BIOL 112 1st Edition Lecture 22 Outline of Last Lecture I Breathing Control II Oxygen Sensitivity III The Kidneys Outline of Current Lecture IV Intro to Hormones V Glands VI Cellular Response to Hormones VII cAMP Current Lecture I Intro to Hormones It s essential that cells are able to communicate and coordinate with each other This is achieved in 3 ways Local Systems one cell communicates with other cells and itself Nervous System one cell communicates with 1 other cell individual communication requires cells to be really close together These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Hormone System one cell communicates with many cells mass communication a chemical is released from the cell regardless sending a signal Hormone A chemical secreted into body fluids by one cell or a group of cells which exerts a physiological control effect on other cells in the body two types Peptides small chains of amino acids Steroid lipids all cholesterol derivatives II Glands clusters of epithelial cells specialized for secretion Two types Exocrine Glands have ducts secretions are released to the outside of the body i e pancreas salivary sweat no hormones released Endocrine Glands no ducts secretions are released into body fluids i e pituitary thyroid hormones are released Each cell in the gland is specialized to make only one hormone type Peptide have well developed rough ER Steroid have well developed smooth ER III Cellular Response to Hormones Target cells or tissues effected by cells over which a particular hormone has its physiological control response differs depending on whether the hormone is peptide or steroid has specific receptors to hormone Cellular response to steroid hormone is relatively slow can take hours Cellular response to peptide hormone peptide hormone is hydrophilic and therefore cannot easily pass through the plasma membrane the receptor must be on the outer surface of the cell and there must be some mechanism to communicate presence of hormone into the cell cellular response is relatively rapid can take seconds to a few minutes rapid response is achieved because the system activates proteins that are already present and does not require synthesis of new proteins IV cAMP Second Messenger stimulates activates various enzymes kinases for example alteration in cell permeability to various molecules muscle contraction or relaxation protein synthesis stimulation release of secretions from gland cells Destruction of cAMP molecule is hydrolyzed by phosphodiesterase Protein transduction array responds to cAMP activation by activation of enzymes frequent mechanism involves kinases working in a phosphorylation chain reaction Self Regulation cell automatically shuts down response unless hormone is constantly present and bound to receptor
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