Question

Ptyalin enzyme is secreted by
salivary glands (b) pancreas (c) gall bladder (d) stomach​

Answer 1

Answer:

ptyalin is secreted by salivary glands

Answer 2

Answer:Digestion: stomach

In the stomach, food undergoes chemical and mechanical digestion. Here, peristaltic contractions (mechanical digestion) churn the bolus, which mixes with strong digestive juices that the stomach lining cells secrete (chemical digestion). The stomach walls contain three layers of smooth muscle arranged in longitudinal, circular, and oblique (diagonal) rows. These muscles allow the stomach to squeeze and churn the food during mechanical digestion.

Powerful hydrochloric acid in the stomach helps break down the bolus into a liquid called chyme. A thick mucus layer that lines the stomach walls prevents the stomach from digesting itself. When mucus is limited, an ulcer (erosion of tissue) may form.

Food is digested in the stomach for several hours. During this time, a stomach enzyme called pepsin breaks down most of the protein in the food. Next, the chyme is slowly transported from the pylorus (end portion of the stomach) through a sphincter and into the small intestine where further digestion and nutrient absorption occurs.

Bile liquid is created in the liver and stored in the gallbladder. Bile emulsifies (breaks into small particles) lipids (fats), which aids in the mechanical digestion of fats. The pancreas and gland cells of the small intestine secrete digestive enzymes that chemically break down complex food molecules into simpler ones. These enzymes include trypsin (for protein digestion), amylase (for carbohydrate digestion), and lipase (for lipid digestion). When food passes through the duodenum, digestion is complete.

From the duodenum, chyme passes to the jejunum and ileum. Here, tiny villi (finger-like projections) cover the walls of the small intestine. The cells that line the villi are covered with small projections called microvilli (brush border). These projections increase the surface area of the small intestine, allowing the chyme to contact more of the small intestine wall. The increased contact causes more efficient food absorption.

During food absorption, food molecules enter the bloodstream through the intestinal walls. Capillaries (microscopic blood vessels) within the villi absorb products of protein and carbohydrate digestion. Lymph vessels (lacteals) within the villi absorb products of fat digestion and eventually lead to the bloodstream.

From the small intestine, digested products travel to the liver, one of the body's most versatile organs. Hepatocytes (liver cells) detoxify (filter) blood of harmful substances such as alcohol and ammonia. And, hepatocytes store fat-soluble vitamins and excess substances such as glucose (sugar) for release when the body requires extra energy.

Explanation: