What groups of cells are called tissues? To understand this issue, it is necessary to recall the features of their structure and functioning. We will try to cope with this in our article.
What groups of cells are called tissues
Tissue is considered to be a group of cells. But not all of them are capable of forming such structures. To understand what groups of cells are called tissues, it is necessary to assimilate the main condition. It lies in the fact that all cells must have similar structural features, and therefore, perform the same functions. Only then can such a structure be considered a fabric. In addition, the composition of many of them in varying amounts includes an intercellular substance that combines all the components into a single whole.
Tissue cell structure
All cells of the body have a general plan of structure. They consist of the surface apparatus, cytoplasm, organelles and inclusions. But depending on the type of tissue, the cells have their own characteristics. For example, neurons are composed of the body and processes. This structure provides a single work of the whole organism and its connection with the environment. According to the processes, information encrypted in the form of a nerve impulse is transmitted through cells and tissues.
The difference between multicellular and colonial organisms
Not all organisms consisting of a large number of cells have tissues. A vivid example of this is algae. Indeed, their body is formed by many cells, but each of them works separately, as a separate system. They are connected only anatomically, since their shells are adjacent to each other. The body of algae is called the thallus or thallus. But volvox is a colony. It is also formed by a large number of isolated cells. But they do not adjoin each other, but are surrounded by a common shell. She binds them into a single organism. In multicellular organisms, cells are combined into groups according to structural features, which allow them to collectively perform certain functions.
Plant tissue
Each group of organisms has its own structural features. Cells, tissues and organs of plants, for example, are able to carry out a complex process of nutrition - photosynthesis. This is due to the presence of specialized organelles called chloroplasts. But this is not the only characteristic feature of these organisms.
Plant tissues are represented by five species. It is integumentary, basic, mechanical, conductive and educational. The first of them protects the internal contents from dangerous environmental influences and metabolizes. Therefore, the integumentary tissue consists of tightly fitting small cells that have pores. It can be alive - peel, and dead, lignified - cork. The main tissue fully lives up to its name, since it really makes up almost the entire body. Its cells are large, loose. They contain chlorophyll.
Mechanical tissue allows plant organs to occupy a specific position in space. At one time, this became one of the conditions for plants to land. The elements of conductive tissues are vessels and sieve tubes. These hollow cells of elongated shape provide an upward and downward flow of substances in the plant. The cells of the educational tissue are living and constantly dividing, forming elements of all other types of tissues.
Animal tissue
The animal body has other types of cells. Tissues of these organisms are represented by epithelial, connective, muscle and nervous. In the structure of each of them there is a clear relationship between its structure and functions. Epithelial tissue cells are small, tight-fitting, like a shield. Therefore, they provide reliable protection. Examples of connective tissue are blood, adipose, bone, and cartilage. Since they form the basis of the body, their elements are large and are found in large amounts of intercellular substance. Muscular movement of the body in space. Its cells are called myofibrils. Each of them is capable of reduction. Nerve tissue provides a connection between the body and the environment, as it is formed by cells with processes that form a dense network.
So, what groups of cells are called tissues? The answer is simple: only those that are similar in structure and function. Due to its diversity, the cells of all organisms are able to form several types of tissues, each of which is important for functioning.