What happens after the food gets broken down by pepsin in your stomach?
Once the food is broken down by pepsin in the stomach, it becomes a semi-liquid substance known as chyme. This partially digested food then passes through the pyloric valve and into the duodenum, which is the first part of the small intestine. Here are the key events that occur after food is broken down by pepsin in the stomach:
1. Neutralization of stomach acidity: As the chyme moves into the duodenum, the acidic environment coming from the stomach is gradually neutralized. The pancreas secretes bicarbonate ions (HCO3-), which help to raise the pH level and create a more alkaline environment suitable for the enzymes that function in the small intestine.
2. Secretion of pancreatic enzymes: The presence of chyme in the duodenum triggers the release of hormones such as cholecystokinin (CCK) and secretin from the intestinal cells. These hormones signal the pancreas to secrete pancreatic juices containing various digestive enzymes. The main pancreatic enzymes involved in the digestion of proteins, carbohydrates, and fats are:
- Trypsin and chymotrypsin: These enzymes further break down proteins into smaller peptides.
- Pancreatic amylase: This enzyme breaks down complex carbohydrates like starches into smaller sugars such as maltose and dextrin.
- Pancreatic lipase: This enzyme breaks down triglycerides (fats) into fatty acids and glycerol.
3. Emulsification of fats: The gallbladder releases bile, which helps to emulsify fats, making them more accessible for digestion. Bile contains bile salts that act as detergents, breaking down large fat droplets into smaller ones.
4. Digestion of carbohydrates and proteins: The pancreatic enzymes continue to break down carbohydrates, proteins, and fats into even smaller molecules, preparing them for absorption. Carbohydrates are broken down into simple sugars (glucose, fructose, and galactose), proteins are broken down into amino acids, and fats are broken down into fatty acids and glycerol. These smaller molecules are easier to absorb and transport across the intestinal wall.
5. Absorption of nutrients: The digested nutrients, including amino acids, simple sugars, and fatty acids, are then absorbed through the walls of the small intestine into the bloodstream. This process involves various transport mechanisms and requires the presence of specialized structures such as villi and microvilli in the intestinal lining.
6. Peristalsis and segmentation: The small intestine undergoes muscular contractions known as peristalsis and segmentation. These contractions help to mix the food with digestive enzymes, facilitate nutrient absorption, and move the remaining undigested material along the digestive tract.
After the absorption of nutrients, any undigested food components and water move into the large intestine (colon) for further processing, water absorption, and the formation of stool, which is eventually eliminated from the body through defecation.