Mucosa of the small intestine

The mucosa of the small intestine can be divided into three distinct layers. The muscularis mucosa, the deepest layer, consists of a thin sheet of smooth muscle... 

JL Madara, JS Trier. Functional morphology of the mucosa of the small intestine. In LR Johnson, ed. Physiology of the Gastrointestinal Tract. 2nd ed. New York Raven, 1994. 

Severe anorexia, diarrhea, and melena. Significant histopathology of mucosa of the small intestine. PCB residues, in mg/kg FW, were 139 in fat and 16 in liver No adverse effects on reproduction... 

Most published examples of prodrugs of relevance in the present context contain an a-amino acyl moiety. A number of reasons may explain this fact, such as the lack of toxicity of these natural compounds, the large differences in lipophilicity and other properties between amino acids, and the variability afforded by A-substituents. Interesting examples are provided by salicylic acid and metronidazole. Thus, the hydrolysis of tyrosine and methionine prodrugs of salicylic acid (8.104 and 8.105, respectively) was examined in rabbits after intraduodenal and intracecal administration [134], The former ester, but not the latter, was hydrolyzed in the mucosa of the small intestine. In addition, both prodrugs underwent marked hydrolysis by intestinal microflora. 

Whipple s disease is a rare malabsorption syndrome, which usually occurs in men aged 30-60 years of age. It is caused by a bacterium, Tropheryma whippelii, which infiltrates the mucosa of the small intestine. The symptoms are characterised by arthritis, steatorrhea, weight loss, abdominal pain, fever and weakness. Treatment consists of prolonged administration of antibacterial drugs and the correction of nutritional deficiencies. 

Doherty MM, Charman WN. The mucosa of the small intestine how clinically relevant as an organ of drug metabolism Clin Pharmacokinet 2002 41(4) ... 

Minute amounts of the acid phosphomonoesterases have also been found to occur in the pancreas, in skeletal and heart muscle, and in the mucosa of the small intestines. 

Taeniid cestodes have a prey-predator life cycle involving two mammalian hosts. The definitive host is a carnivore or omnivore, which harbours the adult tapeworm parasite in the small intestine. Mature infective eggs are released with the faeces and, when these are ingested by a suitable species of intermediate host, the oncosphere contained within the egg is liberated through the influence of intestinal secretions, particularly bile. The activated parasite penetrates the mucosa of the small intestine... 

The mucosa of the small intestine is lined by a simple columnar epithelium, which evaginates into villi and invaginates into crypts, as shown schematically in Fig. 10.11. The lamina propria of the small intestine forms the core of villi... 

Okabe K, Keenan RW, Schmidt G (1968) Phytosphingosine groups as quantitatively significant components of the sphingolipids of the mucosa of the small intestines of some mammalian species. Biochem Biophys Res Com-mun 31 137-143... 

Q1 Celiac patients are sensitive to the gluten in wheat, barley and rye, which damages the mucosa of the small intestine. What are the characteristics of the normal mucosa in the duodenum, jejunum and ileum ... 

The mucosa of the small intestine has an enormous surface area because of the presence of villi. Villi are covered by absorptive columnar epithelial cells whose surface is further increased by microvilli (brush border), on which carbohydrate and peptide digestive enzymes and transport processes involved in absorption are situated. Pits between the villi contain undifferentiated cells which move up the villi, mature, function for a few days and are shed into the lumen of the gut. 

Lipoproteins are macromolecules comprising proteins (= apolipoproteins, apoproteins) and lipids. They transport water-insoluble lipids in the blood, with the exception of the albumin-bound free fatty acids. Only short-chain fatty acids are dissolved in plasma. The lipoproteins are formed in the liver and in the mucosa of the small intestine. (14)... 

Very low density lipoproteins (VLDL) are synthesized in the liver cell at the contact area of the smooth and rough endoplasmic reticulum and, to a very minor degree, in the mucosa of the small intestine. They have a particle size of 30-80 nm and consist of 90% lipids and 8 — 13% proteins. Their density is <1.006 g/ml. The predominant apohpoproteins are B, C III, and E. They are designated as pre-beta lipoproteins on the basis of their electrophoretic migration. The main function of VLDL is the transport of triglycerides of endogenous origin, (s. fig. 3.8)... 

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

Mucous Surface. The mucosa of the small intestine consists of three layers (Fig. 2) an absorptive layer, a continuous single sheet of columnar epithelium the lamina propria, a layer heterogeneous in composition and cell type and the muscularis mucosa, a muscular layer separating the mucosa and submucosa. 

ALP activity is present in most organs of the body and is especially associated with membranes and cell surfaces located in the mucosa of the small intestine and proximal convoluted tubules of the kidney, in bone (osteoblasts), liver, and placenta. Although the precise metabolic function of the enzyme is not yet understood, it appears that ALP is associated with lipid transport in the intestine and with the calcification process in bone. 

Glucose is also an important ingredient as it acts as a carrier for the transport of sodium ions, and hence water, across the mucosa of the small intestine, as well as providing the energy necessary for that process. 

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

The mucosa of the small intestine metabolizes dietary glutamine, glutamate, asparagine, and aspartate by oxidation to CO2 and H2O, or by conversion to lactate, alanine, citrulline, and NH3. These intermediates and the unmetabolized dietary amino acids are transferred to the portal blood and then to the liver for further metabolism. 

Desikan et al. (1975) present the autopsy findings of a young person suffering from intractable leprosy reaction treated for 4 months with clofazimine in a dose of 300 mg daily. A generalized yellow coloration of fatty tissue, brick-red tinting of muscle and viscera, and extreme congestion and edema of the mucosa of the small intestine were found and considered not to be of infectious origin. Deposits of clofazimine crystals were found in the intestinal mucosa. 

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