Describe the function of the thyroid and the ovaries?
Answers: THYROID :
The primary function of the thyroid is production of the hormones thyroxine (T4), triiodothyronine (T3), and calcitonin. Up to 80% of the T4 is converted to T3 by peripheral organs such as the liver, kidney and spleen. T3 is roughly ten times more active than T4.
T3 and T4 production and deed
Thyroxine is synthesised by the follicular cells from free tyrosine and on the tyrosine residues of the protein call thyroglobulin (TG). Iodine is captured near the "iodine trap" by the hydrogen peroxide generated by the enzyme thyroid peroxidase (TPO) and coupled to the 3' and 5' sites of the benzene ring of the tyrosine residues on TG, and on free tyrosine. Upon stimulation by the thyroid-stimulating hormone (TSH), the follicular cells reabsorb TG and proteolytically cleave the iodinated tyrosines from TG, forming T4 and T3 (in T3, one iodine is gone compared to T4), and releasing them into the blood. Deiodinase enzymes convert T4 to T3. Thyroid hormone that is secreted from the gland is roughly speaking 90% T4 and about 10% T3.
Cells of the brain are a leading target for the thyroid hormones T3 and T4. Thyroid hormones play a particularly crucial role surrounded by brain development during pregnancy. A transport protein (OATP1C1) have been identified that seem to be important for T4 transport across the blood brain hurdle. A second transport protein (MCT8) is important for T3 transport across brain cell membranes.
In the blood, T4 and T3 are to a degree bound to thyroxine-binding globulin, transthyretin and albumin. Only a very small fraction of the circulating hormone is free (unbound) - T4 0.03% and T3 0.3%. Only the free fraction have hormonal activity. As beside the steroid hormones and retinoic acid, thyroid hormones cross the cell membrane and bind to intracellular receptors (α1, α2, β1 and β2), which feat alone, in pairs or together near the retinoid X-receptor as transcription factors to modulate DNA transcription
T3 and T4 regulation
The production of thyroxine and triiodothyronine is regulated by thyroid-stimulating hormone (TSH), released by the anterior pituitary. The thyroid and thyrotropes form a unenthusiastic feedback loop: TSH production is suppressed when the T4 levels are high-ranking, and vice versa. The TSH production itself is modulated by thyrotropin-releasing hormone (TRH), which is produced by the hypothalamus and secreted at an increased rate in situations such as cold (in which an accelerate metabolism would generate more heat). TSH production is blunted by somatostatin (SRIH), rising levels of glucocorticoids and sex hormones (estrogen and testosterone), and excessively big blood iodide concentration.
Calcitonin
An additional hormone produced by the thyroid contributes to the regulation of blood calcium level. Parafollicular cells produce calcitonin contained by response to hypercalcemia. Calcitonin stimulates movement of calcium into bone, in protest to the effects of parathyroid hormone (PTH). However, calcitonin seems far smaller quantity essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid, but not the parathyroids.
It may be used diagnostically as a tumor familiar sight for a form of thyroid cancer (medullary thyroid adenocarcinoma), in which giant calcitonin levels may be present and elevated level after surgery may indicate recurrence. It may even be used on biopsy sample from suspicious lesions (e.g. swollen lymph nodes) to establish whether they are metastasis of the artistic cancer.
Calcitonin can be used therapeutically for the treatment of hypercalcemia or osteoporosis.
OVARIES :
Besides Ovulation (Egg release and the related menstrual cycle),
Hormonal Functions:
Estrone (also oestrone) is an estrogenic hormone secreted by the ovary.
Estrone is one of the three estrogens, which also include estriol and estradiol. Estrone is the least prevalent of the three hormones, estradiol human being prevalent almost always within a female body, estriol self prevalent primarily during pregnancy. Estrone is relevant to health and disease due to its conversion to estrone sulfate, a long-lived derivative of estrone. Estrone sulfate act as a pool of estrone which can be converted as needed to the more active estradiol.
Please let off the perfunctory answer, but otherwise this would be too cumbersome. The Thyroid gland manufactures thyroid hormone which have a multitude of functions on metabolism as well as the cardiovascular system. The ovaries create oocytes for conception and also release estrogen until menopause. For a more detailed discussion, please consult a text on endocrinology or reproduction.
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