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Unformatted text preview: 04/07/08 Chapter 33 Chemical Control of the Animal Body: The Endocrine System ~The Challenge~ Communication between the “50 million million” (50 trillion) different cells in your bodies By -> cell-to-cell contact (short distances) By -> hormone use (LONG distance) Hormones : • Chemicals secreted by cells in one part of the body, transported in bloodstream, exerting action to other body parts • Table 33-2 • Specific target cells have receptors found in one of two locations 1. Surface receptors on cell membrane These are water soluble but not lipid soluble and cannot cross cell membrane (peptide hormones and amino acid hormones) Hormones bind to protein receptors on cell surface, which causes a cascade of events utilizing a 2 nd messenger which transfers information from 1 st messenger (hormone) to target molecules in cell Textbook figure: (a) Amino acid and peptide hormones 2. Intracellular receptors Lipid soluble hormones that cross cell membrane easily through pores (steroids and prostaglandins) Combine with protein receptors in nucleus to produce a protein Textbook figure: (b) Steroid hormones • Maintain homeostasis 1. EX: insulin 2. Both negative (body temp.) and positive feedback (childbirth) Endocrine glands : •...
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This note was uploaded on 04/18/2008 for the course BIOL 1002 taught by Professor Pomarico during the Spring '08 term at LSU.
- Spring '08