Cardiac Cycle Research Paper
Describe the Cardiac Cycle
The Cardiac cycle is a description of the activities that take place in the period from the start of one heart the next. The conducting system autonomically controls the heart beat impulses it is also called the cardiac conduction system or the nodal system. It is made up of six main components the sinoatrial node (SA-Node), internodal paths, atrioventricular node (AV-Node), atrioventricular bundle (AV bundle) or bundle of His, bundle branches and Purkinje fibres. Contractile cells make up about ninety nine percent of the cardiac muscle tissue on the walls of the aria and ventricles of the heart. The conducting cycle begins at the (SA-Node) when the Vagus nerve stimulates an action potential in the sinoatrial node. …show more content…
Stimuli such as exercise, stimulant drugs, or hormones can change the rate of the SA-Node. The SA-Node is attached to the upper posterior wall of the right atrium near the superior vena cava. The SA-Node has specialized muscle cells which generate spontaneous action potentials which takes about fifty milliseconds to spread to the atria-ventricular node, or AV node. These electrical impulses are generated at the SA-Node one hundred to one hundred and ten per minute. After fifty milliseconds when the action potential moves through the atria surface via the internodal pathways to reach the AV node. During the transition of the action potential moving through the internodal path conducting cells stimulate the contractile cells of the …show more content…
The amount of blood ejected from the ventricles is called the Stroke Volume (SV) this volume is usually between 70 to 80 ml. This movement is created by the relative pressure differences between the semi-lunar valves and the high pressure level that was generated in the ventricles. This is when both the ventricles contract to deliver the blood into the pulmonary and systemic circulation by the shortening of muscle cells. After a duration of about 150 msec when ventricle contraction reaches a peak the ventricular pressure starts decreasing quickly. During this time the semi-lunar valves are shut due to blood from the aorta and pulmonary trunk flowing back into the ventricles. As the pressure in the semi-lunar valves increase they are closed and the amount of blood left in the ventricles at this point is about 50 ml. This volume is called the end-systole volume (ESV). Also during all this time the relaxed atria have been slowly filling passively through venous return from the lungs therefore increasing there
The Cardiac cycle is a description of the activities that take place in the period from the start of one heart the next. The conducting system autonomically controls the heart beat impulses it is also called the cardiac conduction system or the nodal system. It is made up of six main components the sinoatrial node (SA-Node), internodal paths, atrioventricular node (AV-Node), atrioventricular bundle (AV bundle) or bundle of His, bundle branches and Purkinje fibres. Contractile cells make up about ninety nine percent of the cardiac muscle tissue on the walls of the aria and ventricles of the heart. The conducting cycle begins at the (SA-Node) when the Vagus nerve stimulates an action potential in the sinoatrial node. …show more content…
Stimuli such as exercise, stimulant drugs, or hormones can change the rate of the SA-Node. The SA-Node is attached to the upper posterior wall of the right atrium near the superior vena cava. The SA-Node has specialized muscle cells which generate spontaneous action potentials which takes about fifty milliseconds to spread to the atria-ventricular node, or AV node. These electrical impulses are generated at the SA-Node one hundred to one hundred and ten per minute. After fifty milliseconds when the action potential moves through the atria surface via the internodal pathways to reach the AV node. During the transition of the action potential moving through the internodal path conducting cells stimulate the contractile cells of the …show more content…
The amount of blood ejected from the ventricles is called the Stroke Volume (SV) this volume is usually between 70 to 80 ml. This movement is created by the relative pressure differences between the semi-lunar valves and the high pressure level that was generated in the ventricles. This is when both the ventricles contract to deliver the blood into the pulmonary and systemic circulation by the shortening of muscle cells. After a duration of about 150 msec when ventricle contraction reaches a peak the ventricular pressure starts decreasing quickly. During this time the semi-lunar valves are shut due to blood from the aorta and pulmonary trunk flowing back into the ventricles. As the pressure in the semi-lunar valves increase they are closed and the amount of blood left in the ventricles at this point is about 50 ml. This volume is called the end-systole volume (ESV). Also during all this time the relaxed atria have been slowly filling passively through venous return from the lungs therefore increasing there