Читать книгу Diabetes For Dummies - Рубин Алан Л. - Страница 17

You don’t see your pancreas very often, but you hear from it all the time. It has two major functions. One is to produce digestive enzymes, which are the chemicals in your small intestine that help to break down food. The digestive enzymes don’t have much relation to diabetes. Your pancreas’s other function is to produce a hormone of major importance, insulin, and to secrete it directly into the blood. The following sections explore the ins and outs of your pancreas and insulin so that you’re well acquainted with both.

Examining your pancreas

Figure 3-1 shows the microscopic appearance of the pancreas. The following list explains the different cells found in the pancreas as well as their functions:

✔ B cells: The insulin-producing pancreas cells (also called beta cells) are found in groups called Islets of Langerhans.

✔ A cells: These cells produce glucagon, a hormone that’s very important to people with diabetes because it raises blood glucose when the glucose level gets too low. A cells are present in the Islets of Langerhans.

✔ D cells: These cells make somatostatin (a hormone that blocks the secretion of other hormones but doesn’t have a use in diabetes because it causes high blood sugar and increased ketones by blocking insulin as well). Like the cells described above, D cells are also found in the Islets of Langerhans.

Illustration by Kathryn Born

Figure 3-1: The pancreas and its parts.

Understanding insulin

If you understand only one hormone in your body, insulin should be that hormone (especially if you want to understand diabetes). Over the course of your life, the insulin that your body produces or the insulin that you inject into your body (as I describe in Chapter 11) affects whether or not you control the glucose levels in your blood and avoid the complications of the disease.

Think of your insulin as an insurance agent who lives in San Francisco (which is your pancreas) but travels from there to do business in Seattle (your muscles), Denver (your fat tissue), Los Angeles (your liver), and other places. This insulin insurance agent is insuring your good health.

Wherever insulin travels in your body, it opens up the cells so that glucose can enter them. After glucose enters, the cells can immediately use it for energy, store it in a storage form of glucose (called glycogen) for rapid use later on, or convert it to fat for use even later as energy.

After glucose leaves your blood and enters your cells, your blood glucose level falls. Your pancreas can tell when your glucose is falling, and it turns off the release of insulin to prevent hypoglycemia, an unhealthy low level of blood glucose (see Chapter 4). At the same time, your liver begins to release glucose from storage and makes new glucose from amino acids in your blood.

If your insurance agent (insulin, remember? – stick with me here!) doesn’t show up when you need him (meaning that you have an absence of insulin, as in type 1 diabetes) or he does a poor job when he shows up (such as when you have a resistance to insulin, as in type 2 diabetes), your insurance coverage may be very poor (in which case your blood glucose starts to climb). High blood glucose is the beginning of all your problems.

Doctors have proven that high blood glucose is bad for you and that keeping the blood glucose as normal as possible prevents the complications of diabetes (which I explain in Part II). Most treatments for diabetes are directed at restoring the blood glucose to normal.