The stomach is a J-shaped organ that receives food from the esophagus. It has four portions: the cardiac portion where the esophagus connects, the fundus which is a domed structure above the esophageal opening, the body which is the largest and central region, and the pyloric region near the small intestine. The stomach contains gastric glands that secrete gastric juices like hydrochloric acid and the enzyme pepsin to break down food into a semi-fluid substance called chyme. Muscular contractions help mechanically break down food, which is then released in small amounts through the pyloric sphincter into the small intestine.

1. Anatomy & physiology of
stomatch
prepared by irfan ullah
Bsn 3rd semester

2. NWCON
•stomatch.
• stomatch is a muscular hollow organ that
takes food from esophagous , mixes and
break down into small parts for absorbation
and passes it down to the small intestine .
• the food in the stomatch is called chyme
• Shape.it has,J,shaped structure
• Structure of stomatch.stomatch has four
portions.

3. Four portions of stomatch
• Cardiac portion. the part where esophagous
connects to the stomatch, through which food enter
to the stomatch .
• sphincter. it have sphincter called cardiac sphincter,
which prevent the back flow of food from
stomatch,located inferior to the diaphraghm.
• Fundus portion
• it is the domed shaped structure of stomatch called
fundus.

4. • it is expanded area curving up above the esophageal
opening.
• Body.it is the central abd largest region of stomatch.
• more volume occuped by it
• Pylorus region.the lower narrow region near to small
intestine us called pylorus region.
• sphincter.in the lower portion there is a sphincter
called pyloric sphincter .
• this sphincter is b/w duodenum and stomatch, that
prevent the food back to stomatch .
• about 14gm chyme passes at a time
• the sphincter is composed of smooth muscles.

5. • the sphincter also called valve which allow the food
to enter into small intestine .
Layers of stomatch.
• stomatch has four layers .
• 1)Mucosa.it is the innermost layer of stomatch wall
,made of connective tissues and posses many tubular
gastric glands .
• simple columnar epithelium made the wall
• there is gastric pits(millions of small holes)
• Submucosa.second layer of stomatch .

6. • made if smooth muscle,helping in churing and
mixing of food with gastric juices
• Serosa. it is the outer most lsyer if stomatch
• made if connective tissue .
• Muscularis . middle layer
• composed of circular and longitudnal circular
obligue muscule . help in contraction and relxation of
stomatch walls.

8. Glands of stomatch
• Gastric glands . those glands which secrete gastric
juices called gastric glands.
• gastric gland together secrete 400-800ml of gastric
juices at each meal
• or 100ml per day.
• Gastric gland cells.several kinds of cells are found
in gastric glands
• 1)parietal cells.
• it secrete Hcl and intrinsic factor.i.e

9. 1)Hcl secretions
• parietal cells membrane bearing proton pump can
secrete H+ actively which is bonded with cl- coming
from food to produceHCL. Hcl is natural acidic .
parietal cellsare stimulated via gastric acid. this acid
concentration in gastric juices is 0.15M
• Fresh Hcl is lower than 01 and later on itadyjusted in
therange of 1-3
• 2)intrinsic factor.parietal cells secrete intrinsic factor
that binds with ingested vitaminB12 and enable it to
be absorbed by the intestine.

10. 2)Chief cells. (zymogen cells)
• they secrete pepsinogen which is in inactive formof
pepsin.
• pesinogen is activated by Hcl to pepsin
• this done when pesinogen us exposed to acidic
medium
• 3)Mucus secreting cells.
• these cells secrete mucus that convert inner
surface of the stomatch and prevent it from
damage by Hcl and pepsin.
• thus mucus form. inner protective covering of
stomatch .

11. • 4)Harmone secreting cells. (endocrine cells)
• there are dufferent type of harmoneor chemicals
secreting cells in stomatch wall.
• some are given below .
• 1)Enterochromaffin cells .
• these cells secrete histamine which helps in
secretions of dastric juices.
(2)G cells.
• these cells secrete harmone gastrin which gastric
juices secretions.
• (3) D cells.these cells secrete somatostatin which
regulates the secretions if gastrin and histamine.

12. phsiology of stomatch
• Absorbation of food and water by the stomatch is
negligible ,but certains vitamins (B12) ions ,drugs,
like asprin and alcohol are absorbed directly.
• Function if stomatch
• (1) storage of food. stomatch is enable us to eat
sufficient amount of food and store for long time
with out further intake of food.beside storage
capacity of stomatch ,we would need food intake
in small amont throughout aday due to slow
intestinal digestion.

13. (2)Digestion
• two type digestion 9ccured in stomatch.
• (1)chemical digestion . stomatch produces gastric
juices which start the chemical digestion of
protein. for example pepsin digest the larger
proteins unto smaller proteins called peptides.
• (2)physical digestion. stomatch has powerfull
muscules. which mechanically digest foid into small
absorable pieces.

14. (3) Help in immunity
• in addition to breaking down of food gastric juices
also kill bacteria in the food mucus also form a
protective coat ob stomatch limning , to protect it
from Hcl pepsin and other pathigens.
• (4)Chyme formation. As a result of chemical. and
mechanical digestion, food is converted into semi
fluid soupy form called chyme.
• (5)Absorbation of food.
• the absorbtion if food and water us negligble but
certain ions and drug are actively absorbed

15. (6)Transfer of food
• small quantities of chyme about 14grams at a time
passed through the pyloric opening to duodenum .

16. Mechanism of secretions of
Gastric Juices
• sight , smell, taste, hearing of delicious food
stimulate the nervious system which send
messages to gastric glands to secrete small amount
of gastric juices .
• chemical control.
• when more protenious food reaches the stomatch
,where already present gastric juices start
digestion of protein.
• protein are converted in smaller peptides.

17. • stimulate the endocrine cells to secrete harmone
gastrin.
• the Gastrin circulate in blood , which carried back
to stomatch and stimulate gastric gland to secrte
large amount of gastric juices
• thus more protein in food more gastrin secrete for
dugestion.
• (2) the contact of the proteneous food with lining
if the stomatch also causes the stimulation of
endocrine cell of stomatch to secrete gastrin .

18. •The
End