Tissues are groups of similar cells working together, and every organ is built from a mix of four basic types. Knowing them helps explain how the body is built and how it heals.
Epithelial tissue
Epithelium covers surfaces and lines cavities, such as the skin, the gut lining and the airways. It protects, absorbs and secretes, and it renews itself quickly.
Connective tissue
Connective tissue supports and binds other tissues. It includes bone, cartilage, tendons, fat and blood, and its cells sit in a matrix of fibers such as collagen.
Muscle tissue
Skeletal muscle moves the bones under voluntary control. Cardiac muscle pumps the heart, and smooth muscle lines the vessels, gut and airways, both without conscious control.
Nervous tissue
Neurons carry electrical signals, and supporting glial cells protect and feed them. Mature neurons rarely divide, so damage to the brain and spinal cord often lasts.
Healing
Epithelium and many connective tissues heal well, while heart muscle and nerve tissue heal mostly with scar. Good blood supply, nutrition and a clean wound speed healing.
| Tissue | Main job | Example |
|---|---|---|
| Epithelial | Covers, lines, secretes | Skin surface, gut lining |
| Connective | Supports and binds | Bone, tendon, fat, blood |
| Muscle | Contracts | Skeletal, cardiac, smooth |
| Nervous | Sends signals | Brain, nerves |
At the bedside
Wound care follows tissue biology: a clean, moist, well-perfused wound heals faster. Note the depth and any exposed fat, tendon or bone, since deeper wounds need more than a simple dressing.
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Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).