Insulin is a
protein hormone secreted by the Beta Cells of the Islets of the Langerhans
within
the pancreas (an
endocrine gland in the human body).
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Insulin is extremely important for the regulation of
the amount of sugar (glucose) in the blood.
The secretion of insulin by the Beta Cells of the pancreas is stimulated
by (high) concentration
of blood sugar. The insulin secreted prevents the amount of sugar
in the blood from rising to a dangerous level by acting in many
ways, including:
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Easing and increasing the rate of diffusion of glucose
from the blood into most of the body cells - especially the
skeletal muscle fibers.
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Accelerating the conversion of glucose into glycogen and
fatty acids. |
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Promoting the uptake of amino acids into body cells and
increasing the production of proteins within cells. |
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Reducing the rate of conversion of liver glycogen into glucose.
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Reducing the rate of formation of glucose by liver cells.
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Conversely, when
blood sugar levels fall to below the typically "normal" level
i.e. in the range 4-10 m.mol/litre, another hormone called glucagon increases
the quantity of glucose in the blood. |
Insufficient or "hypo-" insulin gives rise to diabetes
mellitus.
Symptoms include: Blood
glucose levels rise (hyperglycaemia). Glucose is excreted into the urine
(glycosuria) - which increases levels of urination, causing dehydration.
As glucose levels in the blood increase, fat and protein are broken-down
for
energy.
Coma and death may follow if the symptoms are not treated.
For more information about the way the body balances blood sugar levels,
see the page about diabetes. For further general/summary information
(excellent for revision !) visit the page
about Endocrine
Glands of the Human Body. |
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