Where do nutrients get digested in the digestive system?

The digestion of nutrients occurs at different stages and different parts of the digestive system. Here is a breakdown of where the major nutrients are primarily digested:

1. Carbohydrates:

- Mouth: The digestion of carbohydrates begins in the mouth with the enzyme salivary amylase, which starts breaking down starches into simple sugars.

- Small intestine: The majority of carbohydrate digestion occurs in the small intestine. The pancreas releases enzymes such as pancreatic amylase, maltase, sucrase, and lactase, which further break down complex carbohydrates into simple sugars like glucose, fructose, and galactose. These sugars are then absorbed into the bloodstream through the intestinal walls.

2. Proteins:

- Stomach: Protein digestion begins in the stomach with the enzyme pepsin, which is activated by the acidic environment. Pepsin breaks down proteins into smaller peptide fragments.

- Small intestine: Further protein digestion occurs in the small intestine. The pancreas releases enzymes such as trypsin, chymotrypsin, and carboxypeptidases, which continue breaking down peptides into individual amino acids. These amino acids are then absorbed into the bloodstream through the intestinal walls.

3. Fats:

- Mouth: Lingual lipase, an enzyme present in the saliva, begins the initial breakdown of fats, but the majority of fat digestion occurs in the small intestine.

- Small intestine: The pancreas releases enzymes called lipases, which break down triglycerides (the main form of fat in food) into fatty acids and glycerol. Bile, produced by the liver and stored in the gallbladder, helps emulsify fats, making them easier to be broken down by lipases. The resulting fatty acids and glycerol are absorbed into the lymphatic system and eventually enter the bloodstream.

4. Nucleic acids (DNA and RNA):

- Small intestine: Nucleases, enzymes produced by the pancreas and intestinal cells, break down nucleic acids into nucleotides. Nucleotides are then further broken down into individual nitrogenous bases, sugars, and phosphate molecules, which are absorbed into the bloodstream.

It's worth noting that the digestive system also plays a role in the absorption of vitamins, minerals, and water. The small intestine is the primary site where most nutrients are absorbed, facilitated by various transport mechanisms and specialized structures like villi and microvilli.