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