A special characteristic of the heart is its ability to self excite itself. The heart is self excitable because of gap junctions and the composition and structure of the intrinsic cardiac condition system. Noncontractile cardiac …show more content…
The electrocardiography allows an administer to record the cardiac conduction cycle via graph. The graph is composed of three labels referred to as waves that identify conduction. The labels are P wave, QRS complex, and T wave. The P wave indicates the atrial depolarization. The time span of the P wave is about 0.08 seconds and is caused by depolarization wave actions from the SA node to the atria. Shortly after the P wave starts, the atria recoils. The QRS complex is a sign of ventricle depolarization. The average time span of the QRZ complex is about 0.08. After ventricular depolarization happens, ventricular contraction takes place. The T wave depicts ventricular repolarization. Ventricular repolarization averages a time span of 0.6 seconds. Repoloization takes more time than depolarization, resulting in a shorter and wider depiction on the graph. The ECG helps one visualize the mechanical functions of the heart, but understanding the the mechanics themselves of a ECG is even more …show more content…
The movements of the heart are caused by the heart pumping blood out of its chambers, referred to as systole, and the relaxation period of the heart allowing blood to refill its chambers, referred to as diastole. The cardiac cycle explains the actions that take place in the heart during a heart beat. The steps of the cardiac cycle are; Ventricular filling, Ventricular systole, and Isovolumetric relaxation. The cycle starts during the time of relaxation of the heart. During mid-to-late diastole, blood fills the ventricles while the atria recoils. During this time, the heart has a low pressure and 80% and blood from the body circulatory system is fills the area. As the atria relax, ventricular systole proceeds and isovolumetric contraction phase and the ventricular ejection takes place. Isovolumetric is a time period where the blood volume of ventricular chambers is constant due to closing of the chambers. This causes a fast and sharp increase in pressure. When ventricular pressures surpass the pressure of the larger arteries, the SL valves are forces open and blood floods into the aorta and pulmonary trunk. Once ventricular ejection phase takes place, pressure in the aorta usually peaks around 120mm HG. Following these actions, Isovolumetric relaxation takes place, restarting the process over again. The result of the heart being filled with blood and pumping blood out is cardiac output. Many conclusions about the