Tissues (biology)

Tissues are groups of similar cells that work together to perform a specific function. They are the material of which organs and organ systems are composed. In biology, tissue is a cellular organizational level between cells and a complete organism.

Types of Tissues[edit | edit source]

There are four basic types of tissues in the body of all animals, including humans. These are:

Epithelial tissue: This tissue covers the body surface and lines its cavities, forming a barrier to keep the body's internal and external environments separate. It also forms many of the body's glands.

Connective tissue: This tissue supports, connects, or separates different types of tissues and organs in the body. It includes bone, blood, and lymph tissues.

Muscle tissue: This tissue is made of cells that have the unique ability to shorten or contract in order to produce movement of the body parts.

Nervous tissue: This tissue is composed of neurons and neuroglia, which transmit and process information in the brain, spinal cord, and peripheral nerves.

Structure and Function[edit | edit source]

Tissues are organized into a three-dimensional structure, usually serving a particular function. For example, the epithelium lines the internal and external surfaces of the body, protecting it from dehydration, injury, and microbial invasion. Connective tissue, such as bone and cartilage, provide a framework for the body, giving structure and support to the organism's organs.

Tissue Repair[edit | edit source]

When tissues are damaged, the body initiates a process of tissue repair to replace dead and damaged cells. This process involves cell division, migration, and differentiation of healthy cells in the surrounding area.