What happens when the juices from pancreas are mixed with chyme in upper part of small intestine?

The pancreas plays a vital role in the digestive process by producing and releasing digestive enzymes and bicarbonate ions into the upper part of the small intestine, specifically the duodenum. When these pancreatic juices mix with the chyme, a partially digested mixture of food coming from the stomach, several significant processes take place:

Neutralization of Stomach Acid: The chyme entering the duodenum is typically acidic due to the presence of hydrochloric acid from the stomach. The pancreatic juices contain bicarbonate ions (HCO3-) that help neutralize the acidic chyme, creating a more alkaline environment. This is essential for the optimal function of pancreatic enzymes and to protect the small intestine from the damaging effects of high acidity.

Digestion of Carbohydrates: The pancreas produces enzymes such as amylase that break down complex carbohydrates, such as starches and sugars, into simpler forms. Amylase breaks down starches into disaccharides, which can be further broken down by other enzymes.

Digestion of Proteins: Pancreatic enzymes, including proteases such as trypsin and chymotrypsin, break down proteins into smaller fragments, such as peptides and amino acids. These proteases are activated in the duodenum by another pancreatic enzyme called enterokinase.

Digestion of Lipids (Fats): The pancreas releases lipase, an enzyme that breaks down triglycerides (fats) into smaller molecules called fatty acids and glycerol. Lipase requires the presence of bile salts from the liver to function effectively. Bile salts help emulsification fat globules, increasing the surface area and facilitating lipase's action.

Absorption of Nutrients: The products of digestion, including simple sugars, amino acids, and fatty acids, are absorbed through the walls of the small intestine into the bloodstream. The specialized structure of the small intestine, with its villi and microvilli, increases the surface area for efficient absorption.

Therefore, when the juices from the pancreas mix with chyme in the upper part of the small intestine, they contribute to the neutralization of stomach acid, the digestion of carbohydrates, proteins, and fats, and the subsequent absorption of nutrients into the body.