walls of atria {Ans: are thin}myocardium function {Ans: pump blood throughout body to deliver nutrients}Where does hematopoiesis take place in adults? {Ans: red bone marrow}extrinsic pathway involves {Ans: factor 5 and calcium}pericardial fluid {Ans: resides within the pericardium acts to reduce friction as the heart beats}osmolarity {Ans: dissolved particles in the blood that cannot pass through the blood vessel wall}