_______________-a fibrous protein found in the epidermis, hair, and nails that makes those structures hard and water resistant

_________________________________ -toward the midline of the body

_______________-relating to the head, neck, and trunk; one of the two major divisions of the body

___________-muscle that reverses, or opposes, the action of another muscle

________________-a dark brown to black pigment formed by cells called melanocytes occurring in the hair, skin, and iris of the eye in people and animals; responsible for tanning of skin exposed to sunlight

____________-a specialized cell that transmits electrical signals; a nerve cell

__________-white substance of the central nervous system; myelinated nervous fibers

________-mature cartilage cell

___________-the bundle of nervous tissue that runs from the brain to the lumbar vertebrae and provides a conduction pathway to and from the brain

_________________________________ -a state of body equilibrium or stable internal environment of the body