Structure of Human Stomach by Prabeen

Structure of Human Stomach by Prabeen
Anatomy of human stomach

1. STRUCTURE OF HUMAN STOMACH Prabeen Kumar Mahato 4 th semester J. K. College, Purulia

2. Introduction to Stomach The stomach is a muscular bag forming the most dilated and most distensible part of the gastrointestinal tract and has a J-like shape . It acts as a reservoir of food and helps in digestion of proteins and very insignificantly of fats and carbohydrates.

3. Location of Stomach The stomach lies obliquely in the upper and left part of the abdomen , occupying the epigastric , umbilical and left hypochondriac regions. Adult stomach varies from 15 to 25 cm long, but its diameter and volume depend on how much food it contains. 1 2 3 4 5 6 9 8 7

4. GROSS ANATOMY OF STOMACH

5. Parts of Stomach The stomach has two orifices or openings , two curvatures or borders , two notches, two surfaces and two parts . Fig. Structure of Human Stomach

6. Two Orifices of Stomach Cardiac orifice: Oesophagus opens into stomach by this orifice. Its opening is regulated by lower oesophageal sphincter or cardiac sphincter . Pyloric orifice: Stomach opens into duodenum by this orifice. Its opening is regulated by pyloric sphincter .

7. Two Curvatures of Stomach Greater curvature: It is the convex surface of the stomach which provides attachment for the gastrosplenic ligament , gastrophrenic ligament and the greater omentum . Lesser curvature: It is the concave surface of the stomach which provides attachment for the lesser omentum .

8. Two Surfaces of Stomach The anterior or anterosuperior surface faces forwards and upwards. The posterior or posteroinferior surface faces backwards and downwards.

9. Two Parts of Stomach Cardiac part: By a line drawn downwards and to the left from the cardiac end to the angular notch (lowest point of lesser curvature). The line is extended further to the greater curvature. It is further subdivided into two parts – Fundus: The fundus of the stomach is the upper convex dome shaped part situated above the horizontal line drawn at the level of the cardiac orifice. Body: The body of the stomach lies between the fundus and the pyloric antrum.

10. Two Parts of Stomach Pyloric Part: It is the distal part of the stomach and further subdivided into two parts. Pyloric Antrum: The pyloric antrum is separated from the pyloric canal by an inconstant sulcus, sulcus intermedius present on the greater curvature. Pyloric Canal: It is narrow and tubular part of the pyloric part and terminates at pylorus .

11. Two Notches of Stomach Human stomach has two notches : Cardiac notch: It is the superior angle created when the oesophagus enters the stomach. Angular incisure: It is a bend on the lesser curvature near the pyloric antrum. Its other names are angular notch or incisura angularis .

12. MICROSCOPIC ANATOMY OF STOMACH

13. MICROSCOPIC ANATOMY OF STOMACH The muscularis and mucosa layers of stomach are modified to perform special functions. Gastric Rugae/Folds: When the stomach is empty, the mucosa lies in large folds, or rugae, that can be seen with the unaided eye. Fig. Gastric rugae

14. MICROSCOPIC ANATOMY OF STOMACH Gastric Pit: Sometimes several gastric glands opens on a common chamber called gastric pit which opens in turn on the surface of the mucosa. Fig. Gastric pit

15. Layers of Stomach Wall Fig. Stomach wall, sectional view

16. LAYERS OF STOMACH WALL The mucosa consists of an epithelial lining , an underlying lamina propria and a thin layer of smooth muscle . The submucosa contains denser connective tissue with larger blood and lymph vessels and the submucosal (Meissner) nerve plexus . The thick muscularis (or muscularis externa ) is composed of smooth muscle cells organized as two or three sublayers. The serosa is a thin layer of loose connective tissue.

17. Stomach Fig. Structure of Human Stomach

18. Summary Stomach is a very important part of digestive system. Its is the widest part of the alimentary canal starts with the cardia then fundus and body then ends with pylorus to duodenum. It has many glands and gastric pits for secretions of HCl, Castle’s intrinsic factors from oxyntic cells, pepsinogen from chief cells and some hormones. In stomach mainly protein foods get digested by an endopeptidase enzyme pepsin and rennin in case of childs .

19. Bibliography Gray’s Anatomy for Students , 2 nd edition, Churchil Livingstone Elsevier Atlas of Human Anatomy , F. H. Netter, 7 th edition, Elsevier BD Chaurasia’s Human Anatomy , 8 th edition, CBS Human Anatomy & Physiology , E. N. Marieb , 11 th edition, Pearson Principles of ANATOMY & PHYSIOLOGY , Tortora & Derrickson, 15 th edition

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