The small intestine, which is 670 to 760 cm (22 to 25 feet) in length and 3 to 4 cm (about 2 inches) in diameter, is the longest part of the digestive tract. It begins at the pylorus, the juncture with the stomach, and ends at the ileocecal valve, the juncture with the colon. The main functional segments of the small intestine are the duodenum, the jejunum, and the ileum. Show The duodenum is 23 to 28 cm (9 to 11 inches) long and forms a C-shaped curve that encircles the head of the pancreas. Unlike the rest of the small intestine, it is retroperitoneal (that is, it is behind the peritoneum, the membrane lining the abdominal wall). Its first segment, known as the duodenal bulb, is the widest part of the small intestine. It is horizontal, passing backward and to the right from the pylorus, and lies somewhat behind the wide end of the gallbladder. The second part of the duodenum runs vertically downward in front of the hilum of the right kidney (the point of entrance or exit for blood vessels, nerves, and the ureters); it is into this part through the duodenal papilla (papilla of Vater) that the pancreatic juice and bile flow. The third part of the duodenum runs horizontally to the left in front of the aorta and the inferior vena cava (the principal channel for return to the heart of venous blood from the lower part of the body and the legs), while the fourth part ascends to the left side of the second lumbar vertebra (at the level of the small of the back), then bends sharply downward and forward to join the second part of the small intestine, the jejunum. An acute angle, called the duodenojejunal flexure, is formed by the suspension of this part of the small intestine by the ligament of Treitz. The jejunum forms the upper two-fifths of the rest of the small intestine; it, like the ileum, has numerous convolutions and is attached to the posterior abdominal wall by the mesentery, an extensive fold of serous-secreting membrane. The ileum is the remaining three-fifths of the small intestine, though there is no absolute point at which the jejunum ends and the ileum begins. In broad terms, the jejunum occupies the upper and left part of the abdomen below the subcostal plane (that is, at the level of the 10th rib), while the ileum is located in the lower and right part. At its termination the ileum opens into the large intestine. The arrangement of the muscular coats of the small intestine is uniform throughout the length of the organ. The inner, circular layer is thicker than the outer, longitudinal layer. The outermost layer of the small intestine is lined by the peritoneum. Blood and nerve supplyConsider whether the continuous band of membranous tissue around humans' intestines should be deemed an organ See all videos for this articleThe superior mesenteric artery (a branch of the abdominal aorta) and the superior pancreaticduodenal artery (a branch of the hepatic artery) supply the small intestine with blood. These vessels run between layers of the mesentery, the membrane that connects the intestines with the wall of the abdominal cavity, and give off large branches that form a row of connecting arches from which branches arise to enter the wall of the small bowel. The blood from the intestine is returned by means of the superior mesenteric vein, which, with the splenic vein, forms the portal vein, which drains into the liver. The small intestine has both sympathetic and parasympathetic innervation. The vagus nerve provides parasympathetic innervation. Sympathetic innervation is provided by branches from the superior mesenteric plexus, a nerve network underneath the solar plexus that follows the blood vessels into the small intestine and finally terminates in the Auerbach plexus, which is located between the circular and longitudinal muscle coats, and the Meissner plexus, which is located in the submucosa. Numerous fibrils, both adrenergic (sympathetic) and cholinergic (parasympathetic), connect these two plexuses. The intestines are a long, continuous tube running from the stomach to the anus. Most absorption of nutrients and water happen in the intestines. The intestines include the small intestine, large intestine, and rectum. The small intestine (small bowel) is about 20 feet long and about an inch in diameter. Its job is to absorb most of the nutrients from what we eat and drink. Velvety tissue lines the small intestine, which is divided into the duodenum, jejunum, and ileum. The large intestine (colon or large bowel) is about 5 feet long and about 3 inches in diameter. The colon absorbs water from wastes, creating stool. As stool enters the rectum, nerves there create the urge to defecate. Intestine Conditions
SOURCES https://books.google.com/books?id=sOrK6q5ith4C&pg=PA5&lpg=PA5&dq=diameter+of+the+lumen+of+the+intestines&source=bl&ots=-UcZRv0XvX&sig=VhBWzNv9XI8bKKl0pjn0QZo-VH0&hl=en&ei=uvZLSo-DNeDJtgep7vWqDQ&sa=X&oi=book_result&ct=result&resnum=4 Herliner, H., Maglinte, D., Birnbaum, B., and Balthazar, E. Clinical Imaging of the Small Intestine, Springer, Nov. 30, 2001. The Physics Factbook web site: "Length of a Human Intestine." Dummies.com: "Running Through the Human Digestive System." National Cancer Institute: "Small Intestine Cancer," "Colon and Rectal Cancer." National Digestive Diseases Information Clearinghouse: "Celiac Disease," "Colonoscopy," "Flexible Sigmoidoscopy," "Diverticulosis and Diverticulitis." How long are your intestines if stretched out?Research suggests that the combined length of the small and large intestines is at least 15 ft in length. The small intestine can measure about 9–16 ft, while the large intestine is roughly 5 ft long. The intestines have the important role of helping break down and absorb nutrients from food and drink.
How long is a human large and small intestine?Together your small and large intestines are about 15 feet or more in length. According to a 2014 study , the total surface area of your intestines is about half the size of a badminton court. Your intestines have the very important job of helping to break down and absorb nutrients from what you eat and drink.
How long is the small intestine if stretched out?In humans, the small intestine is about 6 meters or 20 feet long and the large intestine is about 1.5 meters or 5 feet long.
What is the real length of small intestine?How long is the small intestine? The small intestine is by far the longest section of the gastrointestinal tract, about 22 feet long. The lining also has a vast surface area that's scrunched into folds and peaks.
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