Question

Match column I with column II and choose the correct option.

Column I	Column II
A.Goblet cells	1.Antibacterial agent
B.Lysozyme	2.mucus
C.Saliva	3.HCl
D.Oxyntic cells	4.Sublingual gland

(a) A - 3, B - 1, C - 4, D - 2
(b) A - 1, B - 3, C - 4, D - 2
(c) A - 2, B - 3, C - 1, D - 4
(d) A - 4, B - 1, C - 2, D - 3
(e) A - 2, B - 1, C - 4, D - 3

Answer 1

All the cells in column I play an important role in the smooth and proper functioning of the digestive system. The digestion begins in the mouth with the help of some alkaline secretions. Their functioning stops in the interior of the stomach.

Complete answer:
Saliva is a mixture of water, electrolytes, salivary amylase, and lysozyme. Saliva is a fluid synthesized and secreted by salivary glands located in the buccal cavity. The sublingual gland is one of the three types of salivary glands. Lysozyme is an enzyme that is present in extracellular secretion like saliva and tears. It kills any bacteria that may have entered via the food in our oral cavity. Parietal cells or oxyntic cells are a type of gastric glands that are located in the mucous layer of the stomach. They secrete HCl that not only provides an acidic medium for various metabolic reactions in the stomach but also kills any pathogens that may have entered the alimentary canal via the intake of food. Goblet cells are located in the epithelial layer of the stomach. It releases alkaline mucus to protect the stomach wall from the corrosive action of HCl.

Additional Information:
- Sublingual glands are situated beneath the tongue and open via the duct of the Rivinus into the oral cavity.
- Two other salivary glands are present which are parotid glands and submandibular glands.
- Salivary amylase or ptyalin is an enzyme that converts starch into maltose, isomaltose, and $\alpha$- dextrins.
- Salivary amylase works best at a pH of 6.8 and thus it no longer remains functional once it enters the stomach acidic environment.
- The secretions of the gastric glands are collectively referred to as gastric juice. They are located in the mucosa layer of the stomach. These include chief cells, oxyntic cells, and goblet cells.
So, the correct answer is ‘(e) A - 2, B - 1, C - 4, D - 3.’

Note:
- Chief cells or zymogen cells secrete pepsinogen in its inactive form that upon conversion to pepsin initiates the digestion of proteins.
- Pepsin is a proteolytic enzyme, converting proteins into its shorter segments i.e tripeptides and dipeptides. It requires an acid-rich environment for its action.