Thyroxin (sometimes written "thyroxine")
is a hormone sectreted by the thyroid
gland - which is an endocrine
gland in the
human body - click here for a diagram of the locations in the body
of the endocrine glands.
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Functions
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Thyroxin is important for the regulation of the body's
Basal
Metabolic Rate (BMR), which is the amount of energy
the body uses, just to ‘tick over’.
The consequences
of both excessive quantities of thyroxin in the body (hyper-thyrodism),
and insufficient thyroxin in the body (hypo-thyroidism), are
summarised below:
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Hyper-Thyroidism = ‘over-active
thyroid’ = Thyrotoxicosis
Symptoms: increase in BMR; increase in heart-rate; loss of weight; hyper-activity;
insomniac; develops bulging eyes due to accumulation of fluid behind the eye;
may develop Goitre; possible link with Attention Deficit Disorder. |
Hypo-Thyroidism
Symptoms; decrease in BMR; weight gain; lethargy; skin becomes dry and puffy;
hair becomes thin and brittle.
Causes: Derbyshire Neck (originally due to insufficient iodine
in the soil in Derbyshire), Graves Disease, and Cretinism (=
metal and sexual development imapaired, if occurs in children).
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For further general/summary information (excellent for revision !) visit
the page about
Endocrine
Glands of the Human Body.
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