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.
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.
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.
MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.