The process responsible for the movement of oxygen and carbon dioxide between blood and capillary beds is:?

Question

A) osmosis

B) active transport

C) filtration

D) diffusion

Answer 1

It's D diffusion.  The first answer is correct.  Don't let others convince you otherwise.

Both carbon dioxide (CO2) and molecular oxygen (O2) are non-polar molecules meaning they are hydrophobic.  Therefore, they can cross the aveolar membranes into the capillary readily without the help of ion channels (facilitated diffusion) or a pump that requires ATP (active transport).  All it needs is a concentration gradient.  Since there is more oxygen in the aveoli than in the capillary, the oxygen will unload and go toward the capillary.  On the other hand, there is more CO2 concentration (waste product of cellular respiration) in the capillary (blood), the CO2 moves from high concentration (blood) to low concentration (aveloi).

Osmosis is specifically the movement of WATER from high water concentration (low solutes) to low water concentration (high solutes).  NOT A for sure.  We're not talking about water at all.

Answer 2

D - Diffusion

A) - Osmosis is water pressure related, its more related to plants.

B) - Active transport is how ions and certain molecules are picked from the vascular system against their concentration gradient, but it would expend way too much energy to actively transport oxygen and CO2 against the conc. gradients.

C) - Filtration is how the glomerulus of the kidneys works.

Answer 3

I believe the answer is A.

Osmotic pressure and blood pressure are the two dominant pressures in capillary beds. Capillary beds contain albumin, a chemical that contributes to osmotic pressure. Because the osmotic pressure is so high in the capillary bed, and the blood pressure is so low, the O2 and CO2 squeeze out the walls of the capillaries, leaving deoxygenated blood to circulate throughout the venous bloodstream.

That is what I remember from Anatomy and Physiology, I wouldn't take my answer for granted though. Or anyone else's!