Describe the processes of feeding and digestion of hydra: features of the physiology of coelenterates

"Describe the processes of nutrition and digestion hydra" - to fulfill this task will certainly not all. After all, the school course of zoology does not consider this question in great detail. Let's refresh our knowledge together and consider how the hydra feeds.

Features of the structure of hydra

Freshwater hydra is a typical representative of the type of the intestinal. It is on the example of this multicellular animal that the characteristics of this systematic unit are studied. The shape of the hydra body resembles a small stalk that is attached to the base. They can serve as the bottom of a pond, rocks or other substratum. At the free end of the body are the tentacles. With their power the hydra hunts small aquatic animals, for example, infusorians, small crustaceans or even sometimes fish fry.

Specialization of cells

We continue to carry out the task "Describe the processes of feeding and digestion hydra." To understand this question, first we will find out how this animal is arranged. Despite the fact that the hydra is a multicellular organism, it has no real tissues. But her body is formed not by the same, but by specialized cells, each type of which performs its function. So, with the help of skin-muscular hydra moves. But the nerve cells scattered throughout the body, interact with the environment. There are hydras and gametes in the body - ovules and spermatozoa. They carry out the process of sexual reproduction of coelenterates.

What and how to eat hydra

The small unicellular and vertebrate animals that move near the freshwater hydra are very easy prey for it. The animal catches them with the help of tentacles and sends them to the intestinal cavity for further digestion. But before that, the animal paralyzes its victim. Features of hydra are the presence of stinging cells. Each of them consists of a capsule, in which a thread is twisted. Above the stinging cell is a sensitive hair. When it touches the victim, the thread unfolds and pierces the body with force. With this, a poison penetrates into the prey's body, completely paralyzing it. The cage performs its function only once, after which it dies. But in the hydra's body, new ones immediately appear. This happens as a result of the division of educational cells, which give rise to all other types.

Intestinal cavity

So, thanks to the concerted work of tentacles and stinging cells, the entire extraction is in the intestinal cavity of the hydra. Here it is exposed to the action of enzymes of glandular cells. They produce biological catalysts, under which large parts of food break up into fragments. It is worth saying that the digestive system of all representatives of the type of intestinal closed type. It is quite primitive in structure and is represented only by the oral opening and the intestinal cavity. The remaining departments are absent. This means that undigested food remains removed through the mouth opening. Of course, such a digestive system is quite simple and primitive. However, if we consider this issue in the light of evolution, then we can see progressive features. If the first multicellular animals - sponges - the process of feeding was the filtration of edible particles from water, then the hydra itself hunts, has an analog of glands and carries out chemical processing of food. So the complication of the structure can be seen with the naked eye. We partially approached the answer to the task "Describe the processes of feeding and digestion hydra."

Cellular digestion

But the digestive process of the hydra, like all coelenterates, does not limit the intestinal cavity. After the breakup into small fragments of the particle, they are subjected to the action of other specialized entities. These are digestive cells that are found in the inner layer of the body of freshwater hydra. They have their own flagella, which can create a flow of water. With it, food comes to the surface of these cells. Then it is captured by the pseudopods. Thus, food is inside a specialized cell. This place is the final stage of the digestion process. It ends in the digestive vacuoles with the help of hydrolytic enzymes. Here, undigested residues are formed, which are removed through the mouth opening.

Thus, freshwater hydra is characterized simultaneously by digestion of two types: cavitary and cellular. The first occurs in the intestinal cavity with the help of glandular cells that secrete enzymes for the breakdown of food. The second is the final stage. It is characteristic of specialized digestive cells and vacuoles. I think that now the task "Describe the processes of feeding and digestion hydra" will not cause any difficulties.