Thyroid Stimulating Hormones – TSH stimulate the thyroid to produce the thyroid hormones. TSH is one of the six hormones produced by the anterior pituitary. The growth hormone – GH or Somatotropic Hormone promotes skeletal and muscular growth by stimulating the rate at which amino acids enter cells and protein synthesis occurs. It also promotes fat metabolism as opposed to glucose metabolism, the amount of growth hormone produced by the anterior pituitary during childhood affects the height of an individual. Too much can cause gigantism, while an insufficient amount result in limited stature and even pituitary dwarfism. So this GH is produced by the anterior pituitary quantity being greatest during childhood and adolescence, like when most body growth is occurring.
The thyroid gland is composed of a large number of follicles, each a small spherical structure made of Thyroid cells filled with Triiodothyroxine – T3 which contains 3 iodine atoms and Thyroxine – T4 which contains 4. Interesting huh? To me it was . . . very for that matter. To produce T3 & T4, the Thyroid Gland actively, acquires iodine. The concentration of iodine in the Thyroid Gland can increase to as much as 25x that of the blood. If the iodine lacks in the diet, there is inability of the Thyroid Gland to produce the Thyroid hormones. In response to constant stimulation by the Anterior Pituitary, the Thyroid enlarges – Goiter.
Thyroid hormones increase the metabolic rate. They do not have a target organ; instead they stimulate all cells of the body to metabolize at a faster rate. More glucose is broken down and more energy utilized. If the thyroid fails to develop properly, Congenital Hypothyroidism results. Short & stocky stature. Thyroid hormone therapy can initiate growth, but unless treatment is begun within the first 2 months of life, mental retardation results. Overactive thyroid = exophthalmic goiter, Eyes protrusion, Hyperactivity, nervousness, irritability & insomnia.
Enter some vocabulary Calcitonin – Ca2+. It plays a significant role in both nervous conduction and muscle contraction. It is also necessary for blood clotting. The blood Ca2+ level is regulated in part by this hormone that is secreted by the thyroid gland when the blood Ca2+ level rises. The primary effect of Ca2+ is to bring about the deposit of Ca2+ in the bones. So if the thyroid goes hyper/ lazy, Calcitonin too, Calcium too and finally bones too. It also temporarily reduces the activity and number of Osteoclasts. When the blood Ca2+ level lowers to normal, the release of Calcitonin by the thyroid is inhibited but a low level stimulates the release of parathyroid hormone – PTH by the parathyroid glands . . . and so on and so forth.
End of the mini bio class!!!
By S. S. Mader