March 10 Lecture - March 10, 2009 The Digestive System The...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
March 10, 2009 The Digestive System The Stomach - Functions o Consistently process food (accommodates substantial amount of food) About 1 litre of food will be intaken before an individual can experience discomfort o Production of gastric juices o Ensures proper mixture of gastric juices through the stomach content o Movment of food into the small intestine Gastric Juices - Produced by the mucosal lining of the stomach - Gastric glands or gastric pits are located in between rugae of the stomach - There are various types of cells that make up the mucosa o Parietal cells: distributed throughout the body (the midregion of the gastric wall) Responsible for the synthesis of substantial amounts of HCl Every 24 hours these cells will have produced approximately 2 L of the acid HCl is not nescessarily essential for the digestion of food – the small intestine will take on most of the role HCl brings about the denaturation of proteins (altering the configuration of the protein – NOT digesting it) Allows enzymes to more effectively act on the target molecules HCl also activates some of the enzymes which are secreted by the stomach Ex. Pepsinogen which in the presence of HCl will become activated into pepsin HCl also tends to control bacterial composition in the stomach (kills off most of the bacteria) o Chief cells: These are located at the base of the gastric pits and distributed throughout the midregion (the body and antrum) This is the location where pepsinogen is produced and is being released into the stomach HCl will convert this enzyme to pepsin and this enzyme will assist in the breakdown of proteins Pepsin, the active form of the enzyme secreted by the chief cells, is only active in an acidic environment Once the contents of the stomach are passed into the small intestine, the contents are neutralized by secretions from the pancreas, which causes the enzyme to become inactive o Mucous cells: Very abundant, found at the neck of the gastric pits (closest to the lumen of the stomach) throughout the body and the antrum. These cells make up most of the gastric mucosa at the based of the fundus region as well These cells are responsible for the production of mucous Increased production of mucous can be caused by
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
In normal conditions a thin layer of mucous covers the mucosal layer of the stomach (1-2 mm in thickness) Provides protection to the mucosal lining of the stomach from mechanical or physical irritation (acts as a lubricant) Mucous is alkaline, which neutralizes the surface of the mucosa and is one
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/23/2011 for the course BIOL 2125 taught by Professor Dr.park during the Winter '02 term at A.T. Still University.

Page1 / 5

March 10 Lecture - March 10, 2009 The Digestive System The...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online