Cambios

'''Peristáltico'''

'''Peristáltico'''

Contracción antagonisticas de los músculos longitudinales ''y'' circulares. Transporte quimo por el intestino delgado, pero las contracciones pueden ser débil para que haya tiempo para la absorción. Cuando un ''onda'' peristáltica de contracción alcanza el final del [[Ileon - Anatomía & Fisiología|íleon]], otro comienza en el [[Duodeno - Anatomía & Fisiología|duodeno]]. Esto se conoce como un complejo ''mioeléctrica migrando''.

Contracción antagonisticas de los músculos longitudinales ''y'' circulares. Transporte quimo por el intestino delgado, pero las contracciones pueden ser débil para que haya tiempo para la absorción. Cuando un ''onda'' peristáltica de contracción alcanza el final del [[Íleon - Anatomía & Fisiología|íleon]], otro comienza en el [[Duodeno - Anatomía & Fisiología|duodeno]]. Esto se conoce como un complejo ''mioeléctrica migrando''.

===Para segregar enzimas para la digestión del quimo y absorción de productos de la digestión===

===Para segregar enzimas para la digestión del quimo y absorción de productos de la digestión===

====Digestión y Absorción de Carbohidratos====   

====Digestión y Absorción de Carbohidratos====   

The main soluble carbohdrates found in food are starch, found mainly in plants, and glycogen, found mainly in animal meat. There are two types of starch, ''amylose'' which has α1-4 glycosidic links and, ''amylopectin'' which has α1-4 glycosidic links and α1-6 glycosidic links making it branched (branches every glucose 25 residues). ''Glycogen'' is synthesised in the [[Hígado - Anatomía & Fisiología|hígado]] and [[Muscles - Anatomía & Fisiología|muscle]] and is similar to amylopectin as it has both α1-4 glycosidic links and α1-6 glycosidic links. However, it is more highly branched with shorter branches (branches every 12-18 glucose residues).

The main soluble carbohdrates found in food are starch, found mainly in plants, and glycogen, found mainly in animal meat. There are two types of starch, ''amylose'' which has α1-4 glycosidic links and, ''amylopectin'' which has α1-4 glycosidic links and α1-6 glycosidic links making it branched (branches every glucose 25 residues). ''Glycogen'' is synthesised in the [[Hígado - Anatomía & Fisiología|hígado]] and [[Músculos - Anatomía & Fisiología|músculo]] and is similar to amylopectin as it has both α1-4 glycosidic links and α1-6 glycosidic links. However, it is more highly branched with shorter branches (branches every 12-18 glucose residues).

The '''first stage''' of carbohydrate digestion begins with α-amylase, which is an endoglycosidase. ''(This means it breaks bonds in the middle of the polymer to produce di-, tri- and oligo-saccharides).'' α-Amylase is present in [[:Categoría:Glándulas Salivales - Anatomía & Fisiología|saliva]]. Salivary α-amylase is inactivated when it enters the [[Estómago Monogástrico - Anatomía & Fisiología|stomach]] due to it's acidic pH.

The '''first stage''' of carbohydrate digestion begins with α-amylase, which is an endoglycosidase. ''(This means it breaks bonds in the middle of the polymer to produce di-, tri- and oligo-saccharides).'' α-Amylase is present in [[:Categoría:Glándulas Salivares - Anatomía & Fisiología|saliva]]. Salivary α-amylase is inactivated when it enters the [[Estómago Monogástrico - Anatomía & Fisiología|stomach]] due to it's acidic pH.

Carbohydrate digestion continues in the lumen of the [[Intestino Delgado - Resumen - Anatomy & Physiology|intestino delgado]] as pancreatic α-amylase enters the [[Duodeno - Anatomía & Fisiología|duodeno]] in the pancreatic duct. This is the site of the majority of carbohydrate digestion. The '''second stage''' is the digestion of di-, tri-, and oligo-saccharides to monosaccharides. This is done by di-, tri-, and oligo-saccharidases which have a glycocalyx to trap their substrate. They are bound to enterocytes. The main dissacharides that are broken down are; Maltose into two glucose molecules, sucrose into a glucose and fructose molecule and lactose into a glucose and galactose molecule. These monomers can then be absorbed.

Carbohydrate digestion continues in the lumen of the [[Intestino Delgado - Resumen - Anatomía & Fisiología|intestino delgado]] as pancreatic α-amylase enters the [[Duodeno - Anatomía & Fisiología|duodeno]] in the pancreatic duct. This is the site of the majority of carbohydrate digestion. The '''second stage''' is the digestion of di-, tri-, and oligo-saccharides to monosaccharides. This is done by di-, tri-, and oligo-saccharidases which have a glycocalyx to trap their substrate. They are bound to enterocytes. The main dissacharides that are broken down are; Maltose into two glucose molecules, sucrose into a glucose and fructose molecule and lactose into a glucose and galactose molecule. These monomers can then be absorbed.

