lungs?

Answer 1

Your body needs massive amounts of Oxygen to function (to remove carbon dioxide, power reactions, etc). Each red blood cell in your body contains haemoglobin molecules which bind oxygen for transport. Now the interesting thing is that each haemoglobin can bind 4 molecules of oxygen and each blood cell has approximately 250,000 molecules of haemoglobin in it, so each blood cell carries in excess of 1 million oxyen molecules. Now, with a few million red blood cells running through the lungs, you'd think thats enough, but its not, your body needs a lot more, but your lungs are quite small (the primary working portion of the lung itself actually starts (approximately) just above your nipple).

So, to pick up the slack, the lungs are composed of alveoli, or air sacs, which are only 1 cell thick, allowing loads of them to fit into a compact area. With so many of these alveoli surfaces to interact with the blood cells, there is enough 'surface area' to ensure enough oxygen is supplied at an adequate speed for powering reactions and removing (exchanging) carbon dioxide (the waste product from many reactions).

Interesting note - If you were able to disect your lungs and lay them flat, they would cover the equivalent area of a tennis court.

Answer 2

As it is the interface of blood gas transfer, it is very important. In lung diseases it is reduced, anatomically and functionally , resulting in poor oxygenation of the blood.

Imagine lung as a filter which acts as a medium to transfer the gases - Driving C02 out and absorbing O2 in .

If for any reason, the filter is damaged in area, that area cant transfer the gases. Even if the area is not lost but if loses the function of filtering it is a loss of filter, isnt it - same with lungs

Answer 3

Because the rate of gases diffusion (O2, CO2) across the cell membranes (lung cells) depend on the surface area.

If you increase the surface area, then you'll get faster rate of diffusion of gases (O2, CO2) across the cell membranes (of lungs' cells).

extra: The diffusion rate also depend on distance, concentration gradients, not just surface area.

Answer 4

more surface area means that more O2 can get to more blood cells at one time