Chem - Ch. 20 Notes

Chem - Ch. 20 Notes - I. II. III. IV. V. Hormones and...

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I. Hormones and Neurotransmitters A. Hormones 1. Hormones arrive via the bloodstream 2. A chemical messenger secreated by cells of the endocrine system and  transported through the bloodstream to target cells with appropriate receptors  where it elicits a response 3. These responses require seconds to hours to begin, however their influence  lasts a long time and can be wide ranging B. Neurotransmitters 1. Neortransmitters arrive via nerve cells 2. A chemical messenger that travels between a neuron and a neighboring  neuron or other target cell to transmit a nerve impulse 3. Most nerve cells do not make direct contact with the cells they stimulate 4. Neurotransmitters are released in very short bursts and are quickly broken  down or reabsorbed by the nerve cell, their effects are typically short-lived II. Endocrcine system,  A. Control of hormone release B. A system of specialized cells, tissues, and ductless glands that excretes hormones and  shares with the nervous system the responsibility for maintaining constant internal body  conditions and responding to changes in the environment C. Direct Neural Control 1. A nervous system message from the hypothalamus initiates release of  hormones by the adrenal gland D. Direct Release of Hormones 1. Hormones move from the hypothalamus to the posterior pituitary gland,  where they are stored until needed E. Indirect Control Through Release of Regulatory Hormones 1. In the most common control mechanism, regulatory hormones from the  hypothalamus stimulate or inhibit the release of hormones by the anterior  pituitary gland. Many of these pituitary hormones in turn stimulate release of still  other hormones by their own target tissues III. Types of hormones:  A. Polypeptide 1. Polypeptide hormones are water-soluble molecules and so they cannot cross 
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This note was uploaded on 04/22/2008 for the course CHEM 13 taught by Professor Joseph during the Winter '07 term at UCSD.

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Chem - Ch. 20 Notes - I. II. III. IV. V. Hormones and...

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