STOMACH::
It is J-shaped hollow organ lying in the abdomen under the diaphargm its major part is to the left of the midline it distends when it is filled up its capacity is 1-2 litres it stores food and partially digests it biochemically by the gastric juice that it secretes its mechanical digestion is by gastric contractions with cardiac and pyloric sphinctres closed
Stomach has two surfaces (anterior and posterior) two curves (the lesser and the greater curvature) and two orifices (cardiac sphinctre above and the pyloric sphinctre below) Upper part of the stomach above the level of the cardiac sphinctre is called fundus the part below the level of cardiac notch is called body portion below the incisura angularis forms the pylorus the pylorus is subdivided into pyloric antrum and the narrow pyloric canal which follows it
 |
| fig:: Opened up stomach |
Histologically stomach consists of serosa muscularis externa submucosa muscularis interna and mucosa serosa is made up of areolar connective tissue muscularis externa consists of three layers of muscle fibers they are:: (1) Longitudinal (2) Circular and (3) Oblique from outside inwards they are responsible for muscular contractions which churn the food submucosa is of usual nature consisting of areolar connective tissue blood vessels and nerve fibers muscularis interna is the characteristic of stomach and consists of 2-3 layers of muscles running longitudically and circularly
The innermost part of stomach i.e mucosa is relatively thicker and consists of number of folds called rugae Rugae contain a very large number of tubular glands which secrete the gastric juice
Tubular glands are of 3types: (1) Those that secrete pepsin (the peptic glands) (2) Oxyntic glands that secrete hydrochloric acid and (3) Mucus glands that secrete the alkaline mucus there are totally 30 million glands in the stomach the oxyntic glands are concentrated in the fundus of the stomach the body of the stomach is full of peptic glands and the mucus glands are found in the pylorus portion of the stomach
The stomach has a rich blood supply through gastric vessels it is supplied with autonomic nerves both the sympathetic and parasymapthetic The sympathetic nerves inhibit the secretomotor activity of the stomach and the parasympathetic nerve (vagus) stimulates the same
0 Comments