Stomach

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About Stomach

Inside the human body, there is a sac-like muscular structure called the stomach. It is situated towards the upper-left side of the abdomen just below the liver. The major function of the stomach is to hold and breakdown food and liquid that we consume in our meals. 

The stomach mainly secretes enzymes and acids like hydrochloric acid and enzymes that help in the breakdown of food and other foreign particles like bacterial pathogens. Sometimes secretion of more acid leads to ulcer inside the stomach. Maintaining an acidic medium in the stomach is necessary to kill the unwanted bacteria present in the stomach.  

The stomach structure allows the stomach to undergo muscle contraction at regular intervals to churn the food and enhance the digestion process. The stomach takes approx 40 minutes to a few hours for breaking down food. 

Digestion of Food Inside the Stomach

About 1 litre of food can be held by the stomach comfortably, but we can expand the holding capacity of the stomach up to 4 litres as the stomach has elastic muscles. Because of this elastic nature of the stomach, it can expand when it is full and becomes normal when the food gets digested. The signal is provided by the brain when our stomach gets full, this signal is not immediately provided by the brain. Because of this reason, we should take our food slowly. 

By properly chewing or food, we make the digestion process smoother. One of the major functions of the stomach is to churn the food properly coming from the esophagus so that the small intestine can absorb the molecules easily. When there is proper mixing of food and water in the stomach then they form chyme, after the formation of chyme food is ready to move into the small intestine. Organs like liver, gallbladder and pancreas are also considered as part of the alimentary system, so they also play a crucial role in the digestion process. 

Structure of Stomach

We all know the stomach is a part of the digestive system and is connected to the following organs:

A. Esophagus: It is considered a tube-like organ that acts as a connection between the mouth and throat to the stomach. The gastrointestinal junction is the area where the oesophagus joins the stomach. 

B. Small Intestine (small bowel): It is a long tube-like structure that extends from the stomach to the colon of the large intestine. Posterior part of the small intestine is known as the duodenum, and it is this part that is connected to the stomach.

Different Regions of Stomach

The human stomach is divided into five regions they are:

A. The very first part of the stomach is the cardiac region, which lies just below the oesophagus. It has a cardiac sphincter, which mainly helps to prevent stomach contents from going back up into the oesophagus.

B. Second part is the fundus region and it is the rounded area that lies to the left of the cardia and below the diaphragm. And this is the region where mixing of food and breaking down of food takes place. 

C. Antrum is considered as the lower part of the stomach and the main function of this region is that it holds the broken-down food until it is ready to be released into the small intestine.

D. The pylorus is the part of the stomach that connects to the small intestine. This region includes the pyloric sphincter, which is a thick ring of muscle that acts as a valve to control the emptying of stomach contents (chyme) into the duodenum (first part of the small intestine).

E.  The pyloric sphincter is the last region of the stomach and it also prevents the contents of the duodenum from going back into the stomach.

FAQ (Frequently Asked Questions)

1. Write three main Functions of the Stomach?

Ans. Three main functions of the stomach are listed below:

A. It's one of the major functions is temporary storage for food, which passes from the oesophagus to the stomach where it is held for 2 hours or longer.

B. It also plays a crucial role in mixing and breakdown of food by contraction and relaxation of the muscle layers in the stomach.

3. It performs digestion of food

2. Explain different Layers of the Stomach?

Ans. Different layers of the stomach are discussed below?

1. Very first layer of the stomach is the mucosa (mucous membrane) is the inner lining of the stomach. Appearance of the mucosa is rigid when the stomach is empty, and due to this rigidity, the stomach gets flattened. 

B. Second layer of the stomach is the submucosa. It is made up of connective tissue that contains larger blood and lymph vessels, nerve cells and fibres.

C.  Muscularis Propria (or Muscularis Externa) is the third layer of the stomach that covers the submucosa. It is known to be the main muscle of the stomach and is composed of 3 layers of muscle.

D. The serosa is the fourth layer of the stomach and is made up of a fibrous membrane that covers the outside of the stomach. This layer is also known as the visceral peritoneum.