HormonesThe term hormone refers to the specific chemical messengers or "signaling molecules" secreted by glands in the endocrine system. Most familiar are the "endocrine hormones" which are released directly into the bloodstream to be carried to the cells which have protein receptors which can respond to them. There are also "exocrine hormones" which are released into a duct. These exocrine hormones may then enter the bloodstream or be conducted from cell to cell by diffusion (paracrine signaling). By these means, hormones are carried to essentially every part of the body and serve various regulatory functions.
References: Wiki Hormones
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Index Reference Audesirk & Audesirk Ch 32 Thibodeau & Patton Ch 16 | |||||||||||||||
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Description of HormonesThyroid Stimulating HormoneThe release of the thyroid hormones is stimulated by the thyroid-stimulating hormone (TSH) produced by the anterior lobe of the pituitary gland. The thyroid gland's release of thyroxine influences most cells in the body, increasing their metabolic rate and stimulating the synthesis of enzymes that break down glucose and provide energy. ThyroxineThe thyroid gland's release of thyroxine influences most cells in the body, increasing their metabolic rate and stimulating the synthesis of enzymes that break down glucose and provide energy. Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. It is the inactive form and most of it is converted to an active form called triiodothyronine by organs such as the liver and kidneys. Thyroid hormones play vital roles in regulating the body's metabolic rate, heart and digestive functions, muscle control, brain development and maintenance of bones. YourhormonesAntidiuretic Hormone (ADH)ADH acts to increase the permeability of the tubules in the nephrons of the kidney to release more water back into the bloodstream. This is a good example of homeostasis by use of a hormone to switch on permeability to retain water in the blood, and then ceasing the ADH when water needs to be excreted by the kidneys.
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Index Reference Audesirk & Audesirk Ch 32 Thibodeau & Patton Ch 16 | ||
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Go Back |