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