Sometimes friction on the skin--from clothing, for example--will cause a hair follicle to swell up. This can make the opening close up, trapping the bacteria inside and starting an infection. Boils and carbuncles often form in moist areas of the body such as the back of the neck, buttocks, thighs, groin, and armpits. If you have a chronic illness, such as diabetes or kidney or liver disease, you may be more likely to have boils and carbuncles.
Islets of Langerhans. The islets of Langerhans are the endocrine (endo= within) cells of the pancreas that produce and secrete hormones such as insulin and glucagon into the bloodstream. The pancreatic hormones, insulin and glucagon, work together to maintain the proper level of sugar (glucose) in the blood. Blood sugar is used by the body for energy. An understanding of the two functional components of the pancreas is important for two reasons.
Your pancreas produces insulin and glucagon, two hormones that regulate sugar levels in your blood. Insulin and glucagon are secreted from your pancreas directly into your blood. When the concentration of glucose (a sugar) rises in your blood, insulin is released. Insulin lowers blood glucose levels by stimulating cells throughout your body to use and store glucose. Glucagon has the opposite effect of insulin.