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Mayazoey
Joined 31 July 2007
→Basic Anatomy and Physiology
== Basic Anatomy and Physiology ==
== Basic Anatomy and Physiology ==
The intestines are a portion of the alimentary tract extending from the pylorus to the anus. In mammals, the intestines are divided into two main segments: the small intestine and the large intestine. The small intestine, which consists of the duodenum, jejunum and ileum is the main site of absorption for digestive products in the gastrointestinal tract. The large intestine, which consists of the caecum and colon, functions to extract water, electrolytes and nutrients as well as to concentrate and propulse faecal material to the rectum for defaecation. (Dyce et. al, 2002; Young & Heath, 2000). Figure or diagram such as on p. 342
The intestines are a portion of the alimentary tract extending from the pylorus to the anus. In mammals, the intestines are divided into two main segments: the small intestine and the large intestine. The small intestine, which consists of the duodenum, jejunum and ileum is the main site of absorption for digestive products in the gastrointestinal tract. The large intestine, which consists of the caecum and colon, functions to extract water, electrolytes and nutrients as well as to concentrate and propulse faecal material to the rectum for defaecation. (Dyce et. al, 2002; Young & Heath, 2000).
Functional differences between the small and large intestine are reflected in their anatomic and histologic organisation. The small intestinal mucosa in many species is highly folded and made up of numerous villi that greatly increase the absorptive surface area. Enterocytes are the most numerous and characteristic cells of the small intestine and act as the main absorptive cells. In contrast, the large intestinal mucosa has no villi and consists of 2 main cell types: absorptive cells and mucus secreting goblet cells. A distinguishing histological and anatomical feature of the large intestine is the thick muscularis mucosa layer.
=== Cell types ===
=== Defense Mechanisms ===
=== Defense Mechanisms ===
==== Secretions ====
==== Secretions ====