each of these is divided into a ventral and dorsal SCN. Albus found that the ventral SCN is relatively quickly reset by external cues‚ but the dorsal SCN is much less affected by light and more resistant to being reset. SCN sends signals to the pineal gland making it produce melatonin at night‚ melatonin creates sleep because it inhibits the brain mechanisms that promote wakefulness. 2. Describe in detail exogenous zeitgebers- resetting the biological clock (entrainment). Light resets the SCN‚
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endogenous clocks are slow (e.g. because the sun rises earlier than the day before) morning light automatically shifts the clock ahead‚ putting the rhythm back in sync with the day. At night‚ when there is no light‚ the SCN then sends a message to the pineal gland‚ causing it to increase the production of melatonin‚ which induces sleep by preventing the brains mechanism to promote wakefulness. An example of the way endogenous pacemakers control our circadian rhythms is a case study on Michael Siffre.
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cell‚ a gland‚ or an organ in one part of the body that affects cells in other parts of the organism. Hormones in animals are often transported in the blood. Cells respond to a hormone when they express a specific receptor for that hormone. Melatonin is a hormone found in animals‚ plants‚ and microbes. In humans‚ melatonin is produced by the pineal gland‚ a small endocrine gland located in the center of the brain but outside the blood–brain barrier‚ Production of melatonin by the pineal gland is inhibited
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We have an internal body clock the lasts the duration of a day (24 hours)‚ which is therefore able to control the circadian rhythm. As the biological body clock is controlled inside it is known as endogenous‚ these are called endogenous pacemakers. So how do these work on their own to affect the sleep-wake cycle and why do we need external factors to also help control our circadian rhythms? There have been many studies into endogenous pacemakers to see if our sleep-wake cycle (circadian rhythms)
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PARATHYROID GLANDS Parathyroid glands are small glands of the endocrine system which are located in the neck behind the thyroid. There are 4 parathyroid glands in the human body. Parathyroid glands control the calcium in our bodies – how much calcium is in our bones‚ and how much calcium is in our blood. Parathyroid glands secrete or make a hormone‚ called parathyroid hormone or PTH. The parathyroid glands measure the amount of calcium in the blood every minute of every day and if the calcium
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the adrenal medulla‚ which is in the inner adrenal gland. This gland sits atop the kidney. When put under stress this gland is stimulated by the nervous system and releases adrenaline into the blood stream. The release of adrenaline is a three step process. First‚ the hypothalamus produces hormones that stimulate the pituitary gland. Next‚ the pituitary gland then produces corticotropin hormones which are hormones that stimulate the adrenal glands that eventually produce adrenaline. In 1895
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BASIC CONCEPTS ENDOCRINE SYSTEM :- In physiology‚ the endocrine system is a system of glands‚ each of which secretes a type of hormone into the bloodstream to regulate the body. It derives from the Greek words endo meaning inside‚ within‚ and crinis for secrete. The endocrine system is an information signal system like the nervous system. Hormones are substances (chemical mediators) released from endocrine tissue into the bloodstream that attach to target tissue and allow communication among
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your brain called the pituitary gland‚ talk about a few symptoms one may have if their pituitary gland is not functioning as it should‚ and what type of tests are done to help solve these issues. So have you ever just felt off‚ not like yourself‚ sluggish or irritable? Well good news it is probably just the pituitary gland that is acting up like a wayward teenager. While I may make light of this‚ it could be something extremely serious. So what is this pituitary gland? According to the Society for
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thyroid gland is an integral part of the endocrine system in the human body. The thyroid gland secretes the thyroid hormone‚ which plays an important role in the growth of the body. The thyroid is butterfly shaped‚ and located at the bottom of the neck. Two important hormones produced by the thyroid gland are thyroxine and triidothyronine. Both of these hormones help the body grow after birth‚ and they also aid tissues increase their oxygen use within these tissues. The thyroid gland secretes
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The thyroid gland • • • • • anatomic considerations Formation and secretion of thyroid hormones Transport and metabolism of thyroid hormones Effects of thyroid hormones Regulation of thyroid secretion introduction: the thyroid gland • The thyroid gland maintains the level of metabolism in the tissues that is optimal for their normal function. • Thyroid hormones stimulate the O2 consumption of most of the cells in the body • Thyroid hormones help regulate lipid and carbohydrate metabolism • Thyroid
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