The Thyroid Gland
Anatomy of the thyroid gland
The thyroid gland is located in the front of the neck. It sits below the voice box
(larynx) and on top of the trachea (windpipe). The small, two-inch gland consists
of 2 lobes, 1 on each side of the windpipe, connected by a small bridge of thyroid
tissue called the isthmus.
The thyroid tissue is made up of 2 types of cells: follicular cells and parafollicular
cells. Most of the thyroid tissue consists of follicles lined by the follicular cells,
which secrete the iodine-containing thyroid hormones.
The hormones made by the thyroid consist of thyroxine (T4) and triiodothyronine (T3).
The parafollicular cells secrete the hormone calcitonin. In humans, calcitonin has
only a minor role in calcium regulation. These hormones are secreted by the thyroid
when our bodies needs them. The pituitary gland, found in our brain, helps regulate
this process. T3 and T4 increase you basal metabolic rate. They make all the cells
in the body work harder which effects things like body temperature, heart rate, bowel
function, and many more.
Functions of the thyroid gland
The thyroid plays an important role in regulating the body's metabolism. The hormones
it secretes help govern many functions of the body like how the body produces heat,
consumes oxygen and uses energy. Virtually every tissue in the body is affected or
regulated by thyroid hormone. It regulates the brain and nerve development and function,
skin, hair, eyes, heart, and intestine function. The thyroid hormones enter into tissues
and regulate how those tissues produce or don't produce certain proteins. The thyroid
function is controlled by the pituitary, which sits at the base of the brain. The
pituitary is controlled by a region in the brain called the hypothalamus. Thyroid
disorders usually occur from the thyroid producing either too much or too little hormone.