Briefly describe why the following symptoms of type I diabetes occur: a. Hyperglycaemia b. Polydipsia c. Polyuria d. Polyphagia

a. Hyperglycaemia: This occurs in type I diabetes because the body's immune system destroys the insulin-producing cells in the pancreas. Insulin is a hormone that helps glucose enter cells to be used for energy. Without insulin, glucose builds up in the bloodstream, leading to high blood sugar levels, or hyperglycemia.

b. Polydipsia: High blood sugar levels cause the kidneys to try to filter out the excess glucose. This process requires a lot of water, which leads to frequent urination. The loss of fluid from the body triggers the thirst response, causing the person to drink more than usual, a condition known as polydipsia.

c. Polyuria: As mentioned above, when blood sugar levels are high, the kidneys work to remove the excess glucose from the blood. This leads to increased urine production, a condition known as polyuria.

d. Polyphagia: When there is not enough insulin to help glucose enter cells, the body is unable to use glucose for energy. This triggers hunger signals, causing the person to eat more than usual, a condition known as polyphagia. Despite eating more, the person may still experience weight loss because the body starts breaking down stored fat and muscle for energy.