Page 79 - Biology_Form_3

Biology for Secondary Schools

iodine intake and regular screening memory loss, muscle weakness, bone pain,
for thyroid function can help in early kidney stones, and frequent urination.
detection and treatment. In some cases, The condition can lead to osteoporosis
autoimmune causes may not be preventable, which results from excessive calcium
but managing autoimmune responses can being released from bones, kidney stones,
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reduce the risk. and cardiovascular issues including
arrhythmias and hypertension. Primary
Hyperthyroidism hyperparathyroidism often cannot be
This occurs when the thyroid gland prevented, but regular monitoring of
overproduces thyroxine hormones. The calcium levels especially in people with
most common cause is Graves’ disease, an kidney disease or family history can aid
autoimmune disorder where the immune early detection. Surgery to remove the
system stimulates the thyroid gland to overactive parathyroid glands is often
overproduce the thyroxine hormone. necessary for treatment.
Other causes include toxic thyroid nodules
or inflammation of the thyroid gland. Goitre
Symptoms of hyperthyroidism include This is a disorder of the thyroid gland. It
weight loss, rapid heartbeat, sweating, occurs when the thyroid gland enlarges and
shakes, anxiety, and frequent bowel develops abnormally due to insufficient
movements. The disorder can result in iodine in the diet. A goitre can be visible
heart complications and osteoporosis, and as a lump or swelling in the neck region.
in severe cases, it can lead to a thyroid Figure 3.2 shows a person with goitre.
storm, a rare but life-threatening condition.
Preventing hyperthyroidism is difficult,
particularly for autoimmune causes.
However, early detection and treatment of
thyroid conditions can manage and mitigate
the risks associated with hyperthyroidism.

Hyperparathyroidism
This occurs when the parathyroid glands,
located near the thyroid, secrete too much
parathyroid hormone (PTH). This results
in high calcium levels in the blood. The Figure 3.2: A person with goitre
condition can be primarily caused by Goitre is associated with symptoms such
a tumour in the parathyroid gland or as lump formation in the neck, feeling
secondary caused by low calcium levels in tightness, scratch voice and difficulty in
the body, often as a result of kidney diseases swallowing.
and vitamin D deficiency. Symptoms of
the condition include fatigue, depression,

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