American flamingo pace is maintained by pacemaker cells found in the sinoatrial node, located on the right atrium. The sinoatrial node uses calcium to cause a depolarizing signal transduction pathway from the atrium through right and left atrioventricular bundle which communicates contraction to the ventricles. The avian heart also consists of muscular arches that are made up of thick bundles of muscular layers. Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers. The atrium walls tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood throughout
Sentinel node list, can be simplified remarkably using a sentinel node to demarcate the beginning and end of the list. Following is a Python implementation of a circular doubly-linked list: Notice how the codice_13 method takes the node that will be displaced by the new node in the parameter codice_14. For appending to the left, this is the head of a non-empty list, while for appending to right, it is the tail. But because of how the linkage is setup to refer back to the sentinel, the code just works for empty lists as well, where codice_14 will be the sentinel node.