Stomach is J-shaped, hollow organ that digests food.
Stomach is connected above lower end of oesophagus and below to the duodenum.
Stomach is directly located inferior to the diaphragm and left part of the abdominal cavity, protected by rib cage.
Stomach lies obliquely in upper and left part of the abdomen, situated in epigastric, umbilical and left hypochondriac region.
Size and Shape of Stomach
Length of stomach - 25 cm long
Capacity of stomach in Adult; 1.5 - 2 litres
Capacity of stomach at Puberty; about 100 ml
Capacity of stomach at Birth; about 30ml
Sttructure of Stomach
Stomach has two orifices (opening) and two curvature -
Two orifice are -
1. Cardiac orifice
2. Pyloric orifice
Two curvature are -
1. Lessee curvature
2. Greater curvature
Orifice of Stomach
1. Cardiac Orifice
Orifice of Stomach
1. Cardiac Orifice
Stomach continue with esophagus at gastroesophageal (lower esophageal) or cardiac orifice, lies level of T11 vertebrae.
Cardiac orifice is opening by which esophagus communicates with stomach.
Bolus enters stomach through cardia opening. It is called cardiac orifice because located near heart.
2. Pyloric Orifice
Stomach continuous with duodenum at pyloric orifice. It is opening between stomach and upper part of duodenum.
Partially digested nutrients leave stomach and enters small intestine through pyloric orifice. Pylori orifice permit fluids but not solids to pass into the duodenum.
Cardiac orifice (Lower esophageal) and pyloric orifices both contain sphincter.
Pyloric Sphincter is more powerful then lower esophageal sphincter with band of circular smooth muscle that control the movement of partially digested food, liquids from pylorus into duodenum.
Curvature of Stomach
Curvatures of the stomach are -
1. Greater curvature
2. Lesser curvature
Greater Curvature
Stomach has greater curvature towards the left side of body.
It is convex curvature, from left or lateral border of stomach.
It provides attachment to greater monument ( sheet of fatty tissue stretch over the abdomen).
At upper end, greater curvature present cardiac notch (separated from esophagus or separated from fundus of stomach).
Lesser Curvature
Lesser curvature forms right or posterior border of the stomach.
It is concave curvature and forms right or medial or posterior border of stomach.
It provide attachment of lesser omentum.
Parts of Stomach
Parts of Stomach
Stomach have sections-
1. Small cardiac region
Region of stomach near cardiac orifice.
2. Fundus
Upper concave dome-shaped, above level of cardiac orifice.
3. Body
Body of stomach largest central portion lie between fundus and pyloric antrum.
4. Pyloric region
Region connect duodenum (narrow part).
A. Pylori antrum
Region connects to body of stomach.
B. Pylori canal
(narrow portion to the pyloric orifice and duodenum)
Pylori canal is tubular-shape and 2.5cm long.
Wall of the stomach
Layers of stomach walls-
1. Serosa
2. Muscularis externa
3. Submucosa
4. Mucus membrane or mucosa
Function of Stomach
The function of stomach are -
1. Mechanic function; breakdown of ingested food.
2. Temporary storage for food (held for 2 hours) then release into small intestine.
3. Digestive action
4. Chemical digestion; secrete HCL and enzyme (initiate digestion of protein). Gastric juice mainly act on protein.
5. Partially digestion of food
6. Churns ingested nutrient
7. Gastric motility
8. Break down nutrients in small particle, mixes with gastric juice form chyme.
9. Regulation of passage of gastric content into the duodenum.
10. Production and secretion of intrinsic factor; glycoprotein required for absorption of vitamin B12 in small intestine.
11. Glycoprotein enable body to absorb vitamin B12.
12. Kill bacteria that enter stomach in food.
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