Matching Pairs HUMAN BIOLOGYOnline version LINK NAME AND DEFINITION by Guy Kruse 1 muscle tissue 2 organ 3 cells 4 nervous tissue 5 epithelial tissue 6 organ system 7 cardiovascular system 8 hormone 9 tissue 10 connective tissue A chemical messenger molecule. Group of nerve cells that sense stimuli and transmit signals; found in brain, spinal cord, and nerves. Organs that work together to serve a common purpose. Bands of cells that contract and allow movement. Layers of tightly packed cells that line the surfaces of the body. Group of similar cells working together. Structure made of two or more tissues that work together. Group of cells that are all involved in supporting and binding other tissues of the body; i.e. tendon, cartilage, bone, and blood. Organ system made up of the heart, blood, and blood vessels. Basic unit of structure and function of a living organism; the basic unit of life.