Small intestine villi

FIGURE 36.9 (a) Synthetic AZA-1 (24 h) injured the liver and the small intestine. Erosion still be seen after 24 h (i), and characteristic change of late recovery at empty lamina propria can be seen in (ii). (b) Isomer injured the liver but ballooning hepatocytes appeared at central area, and did not injure small intestinal villi. 

Guo HL, Wolfe D, Epperly MW et al. (2003) Gene transfer of human manganese superoxide dismutase protects small intestinal villi from radiation injury. J Gastrointest Surg 7 229-235 discussion 235-236... 

Fig. 4 Diagrammatic sketch of the small intestine illustrating the projection of the villi into the lumen (left) and the anatomic features of a single villus (right). (Modified from Ref. 7.)...

Fihn, B. M., A. Sjoqvist, and M. Jodal. Permeability of the rat small intestinal epithelium along the villus-crypt axis effects of glucose transport, Gastroenterology 2000, 119, 1029-1036... 

The inner surface of the small intestine is not smooth and flat but wrinkled into a large number of finger-like projections called villi, which project into the lumen. If we look at each villus under the microscope (Fig. 1) we find it, in turn, has small fingerlike processes projecting out into the lumen - the microvilli. The result of this is that the surface of the small intestine (which is only 300 cm in length - in the relaxed state after death it may measure 6-7 metres), is estimated to have an area of 250 m. It is obviously designed to absorb, particularly, nutrients and this is also where most of any drug taken by mouth is absorbed. 

Epithelial cells of small intestine were prepared in a fractional way (4), the older, less adherent villus tip cells being washed out by EDTA-containing phosphate buffer first, while mitotic crypt cells appeared in the final fractions. The enzyme characteristics of the series of fractions obtained (Fig. 13) followed conventional criteria for differentiated (villus) and less differentiated (crypt) cells (3, 4). The thymidine kinase activity decreased from crypt to villus while the activity of alkaline phosphatase increased (Fig. 13). 

The large internal surface area of the small intestine is attributable to its length, folding, and the presence of villi and microvilli within its lumen. The villi contain capillaries and protrude into the lumen of the small intestine. There are approximately four to five million villi in the small intestine. Each villus has many microvilli as its outer surface (Figure 11.3). The microvilli represent the absorptive barrier of the small intestine. The stomach and large intestine do not contain villi and, therefore, have a small absorptive surface area compared with the small intestine. 

Multidrug resistance- associated protein 2 (MRP2) 190 1545 aa 2 NBD 17 TMD Hydrophihc compounds and conjugates Villus cells, small intestine (BBM), decreasing jejunum to ileum... 

Zinc homeostasis is largely regulated by its uptake and loss through the small intestine. Although a number of zinc transporters and binding proteins have been identified in villus epithehal cells, a full understanding of zinc absorption is not yet at hand. 

Fet5p and hephaestin are type 1 membrane proteins both are found associated with vesicular compartments. Fet5p is localized to the vacuolar membrane in Sa. cerevisiae while hephaestin appears to be associated with a vesicular compartment within the villus cells of the small intestine. These two (apparent) ferroxidases share another similarity neither is... 

Ciypt and Villus Structures of the Mucosa of the Small Intestine... 

The mucosal layer, comprising the lumenal surface of the small intestine, is responsible for the digestive and absorptive functions of the small intestine. The mucosal surface area is much larger than predicted for a simple cylinder. Circular folds account for this amplification. The mucosal surface area is extended further by fingerlike projections called villi and depressions called crypts. The villi are 0.5-1.0 mm in height. Each villus and crypt is lined by epithelial cells that are covered with many closely packed microvilli that project into the intestinal lumen. If the small intestine is viewed as a simple cylinder, its mucosal surface area would be on the order of half of a square meter. However, in reality, the mucosal surface area of the small intestine is approximately 250 square meters, comparable with size of a tennis court. 

Villus absorptive cells in fetal small intestine of man Convoluted membrane - [1571... 

Figure 12.2 Cross section of a villus in the human mucosa of the small intestine.

Rotaviruses are double-stranded wheel-shaped RNA viruses. These strains cause diarrhea by infecting the enterocyts of the villi in the small intestine. Changes to the villi include shortening of villus height, crypt hyperplasia, and mononuclear cell infiltration of the lamina propria. Diarrhea results from decreased absorption across intestinal mucosal surface. ... 

Kilshaw, P.J. H. Slade. Villus atrophy and crypt elongation in the small intestine of preruminant calves fed with heated soyabean flour or wheat gluten. Res. Vet. Sci. 1982, 33, 305—308. 

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