Structure and function of thyroid gland pdf
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- Thyroid-Stimulating Hormone: Structure and Function
- Introduction to Thyroid: Anatomy and Functions
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Jump to content. The thyroid gland uses iodine from food to make two thyroid hormones: triiodothyronine T3 and thyroxine T4. It also stores these thyroid hormones and releases them as they are needed. The hypothalamus and the pituitary gland , which are located in the brain, help control the thyroid gland. The hypothalamus releases thyrotropin-releasing hormone TRH , which stimulates the pituitary gland to release thyroid-stimulating hormone TSH.
Thyroid-Stimulating Hormone: Structure and Function
Ides M. In thyrocytes, cell polarity is of crucial importance for proper thyroid function. Many intrinsic mechanisms of self-regulation control how the key players involved in thyroid hormone TH biosynthesis interact in apical microvilli, so that hazardous biochemical processes may occur without detriment to the cell. In some pathological conditions, this enzymatic complex is disrupted, with some components abnormally activated into the cytoplasm, which can lead to further morphological and functional breakdown. When iodine intake is altered, autoregulatory mechanisms outside the thyrocytes are activated.
Introduction to Thyroid: Anatomy and Functions
As it is known the endocrine system together with the nervous system enables other systems in the body to work in coordination with each other and protect homeostasis using hormones. Hormones secreted by the endocrine system are carried to target organs and cause affect through receptors. The thyroid gland is among the most significant organs of the endocrine system and has a weight of g. It is soft and its colour is red. This organ is located between the C 5 -T 1 vertebrae of columna vertebralis, in front of the trachea and below the larynx. It is comprised of two lobes lobus dexter and lobus sinister and the isthmus that binds them together Figure 1a.
The thyroid gland is made up of two cell types, follicular and parafollicular cells. The follicular cells are responsible for producing thyroid hormones. The follicular cells enclose a space called the colloid which contains stored thyroglobulin, a glycoprotein that contains the precursors T3 and T4.
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The thyroid , or thyroid gland , is an endocrine gland in the neck consisting of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thyroid is located at the front of the neck, below the Adam's apple. Microscopically, the functional unit of the thyroid gland is the spherical thyroid follicle , lined with follicular cells thyrocytes , and occasional parafollicular cells that surround a lumen containing colloid. The thyroid gland secretes three hormones: the two thyroid hormones — triiodothyronine T 3 and thyroxine T 4 — and a peptide hormone , calcitonin.
NCBI Bookshelf. The thyroid gland is a vital hormone gland: It plays a major role in the metabolism, growth and development of the human body. It helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream. If the body needs more energy in certain situations — for instance, if it is growing or cold, or during pregnancy — the thyroid gland produces more hormones. This organ medical term: glandula thyreoidea is found at the front of the neck, under the voice box.
The thyroid gland is a butterfly-shaped organ located in the base of your neck. It releases hormones that control metabolism—the way your body uses energy. The thyroid's hormones regulate vital body functions, including:. The thyroid gland is about 2-inches long and lies in front of your throat below the prominence of thyroid cartilage sometimes called the Adam's apple. The thyroid has two sides called lobes that lie on either side of your windpipe, and is usually connected by a strip of thyroid tissue known as an isthmus. Some people do not have an isthmus, and instead have two separate thyroid lobes.
In this article, we will be looking at its anatomy, its cellular structure, its endocrine physiology and its clinical relevance. It is roughly butterfly-shaped, with two lobes wrapping around the trachea and connected in the middle by an isthmus. The thyroid gland is not usually palpable. It is supplied by superior and inferior thyroid arteries, drained via superior, middle and inferior thyroid veins and has a rich lymphatic system. You can read more about the anatomy of the Thyroid gland here. Fig 1 — Anterior view of the neck, showing the anatomical position of the thyroid gland.