The stomach___ by sdfwerte

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									       The stomach!!!


By Hannah Bayfield and Esme Gray!
             Year 12
   King Edward VII High School!
                          Introduction
What is the stomach???

The stomach is an enlarged and
muscular saclike organ of the
alimentary canal. It is the principal
organ of digestion.
It is situated between the oesophagus
and the intestines and nearly every
animal has a stomach.
It changes size and shape according to
it’s position in the body and the
amount of food inside it.
  Structure of the stomach!
•The stomach is composed of five layers which starts from the
inside and works its way out.
•The inner most layer is called the mucosa. This is where the
stomach acid and digestive juices are made.
•The next layer is called the submucosa which is surrounded by
the muscularis (a layer of muscle that moves and mixes the
stomach contents).
•The next two layers are the subserosa and the serosa and are
the wrapping for the stomach.




                                                    A cross section of
                                                    the stomach.
         Quick questions!

The stomach is the ………………….. Organ of
digestion???

 Principal

How many layers does the
stomach have???

  Five
The stomach wall
    The wall of the stomach is
    structurally similar to other parts of
    the digestive tube, with the
    exception that the stomach has an
    extra oblique layer of smooth
    muscle, which aids in performance
    of complex grinding motions.
        What protects the stomach?




The stomach is lined with epithelial cells
(goblet cells), which produce and secrete a
bicarbonate-rich solution that coats the
mucosa.
Bicarbonate is an alkaline and neutralizes the
acid secreted by the parietal cells, producing
water in the process.
This is the main way that your stomach
protects itself from auto digestion (the
stomach digesting itself) and the overall acidic
environment.                                       Goblet cell
          Quick questions???

What does the smooth          Aids performance of
oblique extra layer of the    complex grinding
stomach help it to do???
                              motions.


What do the epithelial          A bicarbonate-
cells that line the stomach
produce???                      rich solution
                    Cells in the stomach

There are four major types of secretory epithelial cells that
cover the surface of the stomach. They are:

Mucous cells: These secrete an alkaline mucus that protects
the epithelium against shear stress and acid.

Parietal cells: These secrete hydrochloric acid.

Chief cells: These secrete pepsin, a proteolytic enzyme.

G cells: These secrete the hormone gastrin .                    A parietal cell.
      Can you name the organelles in this
                    cell?
                                    Rough
                                    endoplasmic
Mitochondria                        reticulum.




    Nucleus
                                       Golgi body
 Thank you for
 watching our
presentation!!!

								
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