Where does the absorption of nutrients starts and end?

The absorption of nutrients begins in the mouth and ends in the large intestine.

When you eat, your food is first broken down in your mouth by your saliva. The saliva contains enzymes that begin to break down the carbohydrates in your food. Once the food is broken down, it is then swallowed and enters the stomach.

The stomach is a muscular organ that churns the food and mixes it with gastric juices. The gastric juices contain hydrochloric acid and pepsin, which further break down the food. The food is then passed to the small intestine.

The small intestine is a long, coiled tube that is lined with villi. The villi are small, finger-like projections that increase the surface area of the small intestine. This increased surface area allows for more efficient absorption of nutrients. The nutrients are absorbed into the bloodstream through the villi.

Any undigested food that leaves the small intestine enters the large intestine. The large intestine is a shorter, wider tube that is lined with colonic crypts. The colonic crypts are small, gland-like structures that produce mucus. The mucus helps to lubricate the food and protect the colon from damage. The remaining water is absorbed from the food in the large intestine. The food is then expelled from the body as waste.