Question

Write 600 words about the jejunum, mention the 4 main layers that make up the tubular part of the GIT and highlight some of the key histological features that contribute to the function of the jejunum.

Answer 1

JEJUNUM

The jejunum is the middle segment of the small intestine located between the duodenum and the ileum. Most of the nutrients present in meals are absorbed with the aid of the jejunum earlier than being surpassed directly to the ileum for in addition absorption.

The jejunum is a continuation of the small gut following the duodenum. It starts at the duodenojejunal flexure, where the small intestine turns sharply closer to the anterior path From the duodenojejunal flexure, the jejunum follows a convoluted path thru the abdomen before continuing as the ileum. While the jejunum does no longer have an anatomical landmark to separate it from the ileum, it slowly changes its anatomical structure along its length as it transitions into the ileum.

Physiology

Partially digested food, referred to as chyme, enters the jejunum from the duodenum. As chyme enters the jejunum, it's miles mixed by way of segmentations, or localized clean muscle contractions within the walls of the jejunum. These segmentations help to circulate chyme and boom its touch with the partitions of the jejunum. The partitions of the jejunum are folded normally over to growth its floor region and permit it to soak up nutrients. Each epithelial cell on the floor of the jejunum consists of microscopic folds of cellular membrane called microvilli that create tiny wallet and growth the touch among the cells and chyme. The entire wall of the jejunum is likewise folded into microscopic finger-like ridges referred to as villi that shape larger wallet and in addition boom the surface location of the jejunum. At the macroscopic level, the internal floor of the jejunum incorporates many wrinkles of tissue known as circular folds, which create even more pockets for chyme and further boom the floor vicinity available for absorption. Thus, the entire structure of the jejunum is optimized for the absorption of nutrients from chyme. By the time chyme has exceeded through the jejunum and enters the ileum, around 90% of all available nutrients were absorbed into the body

Laters of the jejunum are

INNER ----> OUTER

1) MUCOSA

2) SUBMUCOSA

3) MUSCULARIS EXTERNA

4)SEROSA

The innermost layer, the mucosa, surrounds the hollow lumen and affords contact among the jejunum and chyme. It is made from folds of epithelial tissue specialised for absorption of nutrients. Many goblet cells within the mucosa produce mucus to protect the intestinal partitions and to lubricate chyme passing via the jejunum.

Deep to the mucosa is the submucosa layer that supports the opposite tissue layers. Many blood vessels and nerves bypass via the submucosa to offer oxygen, nutrients, and nerve signals to tissues of the jejunum.

The muscularis is the subsequent layer of the jejunum that surrounds the submucosa and contains clean muscle tissue. Contractions of the easy muscle inside the muscularis permit meals to be mixed and propelled through the jejunum. Finally, the serosa the outermost layer of the jejunum and features as the pores and skin of the intestine. Serosa is developed from simple squamous epithelial tissue and secretes a thin slippery liquid referred to as serous fluid. Serous fluid lubricates the outdoors of the jejunum and protects it from friction between organs of the belly cavity

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