Bio1500 - Test 3 Notes

Bio1500 - Test 3 Notes - Control of Physiology by the Brain...

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a. b. c. Hypothalamus is part of brain that controls homeostasis 1. Way conscious part influences involuntary part a. Cortex acts thru limbic system to influence hypothalamus 2. Limbic involved in emotions 3. Conscious activity in cortex is funneled thru limbic to hypothalamus 4. AUTONOMIC NERVOUS SYSTEM (pp 991-2; 1068-69) a. b. ANS controls routine functioning of organs 1. Both operate automatically a. In these situations, hypothalamus activates symp i. b. Parasymp controls rest and digestion c. Actions of two systems are usually antagonistic d. ANS has 2 divisions: Sympathetic & Parasympathetic 2. ADRENAL MEDULLA Adrenal is an endocrine gland derived from ANS a. Epi is crucial when animal is in trouble b. In emergency or hi stress, Symp signal adrenal medulla to release epinephrine 1. a. b. But increased blud to skel muscle c. d. Strong activation of adrenal medullka causes: 2. Control of Physiology by the Brain Friday, March 14, 2008 10:14 AM Biology 1500 Page 1
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HORMONES (CH 45) Hormones are compounds released by cells and transported by blood & or extracellular fluid to affect target cells Production is controlled by horms i. Endocrine cells monitor levels of this product in their extracellular fluid ii. Output of hormone is adjusted to maintain a set level of the product iii. a. Horms control, organize much of physiology 1. Their targets are cell surface receptors i. Peptide hormones use this mechanism ii. Fast acting hormones cause effects in secs to mins; most common mechanism a. Hormones enter cell, binds to promoter region in DNA, affects transcription i. ii. iii. Slow acting hormones cause effects in hours to days b. Horms cause many actions but use 1 of2 mechanisms 2. Hormones are controlled by negative feedback 3. 1-2 mill clusters of cells scattered in pancreas i. In the Islets of Langerhans a. Alpha cells secret e glucagon which increases blood glucose b. High [glucose] > detected by beta cells > stimulates insulin secretion by beta cells > stimulates glucose facilitated transport into muscle and fat > lowers [glucose] in blood i. Low [glucose] in blood > detected by alpha cells > increases glucagon
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Bio1500 - Test 3 Notes - Control of Physiology by the Brain...

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