Study the diagram given below and then answer the questions that follow:

(a) Name the cells of the pancreas that produce (1) glucagon (2) insulin.

(b) State the main function of (1) glucagon and (2) insulin.

(c) Why is the pancreas referred to as an exo-endocrine gland?

(d) Why is insulin not given orally but is injected into the body?

(e) What is the technical term for the cells of the pancreas that produce endocrine hormones?

(f) Where in the body is the pancreas located?

(a) Glucagon is produced by alpha cells of Islets of Langerhans and insulin is produced by beta cells of Islets of Langerhans of the pancreas.

(b) The main function of glucagon is to increase blood sugar level by breaking down glycogen present in the liver to glucose.

The main function of insulin is to convert extra glucose into glycogen and store them in the liver. It also promotes glucose utilization by cells.

(c) Pancreas is referred to as an exo-endocrine gland because it behaves both as an exocrine and endocrine gland.

The pancreas contains special hormone-secreting cells called Islets of Langerhans which secretes hormones like insulin, glucagon, and somatostatin directly into bloodstream thus behaves as an endocrine gland. It also behaves as an exocrine gland by secreting enzymes which are carried through ducts and helps in digestion.

(d) Insulin is not given orally but is injected into the body because insulin is chemically protein in nature and thus it gets digested by protein digestive enzymes.

(e) The technical term for the cells of the pancreas that produce endocrine hormones is called Islets of Langerhans.

Islets of Langerhans has alpha, beta and delta cells which secrete glucagon, insulin, somatostatin respectively.

(f) Pancreas is located in the abdomen behind the stomach.