Coronary Artery Paper

Coronary arteries supply the heart with a constant supply of blood. These arteries are essential, providing oxygen and nutrients that keep the heart constantly pumping. Arteries have three layers including the external layer, tunica external, middle layer, tunica media and the inner layer, called the tunica intima. The outer layer is made up of connective tissue with elastic and collagenous fibers. Tunica media is the thickest layer composed of smooth muscle and can change the diameter of the arteries to control blood flow and pressure. The tunica intima is composed of simple squamous epithelium (Patton & Thibodeau, 2013, 643). There is a left and right coronary artery that “branch from the aorta just superior to the aortic valve. They lie on the epicardium of the hearts surface, encircling the heart in an atrioventricular groove” (Clancy & Andrew, 2009, 310). The
One of the first accommodations the heart makes is through cardiac output. Cardiac output is the amount of blood pumped out of the heart per minute. There are four determinants of cardiac output: heart rate, preload, afterload, and stroke volume. The equation used to calculate cardiac output is (CO = SV (per beat) X HR (per min)). Having a clear understanding between the four components will help with understanding cardiac output (Vincent, 2008, 174). Increased heart rate is one of the simplest measures of increased activity. A way to measure a subject’s heart rate is by counting the beats per minute from the radial or carotid artery. Normal heart rate is about 60 to 80 beats per minute. However, as soon as exercise begins, the heart rate responds in proportion to the exercise intensity until reaching maximal heart rate. Maximal heart rate varies from person to person, therefore to calculate each subject’s specific maximum heart rate, use the formula: 220 minus the age of the