Digestion And Absorption

Step 1: Understanding the Role of Gastric Enzymes in Infants

- Prorennin is the inactive form of rennin present in the gastric juice of infants.
- Rennin is responsible for curdling milk by coagulating casein.
- Trypsin and Peptidase do not participate in milk digestion.

Step 1: Analyze Statement I:
Peptic cells (Chief cells) secrete proenzymes like pepsinogen and prorennin. Prorennin is activated to Rennin (chymosin), which is essential for milk digestion in infants. Thus, attributing rennin secretion to peptic cells is Correct.
Step 2: Analyze Statement II:
The liver is the primary site of the Ornithine cycle (Urea cycle), where ammonia is converted into urea for excretion. Correct.
Step 3: Analyze Statement III:
Steapsin is an older or alternative term used in biochemistry for Pancreatic Lipase, the principal fat-digesting enzyme. Correct.
Step 4: Analyze Statement IV:
The stomach is anatomically divided into Cardiac, Fundic, Body, and Pyloric parts. In many traditional biological contexts (and older NCERT versions), the stomach was broadly divided into Cardiac, Fundic, and Pyloric, where the Fundic region (often encompassing the body) was considered the main central part for storage and digestion. Based on the options provided, this statement is accepted as Correct.
Step 5: Conclusion:
All four statements are correct. Option (D).

- Paneth cells secrete lysozyme to fight microbes.
- Kupffer cells are liver macrophages.
- Intestinal lipase (steapsin) digests fats; 1 g fat yields ~9 kcal, not 4 kcal.
Hence, I and II are correct.

• Aminopeptidases are secreted by the small intestine and pancreas; statement I is partially correct.
• Ameloblasts secrete enamel during tooth development; statement II is correct.
• Human milk teeth formula = 2102/2102; statement III is correct.
• Liver is the largest gland but considered exocrine, endocrine function is minor; statement IV is incorrect.
• Hence correct statements: II, III.