Made up of cells that line the inner and outer body surfaces, protects body and its internal organs, secretes substances such as hormones, and absorbs substances such as nutrients

Made up of cells that can contract and give the body the ability to move

Made up of neurons, or nerve cells, that carry electrical messages, make up the brain and other nervous tissues

Brownish pigment that gives skin much of its color

Outer layer of skin, consisting of epithelial cells

Lower layer of the skin, located directly beneath the epidermis

Thin tubular bundle of nervous tissue that extends from the brainstem and continues down the center of the back to the pelvis, protected by vertebrae

Structural and functional units of the nervous system, transmit electrical impulses

Complex network of nervous tissue that carries electrical messages through the body

Most complex organ of the human body and the control center of the nervous system

Extend from the cell body and receive nerve impulses from other neurons

Cable-like bundle of axons

Long extension of the cell body that transmits nerve impulses to other cells

Control levels of glucose in the blood, located near stomach, hormones include insulin and glucagon

“master gland”, attached to the hypothalamus, stores hormones and secretes pituitary hormones

System of glands that release chemical messenger molecules, called hormones, into the bloodstreams