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Thyroxine
Example Hormone Regulating
Metabolic Homeostasis
Thyroxine Hormone
Secreted by the thyroid gland
Structure contains four atoms of
iodine
The hormone targets ALL body
cells
Stimulates metabolism in the target
cells
increases metabolic rate
increases rates of protein
Thyroxine and Temperature Regulation
Chemoreceptors in hypothalamus sense
body temperature decreasing
Through a series of steps, the decrease in
body temperature causes the release of
thyroxine from the thyroid
Thyroxine triggers increased metabolism in
all body cells (chemical reactions in
cells)
Metabolism increases the generation of body
heat
Body warms.
Without thyroxine, metabolism is slower
lack of energy, feeling tired
forgetfulness and depression
weight gain
feeling cold
impaired brain development
What causes thyroxine deficiency?
The body does not make iodine, so it is an essential part
of your diet. Iodine is found in various foods.
If you do not have enough iodine in your body, you
cannot make enough thyroid hormone.
Thus, iodine deficiency can lead to enlargement of the
thyroid (goiter)
This has the effect of increasing the thyroid's ability to
trap more iodide, compensating for the iodine
deficiency and allowing it to produce adequate
amounts of thyroid hormone.
International Council for Control of Iodine Deficiency Disorders
(ICCIDD)
Add this information underneath the thyroxine
deficiency table in your notes
The ICCIDD is an international
non-governmental
organization with the
commitment to preventing
iodine deficiency.
The ICCIDD illustrates how
scientists cooperate and
collaborate to address
international concerns.
6.6.U2
Thyroxin is secreted by the thyroid gland to regulate the metabolic rate and help control
body temperature.
• Describe the structure and function of thyroxin.
• Outline thyroxin’s role in body temperature regulation.
• List symptoms of thyroxin deficiency.
D.5.NOS
Cooperation and Collaboration between groups of scientists – the International Council for the
Control of Iodine Deficiency Disorders includes a number of scientists who work to eliminate the
harm done by iodine deficiency.
• Outline consequences of iodine deficiency.
• State the goal of the ICCIDD.