Question

What are beta cells of pancreas?

Answer 1

Hint: Pancreas is termed as a composite (heterocrine) gland. It works as both an exocrine and endocrine gland. The endocrine part of the pancreas is made up of over one million (i. e., about 1 to 2 million) patches of cells located around blood capillaries called Islets of Langerhans. These cover only 1 to 2% of the pancreatic tissue.

Complete answer:
The two main types of cells that are present in the Islet of Langerhans are called a-cells and B-cells which produce endocrine secretions
Now let us collect information about beta cells:
Beta cells ($\beta $-cells): These are also termed as $\beta $-cells. The B-cells synthesise a peptide hormone called insulin which regulates the glucose homeostasis. Insulin functions mainly on adipocytes (cells of adipose tissue), hepatocytes and muscle cells and enhances cellular uptake and utilisation of glucose. Whenever the level of glucose in the blood increases and rises, then $\beta $-cells of the pancreas get stimulated and synthesise insulin which increases:

1.Uptake of glucose by cells for respiration.
2.Uptake of glucose by liver and muscle cells for glycogenesis or conversion of glucose into glycogen.
3.Uptake of amino acids by cells and synthesis of proteins (effect on protein metabolism).
4.Fat synthesis in adipose tissue (effect on fat metabolism).

This would lead to decrease in the glucose concentration in blood and would increase rapid movement of glucose from blood to hepatocytes and adipocytes resulting in hypoglycemia (decrease in blood glucose level. Therefore, it could be observed that both glucagon and insulin help in homeostasis of glucose where both maintain the blood glucose level. When the glucose level get rises, then pancreas secretes insulin which causes glycogenesis and decreases the level of glucose in the blood but when the glucose level decreases in the blood, then pancreas secretes glucagon which causes glycogenolysis and gluconeogenesis and increases the level of glucose in the blood.

Note: Hyposecretion of insulin results in the presence of excess glucose in blood. This condition is known as hyperglycaemia. Prolonged hyperglycemia leads to a complex disorder called diabetes mellitus. This is characterised by loss of excess glucose through urine and also the formation of complex harmful compounds known as ketone bodies. As the glucose is excreted in the urine, water also moves out along with the glucose and causes excessive urination and dehydration of body tissues. Excessive thirst results in a condition called polydipsia.