The alimentary canal as a biotope

It is not intended to give here a detailed description of the vertebrate alimentary canal, accounts of which are given in the reviews referred to above. Some parameters of the intestinal environment which are likely to be important for the establishment and growth of a cestode are shown in Fig. 3.1. It is important to appreciate, however, that the physiology of a 

Increased levels of myeloperoxidase and phospholipase Increased levels of histamine, 5-HT, leukotrienes, prostaglandins 

The basic cytology and ultrastructure, physiology and biochemistry of the mucosa, has been reviewed in detail by Henry (318) and Nugent O Connor (602). This topic can be considered broadly under four headings. 

Only (a)-(c) are likely to be important in relation to cestode attachment and growth and are considered further below. 

The morphology of the villi in man shows some variation between different races but also varies according to anatomic location, those villi in the jejunum being more regular than those in the duodenum. The most numerous cells of the villous epithelium are the columnar absorptive cell or enterocyte (Fig. 3.2) and the goblet cell (considered later). The amplification 

---