Why do the cells in the proximal tubule have microvilli?

Answer 1

They are folds in the plasma membranes and therefore increase the surface area available for absorption.

Answer 2

No following.

Absorption of nutrients.

Answer 3

They are there to increase the surface area of the small intestine.

Answer 4

To increase the rate of absorption.

Answer 5

Simply put, it allows absorption of nutrients and other food molecules to be carried out more efficiently than when there are no microvilli. Think of a single microvilli as a fisherman. It would not be wrong to say that the more fishermen there are, the more fish they'll catch, right? Also, please bear in mind that nutrients, etc. have been chemically broken down from their original structure, so it is likely that the molecules are spaced out, taking into account the effect of the body's temperature on the molecules. We may assume from here that the bonds of the chyme (digested food) keeping the nutrients together have been weakened or broken. The small intestine is approximately 1.5cm in diameter, so you can imagine that the cellulose/plant material or any other undigestable food being in the center of the small intestine and surrounded by nutrients and the like. (Picture description because I don't have one: Rectangle in a bigger rectangle. The first rectangle is the undigested food which we will surround with negative charges just to represent nutrients and other food molecules only! The second rectangle is the small intestine which will have spikes or folds on the inside of the rectangle which are the villi. Once you have imagined this, you should realize that when food is pushed through the small intestine, the folds/villi brush against it and pick up our charges on the outside of the food). If you find any contradicting information to what I have just said please tell me so I may edit this or remove it in the future.