The thyroid, rather than being a separate "part" of the endocrine
system is a major player of the whole endocrine system which regulates
metabolism, growth, development and puberty, tissue function and moods.
It does this by secreting thyroid hormones that regulate the speed in
which body's chemical functions proceed (metabolic rate).
Technically speaking, the thyroid gland regulates or in some way participates in the process of the following 14 body functions:
- regulates basal metabolic rate
- regulates body temperature
- regulates appetite
- promotes expulsion of glucose for energy
- stimulates protein synthesis
- increases lipolysis
- regulates cholesterol levels
- maintains standards for cardiac function
- promotes normal neuronal development in
the fetus and infants
- promotes normal neuronal function in
adults
- enhances effects of sympathetic nervous
system
- promotes body and skeletal growth
- promotes development of muscles and
muscle function
- regulates standards for female
reproduction and lactation
For as small as the thyroid is in physical size, it does quite a bit for our bodies. So just how does it do all this?
The
thyroid gland is located in the front of your neck just below the Adams
Apple. It is wrapped around the trachea (windpipe) and has a shape
similar to that of a bow tie or butterfly. Its only purpose is to
produce hormones which are introduced through the blood effecting
metabolism throughout our entire body. The thyroid gland produces its
two most important thyroid hormones, thyroxin (T4) and triiodothyronine
(T3), from iodine which it gets from a diet of seafood and salt.
Although the thyroid produces more T4 than T3 hormones (approximately
10:1 ratio) the T3 hormone is the more biologically potent of the two.
Once introduced into the blood from the thyroid gland, a large portion
of the T4 hormone is then converted into T3 hormone. The T3 hormone is
the actual hormone affecting the body's metabolism.
The thyroid
gland works in conjunction with two other glands, the hypothalamus gland
(the area of the brain that controls body temperature, hunger and
thirst) and the pituitary gland, located at the base of the brain, which
acts as a regulator to the output of the thyroid glad. Hormones
produced from each gland signals the next gland to produce its hormone.
So the hypothalamus gland produces a hormone called TRH which sends a
signal to the pituitary gland to produce a hormone called TSH which in
turn signals the thyroid to produce T4 and T3 hormones. In addition to
the signal from the TRH hormone from the hypothalamus gland, the
pituitary gland senses the levels of T4 and T3 hormones in the blood and
signals the thyroid gland by the amount of TSH hormone it releases to
either increase or decrease the production of T4 and T3 hormones.
Because
of the wide influence the thyroid has to the rest of the body, it is
essential that the thyroid be kept in good health at all times. A
dysfunctional thyroid can escalate, causing further dysfunction and
damage to other organs of the body, and in some cases, if left
unattended, a dysfunctional thyroid can become fatal with a heart attach
By
Dennis Earle