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Human Body Study

Tissues

A tissue is a group of similar cells that work together on a shared task. Despite the body’s complexity, there are only four basic tissue types — every organ is some combination of them.

The four tissue types in a generalized organ wall A layered cross-section showing the four tissue types stacked as they combine to build an organ. Each label links to the article for that type: epithelial, connective, muscle and nervous tissue. basement membrane a generalized organ wall free surface Epithelial tissue Connective tissue Muscle tissue Nervous tissue The four tissue types, layered as they combine to build an organ — schematic, not to scale.

The four tissue types

Section titled “The four tissue types”
  • Epithelial tissue — covers and lines surfaces: skin, the gut, the airways, blood vessels. It protects, absorbs, and secretes.
  • Connective tissue — supports and binds. An unusually broad category: bone, cartilage, tendons, fat, and even blood are connective tissues.
  • Muscle tissue — generates force and movement. Three kinds: skeletal, cardiac, and smooth.
  • Nervous tissue — generates and conducts electrical signals; the basis of the brain, spinal cord, and nerves.

Why it matters

Section titled “Why it matters”

Tissues are the bridge between cells and organs. Knowing the four types makes every organ easier to understand: an organ is simply a particular arrangement of these four fabrics.