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Inferior Mesenteric Artery
In human anatomy, the inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the anal canal. The regions supplied by the IMA are the descending colon, the sigmoid colon, and part of the rectum. Structure Origin The IMA arises from the anterior aspect of the abdominal aorta. Its origin is situated at the L3 vertebral level ( subcostal plane), below the origins of the two renal arteries, 3-4 cm above the aortic bifurcation, at the level of the umbilicus, and posterior to the inferior border of the horizontal (III) part of the duodenum. Branches Along its course, the IMA has the following branches: All these arterial branches further divide into arcades which then supply the colon at regular intervals. Relations The IMA is accompanied along its course by a similarly named vein, the inferior mesenteric vein, which drains into the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmoid Colon
The sigmoid colon (or pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus ''sigma'' + '' -oid''). This part of the colon normally lies within the pelvis, but due to its freedom of movement it is liable to be displaced into the abdominal cavity. Structure The sigmoid colon begins at the superior aperture of the lesser pelvis, where it is continuous with the iliac colon, and passes transversely across the front of the sacrum to the right side of the pelvis. It then curves on itself and turns toward the left to reach the middle line at the level of the third piece of the sacrum, where it bends downward and ends in the rectum. Its function is to expel solid and gaseous waste from the gastrointestinal tract. The curving path it takes toward the anus allows it to store gas in the superior arched portion, enabling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watershed Area (medical)
Watershed area is the medical term referring to regions of the body, that receive dual blood supply from the most distal branches of two large arteries, such as the splenic flexure of the large intestine. The term refers metaphorically to a geological watershed, or drainage divide, which separates adjacent drainage basins. For example, the watershed area of colon includes the griffith point and sudeck’s point. During times of blockage of one of the arteries that supply the watershed area, such as in atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ..., these regions are spared from ischemia by virtue of their dual supply. However, during times of systemic hypoperfusion, such as in disseminated intravascular coagulation or heart failure, these regions are partic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portal Vein
The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approximately 75% of total liver blood flow is through the portal vein, with the remainder coming from the hepatic artery proper. The blood leaves the liver to the heart in the hepatic veins. The portal vein is not a true vein, because it conducts blood to capillary beds in the liver and not directly to the heart. It is a major component of the hepatic portal system, one of three portal venous systems in the human body; the others being the hypophyseal portal system, hypophyseal and Renal portal system, renal portal systems. The portal vein is usually formed by the confluence of the superior mesenteric vein, superior mesenteric, splenic veins, inferior mesenteric vein, inferior mesenteric, left gastric vein, left, right gastric veins and the pancr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splenic Vein
In human anatomy, the splenic vein (formerly the lienal vein) is a blood vessel that drains blood from the spleen, the stomach fundus and part of the pancreas. It is part of the hepatic portal system. Structure The splenic vein is formed from small venules that leave the spleen. It travels above the pancreas, alongside the splenic artery. It collects branches from the stomach and pancreas, and most notably from the large intestine (also drained by the superior mesenteric vein) via the inferior mesenteric vein, which drains in the splenic vein shortly before the origin of the hepatic portal vein. The splenic vein ends in the portal vein, formed when the splenic vein joins the superior mesenteric vein. Clinical significance The splenic vein can be affected by thrombosis, presenting some of the characteristics of portal vein thrombosis and portal hypertension but localized to part of the territory drained by the splenic vein. These include varices in the stomach wall due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Mesenteric Vein
In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV). Structure The inferior mesenteric vein merges with the splenic vein, posterior to the middle of the body of the pancreas. The splenic vein then merges with the superior mesenteric vein to form the portal vein. Tributaries Tributaries of the inferior mesenteric vein drain the large intestine, sigmoid colon and rectum. These include: * left colic vein * sigmoid veins * superior rectal vein * rectosigmoid veins Variation Anatomical variations include the inferior mesenteric vein draining into the confluence of the superior mesenteric vein ''and'' splenic vein and the inferior mesenteric vein draining in the superior mesenteric vein. Clinical significance The inferior mesenteric vein may be damaged during Abdominal surgery, surger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vein
Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards 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. There are three sizes of veins: large, medium, and small. Smaller veins are called venules, and the smallest the post-capillary venules are microscopic that make up the veins of the microcirculation. Veins are often closer to the skin than arteries. Veins have less smooth muscle and connective tissue and wider internal diameters than arteries. Because of their thinner walls and wider lumens they are able to expand and hold more blood. This greater capacity gives them the term of ''capacitance vessels''. At any time, nearly 70% o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colon (anatomy)
The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being removed by defecation. The colon (progressing from the ascending colon to the transverse, the descending and finally the sigmoid colon) is the longest portion of the large intestine, and the terms "large intestine" and "colon" are often used interchangeably, but most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal. In humans, the large intestine begins in the right iliac region of the pelvis, just at or below the waist, where it is joined to the end of the small intestine at the cecum, via the ileocecal valve. It then continues as the colon ascending the abdomen, across the width of the abdominal cavity as the transverse colon, and then desce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arterial Arcades
The arterial arcades (intermesenteric arterial anastomoses or Riolan arcades) are a series of anastomosing arterial arches between the arterial branches of the jejunum and ileum. Nearest the duodenum the mesenteric loops are primary, the vasa recta are long and regular in distribution, and the translucent spaces (lunettes) are extensive. Toward the ileocolic junction, secondary and tertiary loops are observed, the vessels are smaller and become obscured by numerous fat-tabs. The diagrams below show the arrangement and variations of the loops of the mesenteric vessels for various segments of the small intestine of average length: Additional images File:Intestinal arteries.JPG, Arterial arcades File:Arterial arcades.JPG, Arterial arcades File:Gray1065.png, Loop of small intestine showing distribution of intestinal arteries File:Gray1066.png, Loop of small intestine showing distribution of intestinal arteries File:Gray1067.png, Loop of small intestine showing distribution of i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left Colic Artery
The left colic artery is a branch of the inferior mesenteric artery distributed to the descending colon, and left part of the transverse colon. It ends by dividing into an ascending branch and a descending branch; the terminal branches of the two branches go on to form anastomoses with the middle colic artery, and a sigmoid artery (respectively). Structure The left colic artery usually represents the dominant arterial supply to the left colic flexure. Course The left colic artery passes to the left posterior to the peritoneum. After a short but variable course, it divides into an ascending branch and a descending branch. Branches and anastomoses Ascending branch The ascending branch passes superior-ward. It passes anterior to the (ipsilateral) psoas major muscle, gonadal vessels, ureter, and kidney; it passes posterior to the inferior mesenteric vein. Its terminal branches form anastomoses with those of the middle colic artery; it also forms anastomoses with the desc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duodenum
The duodenum is the first section of the small intestine in most vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine. In humans, the duodenum is a hollow jointed tube about long connecting the stomach to the jejunum, the middle part of the small intestine. It begins with the duodenal bulb, and ends at the duodenojejunal flexure marked by the suspensory muscle of duodenum. The duodenum can be divided into four parts: the first (superior), the second (descending), the third (transverse) and the fourth (ascending) parts. Overview The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms ''anterior intestine'' or ''proximal intestine'' may be used instead of duodenum. In mammals the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navel
The navel (clinically known as the umbilicus; : umbilici or umbilicuses; also known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. Structure The umbilicus is used to visually separate the abdomen into quadrants. The umbilicus is a prominent Scar#Umbilical, scar on the abdomen, with its position being relatively consistent among humans. The skin around the waist at the level of the umbilicus is supplied by the tenth thoracic spinal nerve (T10 dermatome (anatomy), dermatome). The umbilicus itself typically lies at a vertical level corresponding to the junction between the L3 and L4 vertebrae, with a normal variation among people between the L3 and L5 vertebrae. Parts of the adult navel include the "umbilical cord remnant" or "umbilical tip", which is the often protruding scar left by the detachment of the umbilical cord. This is located in the center of the navel, sometimes described ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
