- Biology of the Blood Vessels
- Cross-Section of Artery and Vein
- Morphometric assessment of the central retinal artery and vein in the optic nerve head.
- Physiology of Circulation
Biology of the Blood Vessels
Histology of arteries, veins and capillaries (preview) - Microscopic Anatomy - Kenhuband your can grove city center for dentistry
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. The arteries are part of the circulatory system , which is responsible for the delivery of oxygen and nutrients to all cells, as well as the removal of carbon dioxide and waste products, the maintenance of optimum blood pH , and the circulation of proteins and cells of the immune system. The anatomy of arteries can be separated into gross anatomy , at the macroscopic level , and microanatomy , which must be studied with a microscope. The arterial system of the human body is divided into systemic arteries , carrying blood from the heart to the whole body, and pulmonary arteries , carrying deoxygenated blood from the heart to the lungs. The outermost layer of an artery or vein is known as the tunica externa , also known as tunica adventitia , and is composed of collagen fibers and elastic tissue - with the largest arteries containing vasa vasorum small blood vessels that supply large blood vessels .
The primary pulmonary circulation comprising of the pulmonary arterial tree, extensive capillary bed and pulmonary venous tree, connected in series is a low pressure, high capacitance system which provides large surface area for gas exchange. The bronchial circulation which provides nutrients to the lungs is a low capacitance, high pressure system and normally does not participate in blood oxygenation. The main pulmonary artery arises from the right ventricular outflow tract and courses posteriorly and superiorly to the left of and posterior to the aorta 1. Below the aortic arch, it bifurcates into right and left main pulmonary arteries at the level of the carina. The right and left pulmonary arteries divide into 2 lobar branches each, and subsequently into segmental and sub segmental branches. Segmental and sub segmental pulmonary arteries generally parallel segmental and sub segmental bronchi and are named according to the bronchopulmonary segments that they feed Figure 1. The bronchopulmonary segment is a functionally and anatomically discrete portion of lung supplied by its own segmental bronchus and artery.
In addition to forming the connection between the arteries and veins , capillaries have a vital role in the exchange of gases, nutrients, and metabolic waste products between the blood and the tissue cells. Substances pass through the capillary wall by diffusion , filtration, and osmosis. Oxygen and carbon dioxide move across the capillary wall by diffusion. Fluid movement across a capillary wall is determined by a combination of hydrostatic and osmotic pressure. The net result of the capillary microcirculation created by hydrostatic and osmotic pressure is that substances leave the blood at one end of the capillary and return at the other end.
The heart and blood vessels constitute the cardiovascular circulatory system. The blood circulating in this system delivers oxygen and nutrients to the tissues of the body and removes waste products from the tissues. Blood travels from the heart in arteries, which branch into smaller and smaller vessels, eventually becoming arterioles. Arterioles connect with even smaller blood vessels called capillaries. Through the thin walls of the capillaries, oxygen and nutrients pass from blood into tissues, and waste products pass from tissues into blood.
Cross-Section of Artery and Vein
Arteries and veins have the same layers of tissues in their walls, but the proportions of these layers differ. Lining the core of each is a thin layer of endothelium, and covering each is a sheath of connective tissue, but an artery has thick intermediate layers of elastic and muscular fiber while in the vein, these are much thinner and less developed.
Morphometric assessment of the central retinal artery and vein in the optic nerve head.
Some features may be unavailable. Meticulous detail makes this the best 3D heart model ever created. Strip back the layers of the heart and hide or fade individual structures to examine every part. View the heart in action like never before. Set the heart rate to simulate real scenarios, or control the animation to examine every minute movement.
Blood is carried through the body via blood vessels. An artery is a blood vessel that carries blood away from the heart, where it branches into ever-smaller vessels. Eventually, the smallest arteries, vessels called arterioles, further branch into tiny capillaries, where nutrients and wastes are exchanged, and then combine with other vessels that exit capillaries to form venules, small blood vessels that carry blood to a vein, a larger blood vessel that returns blood to the heart. Arteries and veins transport blood in two distinct circuits: the systemic circuit and the pulmonary circuit Figure 1. The blood returned to the heart through systemic veins has less oxygen, since much of the oxygen carried by the arteries has been delivered to the cells. In contrast, in the pulmonary circuit, arteries carry blood low in oxygen exclusively to the lungs for gas exchange.
Physiology of Circulation