Epithelium

Epithelium is the tissue that covers the outer surface of the body and lines its hollow structures, excluding blood and lymphatic vessels. The epithelium separates the body from the external environment and also forms glands. The tissue is formed from embryonic ectoderm and endoderm.

Epithelial cells can be flat and scaly (squamous), cubic (cuboidal) or columnar (columnar). The latter may have cilia or microvilli, or secrete mucus or some other substances. The cells are located on the basement membrane, which separates the epithelial layer from the underlying connective tissue.

The epithelium can be single-layered, simple (simple), consisting of a single cell layer, and multilayered, multirowed (pseudostratified), in which the nuclei are arranged in layers, but virtually all cells lie on the basement membrane.

Single-layer epithelium can perform the functions of absorption, transportation and secretion of substances, and also protect tissues from environmental influences. Stratified epithelium is found in areas where additional protection is required, such as the skin and mucous membranes.

In addition, specialized cells may be found in the epithelium, such as goblet cells that secrete mucus to protect tissues and cells with sensory hairs that respond to external stimuli.

An important aspect of the epithelium is its ability to regenerate. Epithelial cells have a high ability to divide and replace damaged cells, allowing the tissue to quickly recover after injury or infection.

In conclusion, the epithelium is an important tissue that performs a number of functions including protection, absorption, transport and secretion of substances. Its ability to regenerate makes it an essential element in tissue repair after injury or infection.

Epithelium: structure, functions and types

Epithelium is one of the main types of tissue that covers the outer surface of the body and lines the hollow organs inside the body. It plays an important role in protecting the body from the external environment, and also ensures the functioning of the glands. In this article we will look at the structure, functions and types of epithelium.

The structure of the epithelium

Epithelial tissue is made up of cells that are tightly connected to each other. The cells are located on the basement membrane, a thin network of proteins that separates the epithelium from the connective tissue. The basement membrane consists of two layers: the basal and reticular lamina.

Epithelial cells can be flat and scaly (squamous), cubic (cuboidal) or columnar (columnar). The latter may have cilia or microvilli, or secrete mucus or some other substances (see Goblet cell (epithelial)). Epithelial cells may also have different specializations associated with performing specific functions.

Functions of the epithelium

Epithelial tissue performs several important functions. It protects the body from mechanical, chemical and bacterial influences from the external environment. In addition, the epithelium participates in the excretory function, forming glands, and ensures the transport of substances through its cells.

The epithelium also plays an important role in regulating metabolism and maintaining homeostasis in the body. For example, some epithelial cells absorb nutrients from food that passes through the stomach and intestines, while other cells secrete harmful substances from the blood and remove them from the body.

Types of epithelium

There are several types of epithelium, which differ in the shape and function of their cells. Single-layer simple epithelium (simple) consists of one layer of cells and performs the function of absorption and transport of substances. It is found in the intestines, lungs and kidneys.

Stratified pseudostratified epithelium (pseudostratified) consists of several layers of cells, but they are all attached to the basement membrane. It is found in the respiratory system, where it helps protect the lungs from harmful substances.

Cuboidal epithelium consists of cubic cells that perform the function of excretion. It is found in glands such as the salivary and sweat glands.

Columnar epithelium (columnar) consists of tall columnar cells, which also perform the function of excretion. It is found in the stomach, intestines and other hollow organs.

In addition, there is also a transitional epithelium, which is capable of changing its shape depending on the stretching of the organ. It is found in the bladder, ureters and urinary tract.

Conclusion

Epithelial tissue plays an important role in protecting the body from the external environment, ensures the functioning of glands and ensures the transport of substances through its cells. There are several types of epithelium, which differ in the shape and function of their cells. Understanding the structure and function of the epithelium can help to better understand the body's functioning and its defense mechanisms.

Epithelium is one of the most common tissues in the human body. It covers the surfaces of the body and the internal cavities of organs, protecting them from mechanical damage and the penetration of various infectious agents. The role of barrier function and protective properties determine the place of epithelial tissue in our lives. However, in the article I would like to dwell on some aspects of epithelial tissue and its functional significance in the human body.

Epithelial (from the Greek epitheleion - “epithelialized”) tissue is a tissue that protects its underlying structures from the physical, chemical and pathological effects of environmental factors. It is formed by a dense monolayer of prismatic or cuboidal epithelial cells, tightly adjacent to each other and usually covered with a supracellular slit-like membrane. Epithelial tissues secrete secretion proteins or special compounds, which makes them visible and gives the surface layer a mucous character.

Epithelial tissues are divided into types according to several criteria. Depending on the origin, the following groups of epithelia are distinguished: - Embryo