______________-a fatty electrical insulator that allows faster and more energetically efficient conduction of impulses Myelin sheath

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

_______________________________________-the seven vertebrae of the vertebral column

________-mature cartilage cell

_______________-an active transport system that simultaneously drives Na+ out of the cell against a steep gradient and pumps K+ back in

_________-system consisting of the skin, hair, nails, and exocrine glands

________________-internal layer of skeletal bone

Identify and click on the diaphragm.

_____________-freely movable joint exhibiting a joint cavity; also called a diarthrosis

_______________-embryonic formation of bone by the replace of calcified cartilage; most skeletal bones are formed by this process