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Subject - physiology

The thyroid gland (glandula thyreoidea) is an endocrine gland found in all vertebrates. In humans, it is the largest hormone gland and is located in the lower neck area. It consists of many gland follicles, in which the thyroid hormone is found and which are surrounded by a dense network of blood capillaries.

Fig.1
L-Thyroxine

The thyroid produces the hormones triiodothyronine and tetraiodothyronine (thyroxine), whose physiological effect is a general activation of the basal metabolic rate through stimulation of the carbohydrate, protein, and solid metabolism. After biosynthesis, the thyroid hormones are first bound to a globular protein within the follicles, where they are stored as thyroglobulin until their release into the bloodstream is triggered by the pituitary hormone thyrotropin. Both under-activity (hypothyroidism) and over-activity (hyperthyroidism) of the thyroid lead to pathological changes. To the side and toward the back of the thyroid lies the tissue of another independent endocrine gland, the parathyroid gland.

Fig.2
Thyroid gland (german)
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