The biochemical process in which various types of enzymes break down complex food into simple and absorbable food is called digestion. Hydra can digest food such as proteins, fats and simple carbohydrates. They cannot digest starch or complex carbohydrates. Undigested food comes out through the mouth. Hydra digestion takes place in two stages. Extracellular digestion and intracellular digestion.
1. Extracellular digestion: The process in which food is digested outside the cells inside the stomach, alimentary canal and celandine is called extracellular digestion. As soon as the food material reaches the cilentron, the mouth pore closes. The prey or food is killed by the action of the enzyme. The contraction and expansion of the body wall breaks the prey into smaller particles. Food is digested under the influence of enzymes secreted from glandular cells. Proteins are broken down into polypeptides. Lipid food is not digested here. Dr. Siddiq Publications
2. Intracellular digestion: The process in which food is digested inside the cytoplasm of the cell is called intracellular digestion.
Partially digested food particles in the cilantro are converted into smaller particles by the contraction-expansion of the body. Some of the food particles turn into liquid with the help of the passage. The food particles then enter the food cavity in the cytoplasm. Enzymes secreted from the cytoplasm digest food. Food is digested first in an acidic and then in an alkaline phase. Proteins are broken down into amino acids and lipids are broken down into fatty acids and glycerol. Dr. Siddiq Publications