The cardiac conduction system refers to a group of specialized muscle cells of the heart’s wall (Assadi, 2013). The cells are meant to send signals to the cardiac muscles thus contraction. The major components of the cardiac conduction system are the Atrioventricular node, sinuatrial node, the bundle of His, Purkinje fibers, and the right and left bundle branches (Assadi, 2013). SAN is spindle shaped structure that has fibrous tissue matrix that comprises of closely packed cells and is located near the epicardial surface in the right arterial sulcus …show more content…
Oxygen then diffuses into the red blood cells from the alveoli. The diffusion takes place because the PO2 in the alveoli is higher than that of blood (Pittman, 2011). This creates a pressure gradient that allows oxygen to diffuse into the capillaries in the alveoli. These capillaries have blood that has red blood cells that carries oxygen in two forms: dissolved in plasma and red blood cells water and bound to hemoglobin. The blood carried in hemoglobin accounts for 98%, of all oxygen in blood (Pittman, 2011). The blood cells then infiltrate into the capillaries that supply the tissues. The oxygen then diffuses into the tissue from the hemoglobin leading to partially or fully unloaded hemoglobin often referred to as doxyhemoglibin (Pittman, 2011). The diffusion is enabled by the existence of low oxygen partial pressure in the tissues and high partial pressure of CO2. The CO2 therefore diffuses into the blood cells and oxygen into the tissues. The blood full of CO2 returns to the lungs where it enters the capillaries in the lungs reaching the alveoli and the cycle repeats itself (Pittman, 2011). The oxygenated blood is red in color while the deoxygenated purplish or pale in …show more content…
Prolonged exercise periods translate into physical activity that reduces the left ventricular mass as well as impaired cardiac compliance. This reduces the upright stroke volume and the intolerance to orthostatic (Gielen et al., 2010). The converse is true for individuals who do not exercise regularly. This maintains the normal left ventricle contractile function through prevention of cardiac pathologies that are associated with ageing (Fleg & Strait, 2012). Regular exercise also results into cardiac adaptation thus the athlete’s heart; a physiological cardiac hypertrophy (Gielen et al., 2010). Lastly, this also prevents the impaired systolic and diastolic cardiac function that come with some short term challenges such as ischemia/ reperfusion and doxorubicin (Gielen et al., 2010). All these increase the efficiency of the heart thus its health and well being (Gielen et al., 2010). When the heart is functioning well the blood is able to be pumped throughout the body to meet the various bodily needs. Regular excise reduces the chances of cardiac fatigue that is usually prevalent in those that do not exercise (Fleg & Strait, 2012). Some of the associated cardiac pathologies identified and prevented through exercise are oxidative stress, cardiac fatigue, cardiomyocyte apoptosis, and accumulation of heat shock proteins (Gielen et al., 2010).