Insulin is a hormone produced by the beta cells in the pancreas. From beta cells, insulin enters the blood stream. It is thus transported to all cells of the body through the blood stream. There are cell receptors on the cell membranes onto which it is bonded. This bonding leads to biochemical processes that include.

  • Transferring the glucose, amino acids and certain ions from the membrane to the cell body.
  • Cells in liver, muscle and fat tissue absorb glucose present in blood and store it as glycogen.
  • Synthesis of protein RNA and DNA
  • Inhibition of gluconeogenesis
  • Degradation of glycogen and protein
  • The process of lipolysis

Insulin and diabetes
Insulin was first discovered in 1921 and is used to treat diabetes. Diabetes is a disease directly related and caused due to lack or resistance to this hormone. When the muscle and fat tissue cells do not respond to it, blood sugar level rises. This condition is seen in people with type 2 diabetes. Type 2 diabetes is sometimes treated with injections boosting the cell functions to reduce the blood sugar levels. In case of type 1 diabetes the pancreas makes very little or no insulin, causing the blood glucose levels to rise. In this condition, the hormone is injected to help utilise the blood glucose and thus reduce blood glucose levels.
Any mistake in administering the amount of dosage can lead to hypoglycaemia or hyperglycemia. When a diabetic person is given an insulin injection, there are a lot of factors that affect its absorption. These factors include:

  • Selecting the right dose, timing and mode of administration
  • Administering an appropriate preparation
  • Synchronising the timing of food intake and dosage while also deciding the proper amount and type of diet
  • Doing the required exercise with the advised dosage
  • Taking care of other illnesses and conditions like stress or depression if any

Injections, pens as well as pumps are the different devices that are used to inject insulin into a human body. The most common sites for injections are the abdomen, back of upper arms and at the outer site of thighs.

Types of insulin range from short to long acting ones, and, are given depending on the need of that particular individual, as each body responds differently to a different type.

There are five different types of insulin:

Rapid onset-fast acting insulin
Starts working within 1 to 20 minutes of administration. It is clear in appearance and most effective after one hour, lasting up to 3 consecutive hours.

Short acting insulin
It is injected half an hour before eating. It is clear in appearance and starts acting 30 minutes after being injected, and remains most effective for 4 to 6 hours thereafter.

Intermediate acting insulin
Its appearance is cloudy and effect lasts for as long as 16 to 24 hrs. Its starts acting 90 minutes after being injected.

Mixed insulin
It is cloudy and comprises of a combination of rapid onset fast acting or slow acting types with intermediate acting insulin.

Long acting Insulin
It does not have a specific peak time and works throughout the day.

The weight of your brain is 2% of your total body weight. Brain uses 20-25% of the oxygen you breathe, and it needs around 15% of the total blood supply