The correct Answer is A-4, B-3, C-1, D-2
Explanation
The question pertains to the digestive system, specifically the stomach, and requires matching various gastric secretions and structures with their primary physiological roles. Understanding the functions of each component is crucial for comprehending the digestive process.
Statement-wise Analysis
- A. Hydrochloric acid (HCl):
- Correct Match: 4. Creates acidic medium
- Justification: Hydrochloric acid is secreted by the parietal (oxyntic) cells in the stomach. Its primary role is to create a highly acidic environment (pH 1.5-3.5) which is essential for the activation of pepsinogen into pepsin and for killing most bacteria ingested with food.
- B. Pepsin:
- Correct Match: 3. Facilitates protein digestion
- Justification: Pepsin is the chief proteolytic enzyme of the stomach. It is secreted in its inactive form, pepsinogen, by the chief (peptic) cells. The acidic environment created by HCl converts pepsinogen into active pepsin, which then breaks down proteins into proteoses and peptones.
- C. Mucus:
- Correct Match: 1. Protects inner lining of stomach
- Justification: Mucus is secreted by the goblet cells and mucous neck cells in the stomach. It forms a thick, protective layer over the gastric mucosa, shielding it from the corrosive action of hydrochloric acid and the proteolytic activity of pepsin. Bicarbonate ions trapped within the mucus layer further neutralize acid.
- D. Sphincter muscle:
- Correct Match: 2. Regulates release of food to small intestine
- Justification: The pyloric sphincter is a muscular valve located at the junction of the stomach and the duodenum (the first part of the small intestine). It controls the passage of partially digested food (chyme) from the stomach into the small intestine in a regulated manner, preventing rapid emptying and allowing for proper digestion and absorption in the small intestine.
Therefore, the correct matching is A-4, B-3, C-1, D-2.
Key Takeaway
The stomach's digestive functions rely on the coordinated action of hydrochloric acid for acidity, pepsin for protein breakdown, mucus for protection, and sphincter muscles for regulating food passage.