The section of the small intestine between the duodenum and the ileum.
[Middle English, from Medieval Latin iēiūnum (intestīnum), fasting (intestine) (so called because in dissection it was always found empty), neuter of Latin iēiūnus.]
jejunum
Dictionary:
je·ju·num (jə-jū'nəm)  |
n., pl., -na (-nə).
The section of the small intestine between the duodenum and the ileum.
The section of the small intestine between the duodenum and the ileum.
| 5min Related Video: jejunum |
| World of the Body: jejunum |
The part of the small intestine next beyond the duodenum, and leading to the ileum. Its lining has an enormous surface area, by virtue of folds, projections (villi), and microvilli on the villi. Enzyme secretion and digestion, started in the stomach, continue here, and absorption of the products begins — of glucose and amino acids into blood capillaries and of fats into lymph capillaries (lacteals).
— Stuart Judge
See alimentary system.
| Food and Nutrition: jejunum |
Part of the small intestine, between the duodenum and the ileum; see gastro-intestinal tract.
| Dental Dictionary: jejunum |
n
The middle or intermediate of the three portions of the small intestine, connecting proximally with the duodenum and distally with the ileum. The jejunum has a slightly larger diameter, a deeper color, and a thicker wall than the ileum, and it contains heavy, circular folds that are absent in the lower part of the ileum.
| Veterinary Dictionary: jejunum |
That part of the small intestine extending from the duodenum to the ileum.
| Wikipedia: Jejunum |
| Jejunum | |
|---|---|
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| Small intestine | |
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| Superior and inferior duodenal fossæ. | |
| Gray's | subject #248 1170 |
| Artery | jejunal arteries |
| Vein | jejunal veins |
| Nerve | celiac ganglia, vagus [1] |
| Precursor | midgut |
| MeSH | Jejunum |
| Dorlands/Elsevier | Jejunum |
The jejunum is the middle 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 middle intestine or mid-gut may be used instead of jejunum.[2]
The jejunum lies between the duodenum and the ileum. The change from the duodenum to the jejunum is usually defined as the ligament of Treitz.
In adult humans, the small intestine is usually between 5.5-6m long, 2.5m of which is the jejunum.
The pH in the jejunum is usually between 7 and 8 (neutral or slightly alkaline).
The jejunum and the ileum are suspended by mesentery which gives the bowel great mobility within the abdomen. It also is wrapped by smooth muscle that helps to move food along by a process known as peristalsis.
Contents |
Internal structure
The inner surface of the jejunum, its mucous membrane, is covered in projections called villi, which increase the surface area of tissue available to absorb nutrients from the gut contents. The epithelial cells which line these villi possess even larger numbers of microvilli. The transport of nutrients across epithelial cells through the jejunum and ileum includes the passive transport of sugar fructose and the active transport of amino acids, small peptides, vitamins, and most glucose. The villi in the jejunum are much longer than in the duodenum or ileum.
The jejunum contains very few Brunner's glands (found in the duodenum) or Peyer's patches (found in the ileum). Instead, it has many large circular folds in its submucosa called plicae circulares which increase the surface area for nutrient absorption.
Etymology
Jejunum is derived from the adjective jejune, which means "fasting" or "hungry" in Early Modern English. It was so called because this portion of the intestine was found "empty" following death.[citation needed][Latin: jejunus, fasting; barren]
Additional images
 Duodenojejunal fossa. |
 Transmission electron microscope (TEM) of Human Jejunum |
 TEM of Mouse Jejunum x14000 |
References
- ^ Physiology at MCG 6/6ch2/s6ch2_30
- ^ Guillaume, Jean; Praxis Publishing, Sadasivam Kaushik, Pierre Bergot, Robert Metailler (2001). Nutrition and Feeding of Fish and Crustaceans. Springer. p. 31. ISBN 1852332417, 9781852332419. http://books.google.ca/books?id=As0flTZo_EAC&pg=PA31&lpg=PA31&dq=fish+cytology+jejunum+duodenum&source=web&ots=VIP6JtTU26&sig=3pt3XfiCKfEKZZ-tFmzpHD_90Cw&hl=en&sa=X&oi=book_result&resnum=4&ct=result#PPA31,M1. Retrieved 2009-01-09.
External links
- Gastrolab.net:The Jejunum
- Peyer's patches
- SUNY Labs 37:11-0100 - "Abdominal Cavity: The Jejunum and the Ileum"
- SUNY Anatomy Image 7856
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| Translations: Jejunum |
Dansk (Danish)
n. - hungertarm, fastetarm
Nederlands (Dutch)
nuchtere darm
Français (French)
n. - (Anat) jéjunum
Deutsch (German)
n. - Leerdarm
Ελληνική (Greek)
n. - (ανατ.) νήστις
Português (Portuguese)
n. - jejuno (m) (Anat.)
Svenska (Swedish)
n. - övre delen av tunntarmen, jejunum
中文（简体）(Chinese (Simplified))
空肠
中文（繁體）(Chinese (Traditional))
n. - 空腸
العربيه (Arabic)
(الاسم) معي صائم, الصائم
עברית (Hebrew)
n. - המעי הריק
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| World of the Body. The Oxford Companion to the Body. Copyright © 2001, 2003 by Oxford University Press. All rights reserved. Read more |
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| Food and Nutrition. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved. Read more |
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| Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved. Read more |
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| Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Jejunum". Read more |
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| Translations. Copyright © 2007, WizCom Technologies Ltd. All rights reserved. Read more |
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