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 the Alpha cells of the islets of Langerhans.
Insulin is produced by the Beta cells of the islets of Langerhans.

(b) The main function of Glucagon is to raise the blood glucose levels by stimulating the breakdown of glycogen to glucose in the liver.
The main function of Insulin is to maintain the levels of glucose (sugar) in the blood.

(c) Exocrine glands are those glands which deliver their secretions to the target through ducts. An endocrine gland is one which does not pour its secretions into a duct but directly into the blood. As an exocrine gland the pancreas secrete pancreatic juices into the duodenum for digestion. As an endocrine gland, it has special groups of hormone-secreting cells called Islets of Langerhans which are scattered in the entire gland. The islet cells produce three hormones — insulin, glucagon and somatostatin which are poured directly into the blood. Hence, the pancreas is an exo-endocrine gland.

(d) Insulin is not administered orally because the digestive juices degrade insulin making it ineffective. Hence, to avoid its degradation, Insulin is injected into the body.

(e) Islets of Langerhans

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