The salivary gland secretes saliva which contains the enzyme.

Appeared in: RRB Staff Nurse Jaipur-6th June 2018

Explanation

The salivary glands secrete saliva, which contains the enzyme ptyalin.
Ptyalin is also known as salivary amylase.
Its primary function is to initiate the digestion of starches (carbohydrates) in the mouth.
Ptyalin breaks down complex carbohydrates into simpler sugars like dextrin and maltose.

Option A: Pepsin is a proteolytic enzyme found in the stomach, not in the saliva. It is responsible for breaking down proteins.
Option B: Renin is an enzyme secreted by the kidneys. It plays a role in regulating blood pressure and is not involved in digestion.
Option D: While a small amount of lingual lipase is present in saliva, its role is minor compared to ptyalin. The primary site for lipase activity (pancreatic lipase) is the small intestine, where it digests fats.

Visual 1: Diagram - An illustration of the major salivary glands (parotid, submandibular, sublingual) in the human head to show the source of saliva.
Visual 2: Flowchart - A simple flowchart showing the breakdown of starch by ptyalin into maltose in the oral cavity.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Digestive Enzymes in Saliva as background academic context rather than a clinical decision trigger.
Understanding the function of ptyalin is fundamental to comprehending the first step of carbohydrate digestion and overall nutrition.
Conditions that reduce saliva production (xerostomia or dry mouth), often seen in older adults or as a side effect of medications, can impair initial digestion and lead to dental caries and oral infections.
What if? - If a patient has Sjögren's syndrome, an autoimmune disease that damages salivary glands, the secretion of ptyalin would be significantly reduced. This would impair the initial digestion of carbohydrates in the mouth, potentially leading to difficulty swallowing and increased reliance on pancreatic amylase for carbohydrate breakdown in the small intestine.

How to Approach the Question

First, identify the core of the question: it asks for the specific enzyme found in saliva secreted by salivary glands.
Recall the basic process of digestion, which begins in the mouth.
Evaluate each option based on its primary location and function in the body.
Eliminate Pepsin, as it's a stomach enzyme for protein.
Eliminate Renin, as it's a kidney enzyme for blood pressure regulation.
Compare Ptyalin and Lipase. Recognize that ptyalin (salivary amylase) is the principal enzyme in saliva for carbohydrate digestion, making it the best answer.

Concept Tested & Keywords

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Practise the full RRB Staff Nurse Jaipur-6th June 2018

Attempt every question from this paper in a timed mock, then review the full solution for each one.