Knowledge Encyclopedia Human Body

Book Preface

WHAT MAKES A BODY?

The human body is made from the same components as every other living thing. It is the way that they are put together that makes our bodies uniquely human. The basic materials are simple chemicals such as water, carbon, and oxygen, but they join to create more complex compounds. Trillions of microscopic cells become the building blocks of life, grouping together to form skin, bone, blood, and organs, until the body becomes complete.

TYPES OF TISSUE
Tissues are groups of connected cells. Many tissues are made entirely from one type of cell. The four main types of tissue in the human body are connective, epithelial, muscular, and nervous.

THE HARDEST TISSUE IN THE HUMAN BODY IS TOOTH ENAMEL.

Nerve tissue
Large groups of nerve cells create nervous tissue. This forms the brain, spinal cord, and masses of nerves that work together in the nervous system, the body’s high-speed communications network.

Epithelial tissue
Made up of three main shapes of cell, epithelial tissue lines and covers surfaces inside and outside the body. It forms skin and the linings of body cavities such as the gut and lungs.

Muscle tissue
Built from long, thin cells, muscle tissue can relax and contract to allow muscles to move bones. It also helps sustain blood pressure and carry food through the digestive system.

Connective tissue
This dense tissue is the body’s
“glue”, filling the space between other tissues and organs, and binding them together. Examples include adipose tissue (fat), bone, and blood.