In the body of plants and animals, various types of tissue, cells are isolated. Tissues can differ both in the structure of cells and in the structure of the intercellular substance, as well as in their functions. Different types of cells may differ in shape, size, the presence or absence of some organelles. Different types of cells form different types of tissues. Consider the main cell types.
Vegetable, mushroom, animal, bacterial
This is a classification of cells depending on the organisms that are built from them. Here is a comparison table showing these cell types, their differences and similarities.
| Vegetable | Animal | Mushroom | Bacterial | |
| Core | is | is | is | no |
| Cell wall | from cellulose | no (a glycocalyx is located above the membrane) | from chitin | from murein |
| Plasma membrane | is | is | is | is |
| Reserve substance | starch | glycogen | glycogen | volutin |
| Mitochondria | is | is | is | no |
| Plastids | is | no | no | no |
| Ribosome | is | is | is | is |
| Golgi complex | is | is | is | no |
| Endoplasmic reticulum | is | is | is | no |
| Lysosomes | is | is | is | no |
| Vacuoles | is | no | no | some |
| Method of obtaining energy | breathing | breathing | breathing | fermentation |
| Method of obtaining organic substances | photosynthesis | outside | outside | from outside, chemosynthesis or photosynthesis |
Cell types of different tissues
Different cells form different tissues. In addition, the same tissue is made up of several different types of cells.
Epithelial cells
They are called epitheliocytes. These are polarly differentiated cells located closely to each other. They can be cubic, flat or cylindrical. Epitheliocytes are usually located on the basement membrane.
Types of cellsconnective tissue
There are several types of connective tissue:
- reticular;
- dense fibrous;
- loose fibrous;
- bone;
- cartilaginous;
- fatty;
- blood;
- lymph.
Each of these tissues has different cells and intercellular substance. Reticular tissue is composed of reticulocytes and reticular fibers. Reticulocytes can form hematopoietic cells and macrophages - cells responsible for protecting the body from viruses.
Dense fibrous tissue consists mainly of fibers, and loose - of an amorphous substance. Dense fibrous tissue gives the organs elasticity, while loose fibrous tissue fills the gaps between the internal organs.
Bone tissue contains various types of cells: osteogenic, osteoblasts, osteoclasts and osteocytes. The latter are the main cells of the tissue. Osteogenic cells are undifferentiated cells that can form osteocytes, osteoblasts, and osteoclasts. Osteoblasts produce substances that make up the intercellular substance of bone tissue. Osteoclasts are responsible for the resorption of bone tissue when needed. Some scientists do not classify them as bone cells.
Cartilage tissue consists of chondrocytes, chondroclasts and chondroblasts. The first are in the outer layer of cartilage. They have a spindle shape. Chondroblasts are located in the inner layer. They are oval or round in shape. Chondroclasts are responsible for recycling old cellscartilage.
Adipose tissue is made up of only one type of cell: lipocytes. They contain a large amount of spare fats.
Diversity of blood and lymph cells
Blood contains numerous types of cells called blood cells. These are erythrocytes, platelets and leukocytes, which are divided into several types. Erythrocytes have a flattened round shape. They contain the protein hemoglobin, whose function is to transport oxygen throughout the body. Platelets are small non-nucleated cells. They are responsible for blood clotting. Leukocytes represent the immune system of humans and animals.
Leukocytes are divided into two large groups: granular and non-granular. The former include neutrophils, eosinophils and basophils. The former are able to carry out phagocytosis - eating hostile bacteria and viruses. Eosinophils are also capable of phagocytosis, but this is not their main role. Their main function is to destroy histamine, which is released by other cells during the inflammatory process, which can cause swelling. Basophils mediate inflammation and secrete eosinophilic chemotactic factor.
Nongranular leukocytes are divided into lymphocytes and monocytes. The first are divided into three classes depending on their functions. There are T-lymphocytes, B-lymphocytes and null lymphocytes. B-lymphocytes are responsible for the production of antibodies. T-lymphocytes are responsible for recognizing foreign cells, as well as stimulating the work of B-lymphocytes and monocytes. Null lymphocytes are reserved.
Monocytes, or macrophages, toocapable of phagocytosis. They destroy viruses and bacteria.
Nervous tissue
There are the following types of nerve cells:
- actually nervous;
- glial.
Nerve cells are called neurons. They consist of a body and processes: a long axon and short branched dendrites. They are responsible for the formation and transmission of momentum. Depending on the number of processes, unipolar (with one), bipolar (with two) and multipolar (with many) neurons are distinguished. Multipolar are most common in humans and animals.
Glial cells perform supporting and nutritional functions, providing stable accommodation in space and supply of nutrients to neurons.
Muscle cells
They are called myocytes, or fibers. There are three types of muscle tissue:
- striped;
- heart;
- smooth.
Depending on the type of tissue, myocytes are different. In striated tissue, they are long, elongated, have several nuclei and a large number of mitochondria. In addition, they are intertwined. Smooth muscle tissue is characterized by smaller myocytes with fewer nuclei and mitochondria. Smooth muscle tissue cannot contract as quickly as striated muscle tissue. Cardiac muscle is composed of myocytes, more similar to those of striated tissue. All myocytes contain contractile proteins: actin and myosin.
