tissue
cells
epithelial tissue
organ
connective tissue
muscle tissue
organ system
hormone
nervous tissue
cardiovascular system
A chemical messenger molecule.
Structure made of two or more tissues that work together.
Layers of tightly packed cells that line the surfaces of the body.
Organs that work together to serve a common purpose.
Group of similar cells working together.
Group of nerve cells that sense stimuli and transmit signals; found in brain, spinal cord, and nerves.
Organ system made up of the heart, blood, and blood vessels.
Group of cells that are all involved in supporting and binding other tissues of the body; i.e. tendon, cartilage, bone, and blood.
Bands of cells that contract and allow movement.
Basic unit of structure and function of a living organism; the basic unit of life.
