Question

Gastrodermis of Hydra is mainly made of
A. Musculo Epithelial cells
B. Musculonutritive cells
C. Sensory cells
D. Cnidoblast cells

Answer 1

Hint:-The inner layer of Hydra has specialized gland cells that secrete the digestive enzymes to assist in the process of digestion. Some of the cells of this layer swallow the food particles. These cells perform intracellular digestion of the macromolecules of food.

 Complete step-by-step solution:-
Hydra belongs to the class Hydrozoa of the phylum Cnidaria. It is a diploblastic organism and has two tissue layers. The epidermis is the outer layer and is derived from the ectoderm while the gastrodermis is the inner layer.
The gastrodermis lines the gastrovascular cavity in Hydra and is involved in the digestion. The epidermis and gastrodermis are separated from each other by acellular mesoglea.
The epidermis and gastrodermis have several specialized cells. Musculo Epithelial cells are mainly present in the epidermis. These cell cylindrical cells. The muscular part of these cells forms longitudinal muscles involved in the contraction of the body.
Sensory cells are the elongated slender cells and have a large nucleus. These cells have both receptors and sensory portions and therefore, serve in receiving and transmitting the nerve impulses. Sensory cells are most abundant in the ectoderm.
Cnidoblasts are specifically abundant in the tentacles of Hydra. These cells are present in the epidermis and are derived from the interstitial epidermal cells. Cnidoblasts are involved in defence of the organism from the predators and also serve in obtaining the food.
As the name suggests, musculo nutritive cells are involved in nutrition. Since the gastrodermis is the layer of Hydra that serves in the digestion, these cells are present in the gastrodermis. The apical surface of these cells has thin microvilli that extend into the digestive cavity. Also called the digestive cells, they are filled with food vacuoles and serve to secrete the digestive enzyme into the gastrovascular cavity.
So, the correct answer is option B. Musculo Nutritive cells.

Note:- Gastrodermis is derived from the endoderm. Its main functions are secretion, digestion, and sensory. Therefore, it has the digestive cells, interstitial cells, and gland cells.