Class 11 · Chemical Coordination and Integration

Islets of Langerhans & Pancreatic Hormones — NEET Biology

📚 Practice Concept
📖 NCERT Source

Pancreas is a composite gland which acts as both exocrine and endocrine gland. The endocrine pancreas consists of 'Islets of Langerhans'. There are about 1 to 2 million Islets of Langerhans in a normal human pancreas representing only 1 to 2 per cent of the pancreatic tissue. The two main types of cells in the Islet of Langerhans are called α-cells and β-cells. The α-cells secrete a hormone called glucagon, while the β-cells secrete insulin.

NCERT Biology · Class 11 · Chapter 19 · Paragraph 23
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QuestionPractice Question

Assertion (A): The Islets of Langerhans contain two main types of hormone-secreting cells. Reason (R): The α-cells secrete insulin while the β-cells secrete glucagon.

📖 Solution & NCERT Explanation
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Correct answer: C If assertion is true but reason is false.

NCERT confirms “The two main types of cells in the Islet of Langerhans are called α-cells and β-cells” making the Assertion true. However, NCERT explicitly states “The α-cells secrete a hormone called glucagon, while the β-cells secrete insulin” - the Reason swaps these hormones making it false. This is a highly plausible error students commonly make.

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What does NCERT say about Pancreas composite gland which?
Pancreas is a composite gland which acts as both exocrine and endocrine gland. The endocrine pancreas consists of 'Islets of Langerhans'.
Has this concept appeared in NEET?
Practice this NCERT concept with questions on MedicNEET.
Which chapter is this from?
Chemical Coordination and Integration, Class 11 NCERT Biology.

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