Heart & Blood Vessels Anatomy PDF

First year, Second semester, Anatomy subject.((6)) Heart & blood vessels. Scientific name is Myocardium. Shape: triangle, broad at the superior surface and tapering to the apex. The heart is made up of four chambers: two upper chambers known as the left atrium and right atrium and two...

First year, Second semester, Anatomy subject.((6)) Heart & blood vessels. Scientific name is Myocardium. Shape: triangle, broad at the superior surface and tapering to the apex. The heart is made up of four chambers: two upper chambers known as the left atrium and right atrium and two lower chambers called the left and right ventricles. It is also made up of four valves: the tricuspid, pulmonary, mitral and aortic valves.  Layers of heart: The wall of the heart separates into the three layers: 1. epicardium, 2. myocardium, and 3- endocardium. These three layers of the heart are embryologically equivalent to the three layers of blood vessels: 1-tunica adventitia, 2-tunica media, and 3- tunica intima. Coronary arteries are the arterial blood vessels of coronary circulation. Coronary arteries are named as such due to the way they encircle the heart, much like a crown. Its arteries originated from root of aorta wrap around the entire heart, which transport oxygenated blood to the heart muscle, are the left coronary artery and right coronary artery.  The two main coronary arteries: 1- Left coronary arteries,(LMCA). Supplies blood to left heart muscle (left ventricle and left atrium). 2- Right coronary artery (RCA). Supply right side, S.A, node , AV node, and bundle of heart between ventricle. The left coronary artery (LCA) initially branches to yield the left anterior descending (LAD), also called the anterior interventricular artery. The LCA also gives off the left marginal artery (LMA) and the left circumflex artery (Cx). In ~20-25% of individuals, the left circumflex artery contributes to the posterior interventricular artery (PIv). The right coronary artery (RCA) branches to form the right marginal artery (RMA) anteriorly. In 80-85% of individuals, it also branches into the posterior interventricular artery (PIv) posteriorly. Heart size: heart length, width, and thickness are (12 cm), (8.5 cm), and (6cm)., the mean weight of the heart is 280-340 g in males and 230-280 g in female. Heart function: pumps blood throughout body by heart muscle contraction, controls heart rate and maintains blood pressure by signal electrical produce via autogenerating in right atrium SA node. The SA node special groups of cells called nodes, other name (sinus node). is a specialized myocardial structure that initiates the electrical impulses to stimulate contraction, and is found in the atrial wall at the junction of superior caval vein and the right atrium. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The heart rate depends on the rate at which the sinoatrial node produces action potentials. At rest, heart rate is between 60 and 100 beats per minute. There are five types of blood vessels: the arteries, which carry the blood away from the heart; the arterioles; the capillaries, where the exchange of water and chemicals between the blood and the tissues occurs; the venules; and the veins, which carry blood from the capillaries back towards the heart. The circulatory system is divided into two separate loops: The shorter pulmonary circuit that exchanges blood between the heart and the lungs for oxygenation; and the longer systemic circuit that distributes blood throughout all other systems and tissues of the body. Both of these circuits begin and end in the heart. Arteries, veins, capillaries Heart -> arteries -> arterioles -> capillaries [gas exchange - oxygenated blood becomes deoxygenated] -> venules -> veins -> heart Pulmonary - superior and inferior vena cava (with deoxygenated blood) -> right atrium -> right ventricle -> right and left pulmonary artery -> capillaries of each lung (oxygenation of the blood) -> pulmonary veins -> left atrium -> systemic circulation Systemic - left atrium -> left ventricle -> aorta and all of its branches -> capillaries -> veins -> superior and inferior vena cava -> pulmonary circulation Coronary - ascending aorta -> right coronary artery -> right marginal branch, posterior interventricular artery, left coronary artery -> anterior interventricular branch (anastomoses with the posterior branch), circumflex artery.