_________-the basic building block of proteins; made of a central carbon, a carboxyl group,an amino group, and an -R group; only the side group differs in each structure.

______________-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