Question

The lining of the stomach is protected by
A. Hydrochloric acid
B. Mucous
C. Digestive juices
D. None of the above

Answer 1

Hint: Stomach generally stores the food and digests it by means of enzymes and gastric acids. The lining of the stomach generally secretes the enzyme and gastric acids.

Step by step answer:Stomach is one of the organs in the digestive system. The other organs of the digestive system include the mouth, buccal cavity, pharynx, esophagus, small intestine, large intestine, and anus. The stomach is a sac-like, J-shaped, and muscular organ. The stomach can be divided into four parts namely the cardiac, the fundus, the body, and the pylorus. Cardia is the part in which the esophagus opens and empties its contents into the stomach. In this region, there is a presence of sphincter which is called “cardiac sphincter” or “anterior sphincter”. This sphincter prevents the action of bringing swallowed food up again to the mouth. The fundus is an upper curved part of the stomach. The body is the main and central region of the stomach. The pylorus is the remaining portion of the stomach which opens into the small intestine i.e., duodenum. In this stomach, there is a presence of sphincter which is called “pyloric sphincter” or “posterior sphincter”. This sphincter regulates the passage of food into the duodenum.
The stomach lining comprises the mucosa, submucosa, muscularis externa, subserosa, and serosa. These layers are responsible for churning of food i.e. it physically breaks down the food and they produce gastric juices. The digestive juices or gastric juices composed of hydrochloric acid and pepsin which is a digestive enzyme. The stomach has a number of gastric glands and the function of these glands can change depending on their location. These glands produce gastric juices as well as mucous. Gastric juices help in digestion while mucous protects the stomach lining.
Hence, the correct answer is option B, i.e. The lining of the stomach is protected by mucous.

Note: Generally, the churning process breaks the food into small molecules and also facilitates the mixing of foods with gastric juices. The pH of the stomach is very low so it can damage the cell lining of the stomach so mucous is secreted in order to protect the lining.