Matching Pairs Tissues, Organs, and Body SystemsOnline version Review the tissue, organ, and body systems. by Janelle Ruiz 1 Respiratory System 2 Muscular System 3 Epithelial Tissue 4 Nervous System 5 Circulatory System 6 Digestive System 7 Connective Tissue Supports organs and joins tissue Lines organs and protects inside of body from outside world Responsible for gas exchange (oxygen- carbon dioxide) with the outside environment Heart, veins, capillaries Brain, spinal column, axons