What is the role of the pancreas?

The pancreas is a pale gray gland which lies in the curve of the duodenum (apart of the digestive tract. Clusters of hormone-secreting cells known as the islets of Langerhans are located on the pancreas, which are one of two types of cells;

• Alpha cells, which secrete glucagon

• Beta cells, which secrete insulin
  

How does insulin work?

Insulin is a hormone which causes a decrease in blood glucose levels, and it occurs in a number of ways (processes).

• Through glycogenesis, the formation of glycogen from smaller glucose molecules for storage in the liver and in skeletal muscle

• Through lipogenesis, the formation of lipids from glucose for storage in adipose tissue

• Through protein synthesis, the formation of proteins from glucose

• Through translocation, the transport of glucose from the blood into body cells
  

The regulation of blood glucose via insulin occurs through a negative feedback system. Chemoreceptors in the beta cells of the islets of Langerhans stimulate the beta cells to secrete insulin. Blood glucose levels decrease, and hence the cells are no longer stimulated which halts production.

How does glucagon work?

Glucagon is a hormone which causes an increase in blood glucose levels, through a number of processes.

• Through glycogenolysis, the process of breaking down glycogen into glucose in the liver

• Through gluconeogenesis, the producing of new glucose molecules from lipids and amino acids in the liver

• Through lipolysis, which accompanies gluconeogenesis as lipids are required to be broken down for conversion into glucose
  

The regulation of blood glucose via glucagon occurs through a negative feedback system. Chemoreceptors in the alpha cells of the islets of Langerhans stimulate the beta cells to secrete glucagon. Blood glucose levels increase, and hence the cells are no longer stimulated which halts production.