Tag: coordination in life processes

According to the body's needs, the stomach decides what to do with the food. If the small intestine is full and busy absorbing molecules from a previous meal, for instance, the stomach temporarily stores the food. On the other hand, if the body is in need of nutrients and the small intestine is ready for absorption, the stomach begins to break down the macromolecules found in the food and creates a semi-liquid mixture called chyme. This decision-making step of the stomach helps control the pace of the digestive system. The stomach of vertebrates is able to break down macromolecules due to its highly acidic environment, which causes molecular bond stress and forces them to break. So, the original function of the vertebrate stomach was storage but, due to acidic medium it also breaks down the food. Thus, option A is correct.

During digestion process fist food is ingested by mouth where chewing churning and mixing of food take place and make semi solid paste of food called as a bolus. Bolus then enters into the oesophagus where food moves through peristaltic movement and enters into the stomach. Thus, the correct answer is option C.

The stomach wall secretes gastric juices and a mixture of HCl, pepsinogen and mucous. HCl increases the pH of the stomach due to which pepsinogen gets activated and gets converted into the active form pepsin which digests the protein molecule. Thus, the correct answer is option D. 

The stomach is a J-shaped, hollow organ located just inferior to the diaphragm in the left part of the abdominal cavity. It is located between the oesophagus and connects with the duodenum. It has two parts fundus and pyloric. 

The gastric glands of stomach produce gastric juice, which contains pepsinogen, HCl, and mucus. HCl imparts highly acidic pH to stomach which in turn supports conversion of inactive pepsinogen into active pepsin. The proper acidic environment of stomach triggers the opening of one way pyrrolic sphincter which in turn allow the chyme to move into the small intestine for further digestive processes. Thus, the correct answer is option C.

Parietal cells in the mucosa are found in the inner lining of the stomach which secrete hydrochloric acid (HCl) into the stomach lumen, or cavity. It decreases the pH of the stomach and has corrosive nature hence can harm the stomach wall. The gastric juice consists mucous also. It gets deposits on the inner wall of the stomach to protect it from the corrosiveness of HCl.