Functions of muscular tissues, types and structure

The organism of all animals, including man, consists of four types of tissues: epithelial, nervous, connective and muscular. The latter will be discussed in this article.

Varieties of muscle tissue

It can be of three types:

• Cross-striped;
• Smooth;
• Heart.

The functions of muscle tissues of different species are somewhat different. Yes, and the structure too.

Where are the muscle tissues in the human body?

Muscle tissues of different species occupy different positions in the body of animals and humans. So, from heart muscle, as the name implies, a heart is built.

Skeletal muscles are formed from the striated muscle tissue.

Smooth muscles lining the inside of the cavity of the organs, which need to contract. This, for example, intestines, bladder, uterus, stomach, etc.

The structure of muscle tissue of different species varies. Let's talk about it in more detail.

How is the muscle tissue?

It consists of large cells - myocytes. They are also called fibers. Muscle tissue cells have several nuclei and a large number of mitochondria - organoids responsible for energy production.

In addition, the structure of the muscle tissue of humans and animals provides for a small amount of intercellular substance containing collagen, which gives the muscles elasticity.

Let's look at the structure and functions of muscle tissues of different species separately.

Structure and role of smooth muscle tissue

This tissue is controlled by the autonomic nervous system. Therefore, a person can not consciously contract muscles constructed from smooth tissue.

It is formed from a mesenchyme. This is a type of embryonic connective tissue.

This tissue is reduced much less actively and quickly than the striated.

The smooth tissue is built of spindle-shaped myocytes with pointed tips. The length of these cells can be from 100 to 500 micrometers, and the thickness - about 10 micrometers. The cells of this tissue are mononuclear. The nucleus is located in the center of the myocyte. In addition, such organelles as agranular EPS and mitochondria are well developed. Also in the cells of smooth muscle tissue there is a large number of inclusions from glycogen, which are the reserves of nutrients.

An element that provides a reduction in muscle tissue of this species is myofilaments. They can be constructed from two contractile proteins: actin and myosin. The diameter of myofilaments, which consist of myosin, is 17 nanometers, and those that are built of actin - 7 nanometers. There are also intermediate myofilaments, whose diameter is 10 nanometers. Orientation of myofibrils longitudinal.

The composition of the muscle tissue of this species also includes an intercellular substance from collagen, which provides a link between the individual myocytes.

Functions of muscle tissue of this species:

• Sphincter. It consists in the fact that smooth muscles are arranged from smooth tissues, regulating the transition of contents from one organ to another or from one part of the organ to another.
• Evacuation. The fact is that smooth muscles help the body to remove unnecessary substances, and also take part in the birth process.
• Creating a lumen of blood vessels.
• Formation of the ligamentous apparatus. Thanks to him, many organs, such as, for example, the kidneys, are held in place.

Now let's look at the next kind of muscle tissue.

Striped striped

It is regulated by the somatic nervous system. Therefore, a person can consciously regulate the work of muscles of this species. Skeletal musculature is formed from the striated tissue.

This fabric consists of fibers. These are cells that have a lot of nuclei located closer to the plasma membrane. In addition, they contain a large number of glycogen inclusions. Organoids such as mitochondria are well developed. They are near the contractile elements of the cell. All other organelles are localized near the nuclei and are poorly developed.

The structures by which the striated tissue is contracted are myofibrils. Their diameter ranges from one to two micrometers. Myofibrils occupy most of the cell and are located in its center. Orientation of myofibrils longitudinal. They consist of light and dark discs that alternate, which creates a transverse banding of the tissue.

Functions of muscle tissue of this type:

• Provide for the movement of the body in space.
• Responsible for the movement of parts of the body relative to each other.
• Capable of maintaining the body's posture.
• Participate in the process of temperature regulation: the more actively the muscles contract, the higher the temperature. When freezing, the striated muscles may begin to contract involuntarily. This explains the trembling in the body.
• Perform a protective function. This is especially true for abdominal muscles, which protect many internal organs from mechanical damage.
• They act as depots of water and salts.

Cardiac muscle tissue

This fabric is similar to both cross-striped and smooth. Like smooth, it is regulated by the autonomic nervous system. However, it is reduced as actively as the striated.

It consists of cells called cardiomyocytes.

Functions of muscle tissue of this type:

• It is only one: ensuring the movement of blood throughout the body.