License Image The superior vena cava and inferior vena cava (not shown) bring deoxygenated blood from the body into the right atrium, from which it enters the right ventricle. Blood leaves the right ventricle via the pulmonary trunk. The pulmonary trunk delivers deoxygenated blood to the lungs. It splits into the right and left pulmonary […]
License Image This cross section of the heart shows the right ventricle, tricuspid valve, left ventricle, bicuspid (mitral) valve, left atrium, right atrium, superior vena cava, inferior vena cava, aorta, aortic valve, papillary muscle, chordae tendineae, and trabeculae carneae. The heart ventricular walls consist of three layers: the 1.epicardium, the 2.myocardium (cardiac muscle), and the […]
License Image When the heart must work harder to pump blood because of increased systemic vascular resistance, the heart’s left ventricle muscular walls get thicker, such as a biceps muscle will get larger after weight training, This is called left ventricular hypertrophy. The most common cause is high blood pressure or hypertension.
License Image Vascular Resistance The body uses blood vessel diameter as one way to help regulate blood pressure. A normal blood vessel has some degree of smooth muscle contraction (or “tone”) that determines the diameter of the vessel. Nerves controlling the muscle fibers in the media and certain substances in the blood, can cause the […]
License Image The coronary arteries supply oxygen to the heart muscle. When an artery is narrowed by atherosclerotic plaque, the blood flow and therefore, oxygen supply to the heart muscle is decreased, causing myocardial ischemia (angina). If a blood clot or atheroma blocks the artery completely, oxygen is cut off and the area of the […]
License Image The wall of an artery contains 3 layers: the tunica intima, the tunica media, and the tunica externa. The intima is the thinnest layer, only one cell thick, it surrounds the lumen of the blood vessel through which blood flows. The media is usually the thickest containing layers of smooth muscle cells and […]
License Image The main arteries are: aorta Head & Neck: external carotid artery internal carotid artery common carotid artery Arm: subclavian artery brachial artery radial artery ulnar artery Leg: common iliac artery external iliac artery femoral artery popliteal artery anterior tibial artery posterior tibial artery