Download Review: purpose of the endocrine system endocrine glands

Review:
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purpose of the endocrine system
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endocrine glands
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hormones produced and their purpose
Oct 11­10:27 AM
Negative Feedback Loop
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a process that detects and reverses changes from normal body constants (homeostasis)
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involves a receptor (ex. sensory organ), an integrator (ex. hypothalamus) and an effector (ex. gland)
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an example would be the hypothalamus ­ pituitary complex
Oct 11­10:31 AM
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Example of Negative Feedback Loop
Hypothalamus­pituitary complex
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the hypothalamus is the part of the brain that controls the endocrine system
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this is due to its control of the pituitary gland (the master gland)
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the pituitary gland has two parts: the anterior pituitary (front) and the posterior pituitary (back) see page 428
Oct 11­10:38 AM
Positive Feedback Loop
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often associated with disease or change (ex. drug addiction) and thus is often rare
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acts to increase the stimuli and in the case of drugs push the body away from homeostasis
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an exception is use of oxytocin, a hormone that causes contractions during childbirth
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each contraction causes the release of more oxytocin until the child is born
Oct 11­10:34 AM
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Negative Feedback Mechanism
Hypothalamus
Releasing Factor (Hormone 1)
Pituitary
Gland
Feedback
(excess hormone levels)
inhibits release
of hormone 1
Stimulating Factor
(Hormone 2)
Feedback
inhibits release
of hormone 2
Target Gland
Target Hormone Released
Oct 14­10:18 AM
Positive Feedback Mechanism (Oxytocin Loop)
Uterine water
breaks
Pressure Exerted on Cervix
Uterine Contractions Increase
Increase Oxytiocin Released
Oct 14­10:30 AM
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Antagonistic Hormones
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hormones that work against each other or have opposite effects on the body
Ex.
insulin and glucagon
parathyroid hormone and calcitonin
Tropic Hormones
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hormones that regulate the hormone production of many other hormones
Readings:
Pages 427 ­ 435
Oct 14­2:56 PM
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