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