Biology

                        In the thoracic cavity, lies between the lungs, behind the breast bone Structure fist-sized layers:   pericardium – tough protective sac heart muscle - myocardium endocardium -> valves cardiac muscle:   never gets tired (doesn’t…

About 5 litres pH 7.4 Function: Transports respiratory gases nutrients waste materials hormones enzymes regulates body temperature pH protects against blood loss foreign agents   Blood components: Blood plasma 55% Cellular elements…