Equipping People To Make Sense Of What They Are Told
Hormone - a chemical released by one or more cells that affects cells in other parts
of the organism, only a small amount of hormone is required to alter cell metabolism.
It is essentially a chemical messenger that transports a signal from one cell to
another.
Cells respond to a hormone when they express a specific receptor for that hormone.
The hormone binds to the receptor protein, resulting in the activation of a signal
transduction mechanism that ultimately leads to cell type-specific responses.
Endocrine hormone molecules are secreted (released) directly into the bloodstream.
Exocrine hormones (or ectohormones) are secreted directly into a duct, and from the
duct they either flow into the bloodstream or they flow from cell to cell by diffusion
in a process known as paracrine signalling.
The liver does not produce hormones itself, the liver has a role in hormonal imbalances
because it breaks down or metabolises the hormones once they have done their work
in the body.
Thyroxine (T4) - the main hormone made by the thyroid gland, containing 4 iodine
molecules.
Triiodothyronine (T3) - a hormone with 3 iodine molecules, made in small amounts
by the thyroid gland and in larger amounts from T4 in other body tissues
