Search results
Results from the WOW.Com Content Network
The ileum follows the duodenum and jejunum and is separated from the cecum by the ileocecal valve (ICV). In humans, the ileum is about 2–4 m long, and the pH is usually between 7 and 8 (neutral or slightly basic). Ileum is derived from the Greek word εἰλεός (eileós), referring to a medical condition known as ileus. [citation needed]
The ileum: The final section of the small intestine. It is about 3 m long, and contains villi similar to the jejunum. It absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients. The ileum joins to the cecum of the large intestine at the ileocecal junction. [citation needed]
Jejunum: This is the midsection of the small intestine, connecting the duodenum to the ileum. It is about 2.5 m (8.2 ft) long and contains the circular folds also known as plicae circulares and villi that increase its surface area. Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
The cecum receives chyme from the last part of the small intestine, the ileum, and connects to the ascending colon of the large intestine. At this junction there is a sphincter or valve, the ileocecal valve which slows the passage of chyme from the ileum, allowing further digestion. It is also the site of the appendix attachment. [33]
The division between the jejunum and ileum is not anatomically distinct. [5] In adult humans, the small intestine is usually 6–7 m (20–23 ft) long (post mortem), about two-fifths of which (about 2.5 m (8.2 ft)) is the jejunum. [4]
Anatomy figure: 39:05-09 at Human Anatomy Online, SUNY Downstate Medical Center—"The cecum with the distal portion of the ileum." Anatomy photo:39:14-0101 at the SUNY Downstate Medical Center—"Incisions of the Cecum" Cross section image: pelvis/pelvis-e12-2—Plastination Laboratory at the Medical University of Vienna; Photo at mgccc.cc.ms.us
The length of the small intestine can vary greatly, from as short as 2.75 m (9.0 ft) to as long as 10.49 m (34.4 ft). [6] On average it is about 6.1 m (20 ft). [ 1 ] Due to this variation it is recommended that following surgery the amount of bowel remaining be specified rather than the amount removed.
The chyme moves through the jejunum and the ileum, where digestion progresses, and the non-useful portion continues onward into the large intestine. The duodenum is protected by a thick layer of mucus and the neutralizing actions of the sodium bicarbonate and bile. At a pH of 7, the enzymes that were present from the stomach are no longer active.