The aorta is the main and largest artery in the human body, originating from the left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at the aortic bifurcation into two smaller arteries. The aorta distributes oxygenated blood to all parts of the body through the systemic circulation.
An artery is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body. Most arteries carry oxygenated blood; the two exceptions are the pulmonary and the umbilical arteries, which carry deoxygenated blood to the organs that oxygenate it. The effective arterial blood volume is that extracellular fluid which fills the arterial system.
Blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away from the tissues. Blood vessels are needed to sustain life, because all of the body's tissues rely on their functionality.
Veins are blood vessels in the circulatory system of humans and most other animals that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal circulations which carry oxygenated blood to the heart. In the systemic circulation arteries carry oxygenated blood away from the heart, and veins return deoxygenated blood to the heart, in the deep veins.
The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein that receives venous return from the upper half of the body, above the diaphragm. Venous return from the lower half, below the diaphragm, flows through the inferior vena cava. The SVC is located in the anterior right superior mediastinum. It is the typical site of central venous access via a central venous catheter or a peripherally inserted central catheter. Mentions of "the cava" without further specification usually refer to the SVC.
Vasa vasorum are small blood vessels that comprise a vascular network supplying the walls of large blood vessels, such as elastic arteries and large veins.
The basal lamina is a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits. It is often incorrectly referred to as the basement membrane, though it does constitute a portion of the basement membrane. The basal lamina is visible only with the electron microscope, where it appears as an electron-dense layer that is 20–100 nm thick.
The adventitia is the outer layer of fibrous connective tissue surrounding an organ.
The tunica intima, or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are in direct contact with the blood flow.
In cardiology, the cardiac skeleton, also known as the fibrous skeleton of the heart, is a high-density homogeneous structure of connective tissue that forms and anchors the valves of the heart, and influences the forces exerted by and through them. The cardiac skeleton separates and partitions the atria from the ventricles .The heart's cardiac skeleton comprises four dense connective tissue rings that encircle the mitral and tricuspid atrioventricular (AV) canals and extend to the origins of the pulmonary trunk and aorta. This provides crucial support and structure to the heart while also serving to electrically isolate the atria from the ventricles.
The aortic arch, arch of the aorta, or transverse aortic arch is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea.
The vasa recta of the kidney, are the straight arterioles, and the straight venules of the kidney, – a series of blood vessels in the blood supply of the kidney that enter the medulla as the straight arterioles, and leave the medulla to ascend to the cortex as the straight venules.. They lie parallel to the loop of Henle.
An arterial dissection is a tear within the wall of an artery, which allows blood to separate the wall layers. There are several types. Usually, a tear is in an arterial wall, but a vein wall tear has been documented.
The muscular layer is a region of muscle in many organs in the vertebrate body, adjacent to the submucosa. It is responsible for gut movement such as peristalsis. The Latin, tunica muscularis, may also be used.
The tunica albuginea is the fibrous envelope that extends the length of the corpora cavernosa penis and corpus spongiosum penis. It is a bi-layered structure that includes an outer longitudinal layer and an inner circular layer.
The tunica externa, also known as the tunica adventitia, is the outermost tunica (layer) of a blood vessel, surrounding the tunica media. It is mainly composed of collagen and, in arteries, is supported by external elastic lamina. The collagen serves to anchor the blood vessel to nearby organs, giving it stability.
An elastic artery is an artery with many collagen and elastin filaments in the tunica media, which gives it the ability to stretch in response to each pulse. This elasticity also gives rise to the Windkessel effect, which helps to maintain a relatively constant pressure in the arteries despite the pulsating nature of the blood flow. Elastic arteries include the largest arteries in the body, those closest to the heart. They give rise to medium-sized vessels known as distributing arteries.
The theca externa is the outer layer of the theca folliculi. It is derived from connective tissue, the cells resembling fibroblasts, and contains abundant collagen. During ovulation, the surge in luteinizing hormone increases cAMP which increases progesterone and PGF2α production. The PGF2α induces the contraction of the smooth muscle cells of the theca externa, increasing intrafollicular pressure. This aids in rupture of the mature oocyte, or immature oocyte at the germinal vesicle stage in the canine, along with plasmin and collagenase degradation of the follicle wall.
Muscle is a soft tissue, one of the animal tissues that makes up the three different types of muscle. Muscle tissue gives skeletal muscles the ability to contract. Muscle is formed during embryonic development, in a process known as myogenesis. Muscle tissue contains special contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins present are two regulatory proteins, troponin and tropomyosin.
The internal elastic lamina or internal elastic lamella is a layer of elastic tissue that forms the outermost part of the tunica intima of blood vessels. It separates tunica intima from tunica media.
