sinoatrial node molecular composition trait sinoatrial node ribonucleic acid amount 2024-04-15T13:34:29Z CMO:0003985 SA node RNA amount SA node ribonucleic acid amount The proportion, quantity, or volume of ribonucleic acid in the small mass of modified cardiac muscle fibers located at the junction of the superior vena cava and the right atrium that is the source of contraction impulses for the heart. Ribonucleic acid is a high molecular weight, linear polymer composed of nucleotides containing ribose and linked by phosphodiester bonds. Trait.ontology VT:0011113 caripark pacemaker RNA amount pacemaker ribonucleic acid amount sinoatrial node RNA amount