In the body of plants and animals, various types of tissue and cells are secreted. Tissues can differ both in the structure of cells and in the structure of intercellular substance, as well as in their functions. Different types of cells may differ in the shape, size, presence or absence of certain organelles. Different types of cells form different types of tissues. Consider the main types of cells.
Plant, 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 |
| Nucleus | there is | there is | there is | no |
| Cell wall | cellulose | no (glycocalyx is located above the membrane) | from chitin | from murein |
| Plasma membrane | there is | there is | there is | there is |
| Reserve substance | starch | glycogen | glycogen | volutin |
| Mitochondria | there is | there is | there is | no |
| Plastids | there is | no | no | no |
| Ribosomes | there is | there is | there is | there is |
| Golgi complex | there is | there is | there is | no |
| Endoplasmic reticulum | there is | there is | there is | no |
| Lysosomes | there is | there is | there is | no |
| Vacuoli | there is | no | no | some |
| Way to get energy | breath | breath | breath | fermentation |
| The method of obtaining organic substances | photosynthesis | from the outside | from the outside | externally, chemosynthesis or photosynthesis |
Types of cells of different tissues
Different cells form different tissues. In addition, the same tissue consists of several different types of cells.
Epithelial cells
They are called epithelial cells. These are polar differentiated cells located closely to each other. They can be cubic, flat or cylindrical in shape. Epithelial cells are usually located on the basement membrane.
Types of connective tissue cells
Connective tissue exists in several types:
- reticular
- dense fibrous;
- loose fibrous;
- bone;
- cartilaginous;
- fatty;
- blood;
- lymph.
Each of these tissues has different cells and intercellular substance. Reticular tissue consists of reticulocytes and reticular fibers. Hematopoietic cells and macrophages can be formed from reticulocytes - the cells responsible for protecting the body from viruses.
Dense fibrous tissue predominantly consists of fibers, while loose tissue consists of an amorphous substance. Dense fibrous tissue gives the organs elasticity, while loose 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 - these are undifferentiated cells from which osteocytes, osteoblasts and osteoclasts can form. Osteoblasts produce the substances that make up the intercellular substance of bone tissue. Osteoclasts are responsible for resorption of bone tissue, if necessary. 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 fusiform shape. Chondroblasts are located in the inner layer. They have an oval or round shape. Chondroclasts are responsible for the disposal of old cartilage cells.
Adipose tissue consists of only one type of cell: lipocytes. They contain a large amount of spare fats.
A variety of blood cells and lymph
Blood contains numerous types of cells called blood cells. These are red blood cells, platelets and white blood cells, which are divided into several types. Red blood cells have a flattened round shape. They contain hemoglobin protein, the function of which is the transport of oxygen throughout the body. Platelets are small, nuclear-free cells. They are responsible for blood coagulation. White blood cells are the immune system of humans and animals.
White blood cells 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 the histamine secreted by other cells in the inflammatory process that can cause swelling. Basophils mediate inflammation and secrete the eosinophilic chemotactic factor.
Non-granular white blood cells 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 the recognition of foreign cells, as well as the stimulation of B-lymphocytes and monocytes. Zero lymphocytes are reserve.
Monocytes, or macrophages, are also capable of phagocytosis. They destroy viruses and bacteria.
Neural tissue
The following types of nerve cells exist:
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. Unipolar (with one), bipolar (with two) and multipolar (with many) neurons are distinguished depending on the number of processes. Multipolar are most common in humans and animals.
Glial cells perform supporting and nutritional functions, providing a stable placement in space and the supply of nutrients to neurons.
Muscle cells
They are called myocytes, or fibers. There are three types of muscle tissue :
Depending on the type of tissue, myocytes are different. In the 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 is not able to contract as quickly as striated. The heart muscle consists of myocytes, more similar to those in striated tissue. All myocytes contain contractile proteins: actin and myosin.