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Argentaffin
Argentaffin refers to cells which take up silver stain. Enteroendocrine cells are sometimes also called "argentaffins", because they take up this stain. An argentaffin cell is any enteroendocrine cell, a hormone-secreting cell present throughout the digestive tract. It is a property of melanin, and special stain can be applied to identify those granules. Fontana-Masson stain uses the fact that those cells can reduce the silver salts to metallic silver (brownish-black) color without the aid of reducing agent, which is the definition of Argentaffin cells. Argentaffin cells , one of the round or partly flattened cells occurring in the lining tissue of the digestive tract and containing granules thought to be of secretory function. These epithelial cells, though common throughout the digestive tract, are most concentrated in the small intestine and appendix. The cells located randomly within the mucous membrane lining of the intestine and in tubelike depressions in that lining known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Stain
In pathology, silver staining is the use of silver to selectively alter the appearance of a target in microscopy of histological sections; in temperature gradient gel electrophoresis; and in polyacrylamide gels. In traditional stained glass, silver stain is a technique to produce yellow to orange or brown shades (or green on a blue glass base), by adding a mixture containing silver compounds (notably silver nitrate), and firing lightly. It was introduced soon after 1800, and is the "stain" in the term "stained glass". Silver compounds are mixed with binding substances, applied to the surface of glass, and then fired in a furnace or kiln. History Camillo Golgi perfected silver staining for the study of the nervous system. Although the exact chemical mechanism by which this occurs is unknown, Golgi's method stains a limited number of cells at random in their entirety. Silver staining was introduced by Kerenyi and Gallyas as a sensitive procedure to detect trace amounts of prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enteroendocrine Cells
Enteroendocrine cells are specialized cells of the gastrointestinal tract and pancreas with endocrine function. They produce gastrointestinal hormones or peptides in response to various stimuli and release them into the bloodstream for systemic effect, diffuse them as local messengers, or transmit them to the enteric nervous system to activate nervous responses. Enteroendocrine cells of the intestine are the most numerous endocrine cells of the body. They constitute an enteric endocrine system as a subset of the endocrine system just as the enteric nervous system is a subset of the nervous system. In a sense they are known to act as chemoreceptors, initiating digestive actions and detecting harmful substances and initiating protective responses. Enteroendocrine cells are located in the stomach, in the intestine and in the pancreas. Microbiota plays key roles in the intestinal immune and metabolic responses in these enteroendocrine cells via their fermentation product ( short chain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanin
Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the amino acid tyrosine is followed by polymerization. The melanin pigments are produced in a specialized group of cells known as melanocytes. Functionally, eumelanin serves as protection against UV radiation. There are five basic types of melanin: eumelanin, pheomelanin, neuromelanin, allomelanin and pyomelanin. The most common type is eumelanin, of which there are two types— brown eumelanin and black eumelanin. Pheomelanin, which is produced when melanocytes are malfunctioning due to derivation of the gene to its recessive format is a cysteine-derivative that contains poly benzothiazine portions that are largely responsible for the of red yellow tint given to some skin or hair colors. Neuromelanin is found in the brain. Research has been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vasoconstriction. Approximately 90% of the serotonin that the body produces is in the intestinal tract. Biochemically, the indoleamine molecule derives from the amino acid tryptophan, via the (rate-limiting) Tryptophan hydroxylase, hydroxylation of the 5 position on the ring (forming the intermediate 5-Hydroxytryptophan, 5-hydroxytryptophan), and then Aromatic L-amino acid decarboxylase, decarboxylation to produce serotonin. Serotonin is primarily found in the enteric nervous system located in the human gastrointestinal tract, gastrointestinal tract (GI tract). However, it is also produced in the central nervous system (CNS), specifically in the raphe nuclei located in the brainstem, Merkel cells located in the skin, Neuroendocrine cell#Pulmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peristalsis
Peristalsis ( , ) is a radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which is preceded by a simultaneous contraction of the longitudinal muscle and relaxation of the circular muscle in the lining of the gut. In much of a digestive tract such as the human gastrointestinal tract, smooth muscle tissue contracts in sequence to produce a peristaltic wave, which propels a ball of food (called a bolus before being transformed into chyme in the stomach) along the tract. The peristaltic movement comprises relaxation of circular smooth muscles, then their contraction behind the chewed material to keep it from moving backward, then longitudinal contraction to push it forward. Earthworms use a similar mechanism to drive their locomotion, and some modern machinery imitate this design. The word comes from New Latin and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