Absorption of glucose and galactose is coupled to sodium absorption and occurs through a symport called SGLT-1. Sodium potassium pumps in the enterocyte plasma membrane pump sodium out of the cell so that there is a higher concentration in the intestinal lumen than in the enterocyte. There is a net negative charge on the cell. Sodium diffuses down it's concentration and electrochemical gradient back into the enterocyte through the symport. This releases some energy. The energy release is used to transport glucose and galactose up their concentration gradients into the enterocyte. Glucose and galactose can then diffuse into the blood (portal vein) by carrier mediated diffusion via a GLUT-5 transporter.

Absorption of glucose and galactose is coupled to sodium absorption and occurs through a symport called SGLT-1. Sodium potassium pumps in the enterocyte plasma membrane pump sodium out of the cell so that there is a higher concentration in the intestinal lumen than in the enterocyte. There is a net negative charge on the cell. Sodium diffuses down it's concentration and electrochemical gradient back into the enterocyte through the symport. This releases some energy. The energy release is used to transport glucose and galactose up their concentration gradients into the enterocyte. Glucose and galactose can then diffuse into the blood (portal vein) by carrier mediated diffusion via a GLUT-5 transporter.

====Digestión y Absorción de Triacilgliceroles====

====Digestión y Absorción de Triacilgliceroles====

Triacylglycerols (TAGs) are digested by lipases. TAG digestion begins in the [[Cavidad Oral - Resumen - Anatomía & Fisiología|cavidad oral]], where lingual lipase is secreted in the [[:Categoría:Glándulas Salivales - Anatomía & Fisiología|saliva]]. It removes a fatty acid from the 3 position on the glycerol molecule producing 1,2-diacylglycerol(1,2 DAG) and a free fatty acid. TAG digestion continues in the small intestine, with pancreatic lipase and bile from the [[Hígado - Anatomía & Fisiología|hígado]]. Pancreatic lipase is water soluble and the TAG and 1,2-DAG are lipid soluble. Bile creates an interface for the enzyme to digest the lipid molecules. Bile also emulsifies fats; it reduces the size of lipid droplets increasing the surface area available for digestion. Pancreatic lipase removes any further fatty acids from the 3 position and then from the 1 position to produce 2-monoacylglycerol (2-MAG) and a fatty acid. Pancreatic lipase is unable to remove the fatty acid from the 2 position, so an enzyme called '''isomerase''' transfers the fatty acid from the 2 postion to the 1 postion to produce 1-monoacylglycerol (1-MAG). Pancreatic lipase can then remove the fatty acid from the 1 position to produce a fatty acid and glycerol.

Triacylglycerols (TAGs) are digested by lipases. TAG digestion begins in the [[Cavidad Oral - Resumen - Anatomía & Fisiología|cavidad oral]], where lingual lipase is secreted in the [[:Categoría:Glándulas Salivares - Anatomía & Fisiología|saliva]]. It removes a fatty acid from the 3 position on the glycerol molecule producing 1,2-diacylglycerol(1,2 DAG) and a free fatty acid. TAG digestion continues in the small intestine, with pancreatic lipase and bile from the [[Hígado - Anatomía & Fisiología|hígado]]. Pancreatic lipase is water soluble and the TAG and 1,2-DAG are lipid soluble. Bile creates an interface for the enzyme to digest the lipid molecules. Bile also emulsifies fats; it reduces the size of lipid droplets increasing the surface area available for digestion. Pancreatic lipase removes any further fatty acids from the 3 position and then from the 1 position to produce 2-monoacylglycerol (2-MAG) and a fatty acid. Pancreatic lipase is unable to remove the fatty acid from the 2 position, so an enzyme called '''isomerase''' transfers the fatty acid from the 2 postion to the 1 postion to produce 1-monoacylglycerol (1-MAG). Pancreatic lipase can then remove the fatty acid from the 1 position to produce a fatty acid and glycerol.

''NB: Pancreatic lipase works quickly, whilst isomerase works slowly. Thus, 2-MAG often accumulates and is absorbed (70% of digested TAG are absorbed as 2-MAG). A small proportion is absorbed as 1-MAG (6%).''

''NB: Pancreatic lipase works quickly, whilst isomerase works slowly. Thus, 2-MAG often accumulates and is absorbed (70% of digested TAG are absorbed as 2-MAG). A small proportion is absorbed as 1-MAG (6%).''

==Enlaces==

==Enlaces==

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