“Describe the hydra’s nutrition and digestion processes” - probably not everyone will be able to complete such a task. After all, the school course of zoology does not consider this question in too much detail. Let's refresh our knowledge together and consider how hydra eats.
Structural Features of Hydra
Freshwater hydra is a typical representative of the type of Intestinal. It is on the example of this multicellular animal that the features of this systematic unit are studied. The hydra's body shape resembles a small stalk that is attached to the base. They can serve as the bottom of a reservoir, stones or other substrate. Tentacles are located on the free end of the body. With their power, the hydra preys on small aquatic animals, for example, ciliates, small crustaceans, or even sometimes fish fry.
Cell specialization
We continue to carry out the task "Describe the hydra nutrition and digestion processes." To understand this issue, we first find out how this animal works. Despite the fact that hydra is a multicellular organism, it does not have 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-muscle hydra moves. But nerve cells scattered throughout the body interconnect with the environment. There are hydra and gametes in the body - eggs and sperm. They carry out the process of sexual reproduction of intestinal.
What and how does hydra eat
Small unicellular and vertebrate animals that move near the freshwater hydra are very easy prey for her. The animal catches them with tentacles and sends them into the intestinal cavity for further digestion. But before that, the animal paralyzes its prey. Features of hydra are the presence of stinging cells. Each of them consists of a capsule in which the thread is twisted. On top of the stinging cell is a sensitive hair. When the victim touches him, the thread unfolds and pierces the body with force. With this, poison enters the body of the prey, completely paralyzing it. The stinging cell performs its function only once, after which it dies. But in the body of the hydra, new ones immediately arise. This occurs as a result of the division of educational cells, which give rise to all other types.
Intestinal cavity
So, thanks to the coordinated work of tentacles and stinging cells, prey is completely in the intestinal cavity of the hydra. Here it is exposed to the action of enzymes of glandular cells. They produce biological catalysts, under the influence of which large parts of the food break up into fragments. It is worth saying that the digestive system of all representatives of the type of entero-celiac closed type. It is quite primitive in structure and is represented only by the oral opening and intestinal cavity. The remaining departments are missing. This means that undigested food debris is 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, we can see progressive features. If in the first multicellular animals - sponges - the feeding process was a filtration of edible particles from water, then the hydra hunts on its own, has an analogue of the glands and carries out chemical processing of food. So the complexity of the structure can be seen with the naked eye. So we partially approached the answer to the task "Describe the hydra nutrition and digestion processes".
Cell digestion
But the digestive process in hydra, like in all intestinal cavities, is not limited to the intestinal cavity. After decaying into small fragments of a particle, they are exposed to other specialized formations. These are the digestive cells that are in the inner layer of the body of a freshwater hydra. They have their own flagella, which are able to create a stream of water. With it, food enters the surface of these cells. Then it is captured by the pseudopods. Thus, the food is inside a specialized cell. This is the final stage of the digestion process. It ends in the digestive vacuoles with hydrolytic enzymes. Here, undigested residues are formed that are removed through the mouth opening.
Thus, freshwater hydra is simultaneously characterized by two types of digestion: cavitary and cellular. The first occurs in the intestinal cavity with the help of glandular cells that secrete enzymes to break down food. The second is the final stage. It is characteristic of specialized digestive cells and vacuoles. I think that now the task “Describe the hydra nutrition and digestion processes” will not cause any difficulties for anyone.