Islets of Langerhans
Groups of pancreatic cells which make the hormones such as insulin which control the blood sugar levels.
Type 2 diabetes
The pancreas does produce insulin but cells stop responding properly to the insulin. It is often linked to obesity and lack of exercise and taking more exercise, losing weight and eating a carefully balanced diet can often control or even reverse type 2 diabetes.
Type 1 diabetes
Develops when the body does not produce the right amount of insulin or, in some cases, does not produce any at all. It must be treated with daily injections of insulin. People affected also need to manage their diet, eat regularly and plan exercise carefully to balance their energy needs with their food and insulin intake.
Immune system
The body's natural defence mechanism against infectious diseases.
Gene therapy
A new, experimental method of fighting disease by replacing a defective gene with a healthy gene
Blood sugar
The sugar (glucose) dissolved in the blood; the normal range is 4.0 - 7.8 mmol/l
Pancreas
An endocrine gland which produces insulin
Hormone
A chemical messenger produced by a particular gland or cells of the endocrine system. Hormones are transported throughout the body in the blood stream but they produce a response only in specific target cells
Protein
A polymer made up of amino acids joined by peptide bonds. The amino acids present and the order in which they occur vary from one protein to another.
Fibre
Material which cannot be digested in the gut, needed to provide bulk which enables food to move through the digestive system.
Liver
A large organ in the upper abdomen which manufactures, stores and breaks down substances as required by the body
Cell
The basic unit from which all living organisms are built up, consisting of a cell membrane surrounding cytoplasm and a nucleus.
Gene
A short piece of DNA which is responsible for the inheritance of a particular characteristic. It codes for the production of a specific protein. Genes occupy a fixed position, called a locus, on a particular DNA molecule.
Type 1 and Type 2 diabetes
There are two types of diabetes. In both, the body cannot regulate the level of glucose in the blood. This is because the body either stops producing the hormone insulin or does not respond properly to the insulin that is being made.
This model shows the structure of insulin. It is a complex protein hormone.
Image courtesy of: T. Blundell & N. Campillo / Wellcome Images
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Type 1 diabetes
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Type 2 diabetes
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Usually develops before the age of 20, with a peak at 12 years old.
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Usually appears after the age of 40.
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Pancreas stops making insulin.
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Pancreas makes reduced amounts of insulin, or the body does not respond normally to the insulin produced.
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Treatments include insulin injections, diet control and regular exercise.
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Treatments include diet control, medication and regular exercise.
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About 10% of diabetes cases.
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About 90% of cases.
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Also called insulin-dependent diabetes mellitus (IDDM)
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Also called non-insulin dependent diabetes
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| Symptoms: develop quickly. Tiredness, excessive urine production, weight loss, increased thirst and blurred vision. |
Symptoms: same as for type 1 but less severe and may go undetected for many years. |
What causes diabetes?
Diabetes does not have just one cause. Many factors influence whether a person develops diabetes or not. These include lifestyle, diet and genetic make-up.
Type1 diabetes
Injecting insulin allows diabetics to control their blood sugar levels.
Type 1 diabetes is an auto-immune disease. The person's immune system attacks the cells in the pancreas that make insulin. These cells are called the islets of Langerhans. The immune system destroys them as if they were an infection. Insulin production is quickly and dramatically stopped.
People with type 1 diabetes often have a particular form of a gene that is involved in the production of cell-recognition proteins. They trigger the immune system to destroy the insulin-producing cells.
It may soon be possible to develop a genetic test to identify people who are at a high risk of developing type 1 diabetes. It may even become possible to replace the faulty gene using gene therapy.
Type 2 diabetes
Obesity, and a lack of physical exercise, are linked to an increased likelihood of developing type 2 diabetes. It is more likely to develop if people have a diet that contains lots of saturated fats, sugar and is low in fibre. Some insulin production continues but the liver and body cells do not respond to it normally.
Question 1
Male aged 52 who is over weight and takes little exercise.
Girl aged 9 who has a history of diabetes in her family.