Cells and gene expression programs in the adult human heart

Monika Litvinukova; Carlos Talavera-Lopez; Henrike Maatz; Daniel Reichart; Catherine L. Worth; Eric L. Lindberg; Masatoshi Kanda; Krzysztof Polanski; Eirini S. Fasouli; Sara Samari; Kenny Roberts; Elizabeth Tuck; Matthias Heinig; Daniel DeLaughter; Barbara McDonough; Hiroko Wakimoto; Joshua M. Gorham; Emily Nadelmann; Krishnaa T. Mahbubani; Kourosh Saeb-Parsy; Giannino Patone; Joseph J Boyle; Hongbo Zhang; Hao Zhang; Anissa Viveiros; Gavin Oudit; Omer Bayraktar; J. G. Seidman; Christine Seidman; Michela Noseda; Norbert Hubner; Sarah A. Teichmann

The heart is a complex organ, composed of four morphologically and functionally distinct chambers ( Figure 1A ), that perpetually pumps blood throughout our lives. Deoxygenated blood enters the right atrium and is propelled into the low pressure vascular beds of the lungs by the right ventricle. Oxygenated pulmonary blood enters the left atrium and then to the left ventricle, which propels blood across the body at systemic vascular pressures. Right and left chambers are separated by the atrial and interventricular septa and unidirectional flow is established by the atrio-ventricular valves (tricuspid and mitral) and ventricular-arterial valves (pulmonary and aortic). The heart contains an intrinsic electrophysiologic system, composed of the sinoatrial node in the right atria where depolarization begins and spreads to the atrioventricular node located at the top of the interventricular septum. This electrical impulse is then rapidly propagated by Purkinje fibers to the apex where contraction begins.