What Types of Tissue There Are in the Human Body
Scientists still can’t say for sure what the exact number of cells in the human body is. Approximately, there are somewhere between 30 and 40 trillion cells. However, experts have long learned to organize different cells into tissue, where cells have a similar structure, origin, and function.
5-Minute Crafts would like to tell you about the different types of tissue the human body consists of and explain their purpose.
There are 4 basic types of tissue in the human body: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. Each of these has a specific structure and function.
Epithelial tissue covers the surface of the human body, lines the mucous membranes of internal organs, forms the inner membrane of blood vessels and body cavities (surface epithelium), and also forms the glands of the human body (glandular epithelium).
Epithelial tissue includes our skin, mucous membranes of the mouth, nasal cavity, digestive tract, etc.
The characteristics of epithelial tissue:
- It consists of cells closely packed with almost no intercellular spaces between them.
- There are no blood vessels in epithelial tissue, so it gets nutrients from the adjacent connective tissue.
- The epithelium is very sensitive and has its own nerve supply.
- Epithelial tissue has a high rate of cell division that allows the tissue to continually renew and repair itself by replacing dead or injured cells with new ones.
- Epithelial tissue is characterized by polarity. This means the cells that are located closer to the surface of the body, like the lumen of an internal organ, a gland duct, and the cells that are located deeper, have different structures.
Epithelial tissue functions:
- Protection is one of the most important functions of epithelial tissue. The epithelium covers our body and protects the underlying cells from drying out, getting damaged, and coming into contact with toxins.
- Epithelial tissue also performs an exchange function. Some cells of epithelial tissue (like the intestinal epithelium) are able to absorb water and nutrients, directing them further into the body. In addition, the epithelium performs filtration and removes metabolic products from the body.
- The glandular epithelium is responsible for the secretion of the body. The glands of external, internal, and mixed secretion formed by this epithelium secrete hormones, enzymes, and other substances that are responsible for many functions in the body.
- Some cells of epithelial tissue also perform a receptor function. They can recognize sensory information and convert it into nerve impulses. And the epithelial cells of the nasal mucosa, which have special cilia, allow the sensation of odor.
Connective tissue features:
- Unlike epithelial tissue, whose cells are in close contact with each other, connective tissue cells are dispersed in a substance called the intercellular matrix.
- Different types of connective tissue can differ significantly from each other, but usually, each of them has 3 main components: cells, a large amount of a basic substance, and protein fibers. The basic substance can be liquid or solid, like in bones.
- All types of connective tissue, except for cartilage, contain a large number of blood vessels. A good blood supply facilitates the transport of nutrients, oxygen, and water and the elimination of waste.
Connective tissue functions:
- It connects various tissues and organs of the body and protects internal organs.
- Dense connective tissue, such as that of bones and cartilage, forms the skeleton of the body, providing support for the internal organs.
- Lymphocytes and leukocytes (which are also cells of connective tissue) perform a protective function, protecting the body from various infections.
- Blood participates in the nourishing process of the body, carrying oxygen, water, and nutrients to other cells and tissues.
- The adipose tissue located under the skin stores energy and provides insulation to the body.
Muscle tissue is a soft tissue that, together with tendons (connective tissue), forms the human muscular system and participates in the movement of the body.
Muscles in our body (including muscles of the face, torso, and limbs) and the heart consist of muscle tissue. Additionally, muscle tissue lines the organs of the digestive, respiratory, and reproductive systems.
Muscle tissue features:
- Muscle tissue is made of cells that are capable of contraction.
- It easily reacts to stimuli.
- Muscle tissue is characterized by elasticity and extensibility, which allow it to stretch without tearing and easily return to the previous state.
- There are 3 types of muscle tissue: smooth, skeletal, and cardiac. Skeletal muscle is responsible for body movement. Cardiac muscle contracts the heart, pumping blood through it. Smooth muscle forms organs, such as the stomach and bladder, and enables them to function effectively.
Muscle tissue functions:
- Muscles are responsible for bodily movement and for keeping the body in one position or another.
- Skeletal muscle provides stability to the joints and supports the organs within the body.
- Muscles help to maintain the correct body temperature by generating heat.
- The heart muscle is the main “pump” in the human body, which supplies blood.
- Smooth muscle is responsible for the movement of food through the digestive system.
- Smooth muscle is involved in regulating blood pressure by altering systemic vascular resistance.
Nervous tissue makes up the human nervous system. Thanks to this, you can control your body.
The nerve ganglia, brain, and spinal cord all consist of nervous tissue.
Nervous tissue features:
Nervous tissue functions:
- Neurons of nervous tissue transmit impulses from the 5 senses to the central nervous system, allowing us to feel the world around us.
- It ensures the coordinated activity of all organ systems.
- It controls all body movements.
- It allows the body to actively respond to changes in the external environment.
- It participates in the processes of excitement and relaxation. It also plays an important role in the process of digestion, causes the pupils of the eyes to dilate, and increases sweat secretion and the heart rate.