Download Dear «PrefName» «Surname» this work is due in 7 days from 6/10

Dear «PrefName» «Surname» this work is due in 7 days from 13/05/2017
Please read the following discussion
and answer the questions on the next
page.
Diseases of the Endocrine System
It is unlikely that you think about
your endocrine system as you go
about your daily lives. However, it is
a system that affects almost every
cell, organ, and function in your
body. The endocrine system regulates
mood, growth and development,
metabolism, and reproductive
processes.
Sometimes the endocrine system does
not function correctly and this causes
diseases such as hyperthyroidism,
hypothyroidism, Addison’s disease
and Cushing’s disease.
Hyperthyroidism
Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone. The prefix
hyper means above. Thyroid hormone affects nearly every tissue in the body and controls the rate of
metabolism. When there is too much thyroid hormone, all the functions of the body tend to speed up.
The effect of this is for the person to feel nervous, anxious and irritable. They perspire more than
normal, feel as though their heart is racing and experience hand tremors and muscular weakness.
People with hyperthyroidism may lose weight even though they have a good appetite and eat well.
Hypothyroidism
Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormone.
The prefix hypo means below. The thyroid gland uses iodine to produce thyroid hormones. A lack of
iodine (naturally available from seafood) in the diet may be the cause of the problem.
The symptoms of hypothyroidism are not specific, making it difficult to diagnose the condition
in its early stages. The symptoms may mimic other diseases as well as some of the normal changes to
the body caused by ageing. Once the disease progresses, the symptoms become more obvious.
Common symptoms are fatigue, depression, some weight gain, intolerance of cold and sleepiness.
Most of these are caused by a slowing of the body’s metabolism.
As the disease progresses, the heart rate slows down and the body temperature falls. These
symptoms can lead to heart failure. When hypothyroidism is diagnosed correctly, it can be treated
easily with pills to replace the thyroid hormone.
Addison’s disease
Addison’s disease is a rare disease that affects men and women of all ages. It is caused by a lack of
the hormone cortisol normally produced by the adrenal glands. The cause of the problem may be that
the adrenal glands cannot produce the cortisol for some reason, or it may be that the pituitary gland
does not send the necessary signal to the adrenal glands.
The symptoms of Addison’s disease may include: weakness, fatigue, weight loss and depression.
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Cushing’s disease
Cushing's disease is caused by the over-production of cortisol by the adrenal glands. It is a rare
disease occurring in only about one in about ten thousand people. The symptoms include having an
excessive amount of fat stored around the waist, insulin resistance, high blood pressure, osteoporosis,
kidney stones and frequent and excessive mood swings.
Questions
1
a Identify the relationship between hypothyroidism and hyperthyroidism.
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b Compare this to the relationship between Addison’s disease and Cushing’s disease.
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2
Use your knowledge of metabolism to work out why weight loss is a common symptom of
hyperthyroidism.
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3
Hypothyroidism was commonly diagnosed in people who lived a long way from the sea. Suggest
why this relationship occurred.
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4
Iodised salt is available in supermarkets and is used as table salt. This is normal salt that has
iodine added to it. Propose why iodine has been added to salt.
...........................................................................................................................................
5
Compare the symptoms of hypothyroidism and Addison’s disease.
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6
Deduce why diseases of the endocrine system are difficult to diagnose.
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