CGPwned EXTRA - BIO F214 - Diabetes

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Diabetes mellitus is a disease in which the body is no longer able to control its blood glucose
concentration, leading to very high concentrations.
Type I diabetes (insulin ­ dependent diabetes) usually starts in childhood. It is thought to be
the result of an autoimmune response in which the body's own immune system attacks the
cells and destroys them. It may also result from a viral attack.
Interestingly, experiments on identical twins suggest that
environmental factors might influence the expression of the
genes that eventually lead to the onset of the disease (only
one twin had the disease ­ the other did not, despite both
having the same genome).
The loss of cells means that high blood glucose levels
cannot be detected, and as a result, there is no secretion of
insulin into the body, hence, body cells cannot respond to high
blood glucose levels by absorbing glucose into the cytoplasm
and storing it as glycogen.
Type II diabetes (non ­ insulin ­ dependent diabetes) can still produce insulin, however, the
responsiveness to insulin declines. This may be because the specific insulin receptors on the
surface of body cells change shape or become removed due to increased stimulation from
insulin as a result of high blood glucose levels which causes cells to initially secrete the
insulin. As a result, there are less insulin receptors per cell that can accept insulin molecules
into its binding site, and as a result, the level of responsiveness to insulin decreases. Hence,
less glucose is absorbed into body cells. The levels of insulin secreted may also decline
perhaps. Certain factors seem to bring an earlier onset of type II diabetes, including:
A diet high in sugars, particular refined sugars
Being Asian or Afro-Caribbean origin
Family history
Effects of diabetes include:
Frequent urination as high blood glucose levels draw water out of body cells by
osmosis; and the fact that the kidneys work harder to filter out excess glucose.
Increased thirst as a result of loss of water in body cells, which is detected in the
hypothalamus, leading to the triggering of thirst centres.
Increased risk of kidney failure because the kidneys are working harder to filter out
excess glucose.
Increased risk of becoming blind ­ called diabetic retinopathy, which is caused by
damage to blood vessels in the retina. Hyperglycemia activates special kinases that
result in the apoptosis of cells called pericytes which help maintain the formation of
the blood-retinal barrier.

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Increased hunger because the body cells aren't absorbing the glucose, hence, despite
the high blood glucose levels, cells aren't metabolising it to produce ATP
Weight loss since the body cells cannot metabolise the glucose, they start
metabolising lipids for ATP as the body's glucose reserves are needed to supply brain
Depression as a possible result of neurological changes in the brain caused by reduced
glycemic control.…read more


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