The four animal tissues

Four tissues, and between them they cover, connect, move and control the entire body of a vertebrate.

Figure to be added

Figure 1.14 — a human figure with six tissues shown as circular micrographs and lines drawn to where each is found: connective tissue at the upper arm, nervous tissue at the brain, bone tissue at the hip, cardiac muscle tissue at the heart, smooth muscle tissue at the intestine, and epithelial tissue at the skin.

Epithelial tissue

Covers. Lines every surface of the body, inside and out, and protects what is underneath.

Connective tissue

Connects. Holds the other tissues and the organs together, and supports them. Blood and bone are both connective tissues.

Muscle tissue

Moves. Contracts and relaxes, and so produces every movement the body makes, including the ones you never think about.

Nervous tissue

Controls. Carries impulses from the sense organs to the brain and from the brain to the muscles.

Cover, connect, move, control

Those four verbs are the whole classification, and they are worth holding on to. Every characteristic in the next four skills follows from one of them — a tissue that covers a surface has to be packed tight, a tissue that connects needs something to hold cells apart in, a tissue that moves needs a good blood supply, and a tissue that controls needs to be long.

The four vertebrate tissues

Epithelial tissue covers, connective tissue connects and supports, muscle tissue moves, and nervous tissue carries impulses. Animal tissues are classified by what they do.