Endocrine notes

Endocrine notes - Bodys second great controlling system...

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Body’s second great controlling system (first is nervous) Reproduction Growth and development Mobilization of bosy’s defenses Hormones Chemical substance secreted by cells into extracellular fluids Regulate metabolic function of other cells Lag time ranging from seconds to hours Endocrine glands (ductless glands) Pituitary Thyroid Parathyroid Pineal Pancreas Gonads Hypothalamus (in brain) Majority of hormones are amino acid based Amines, Thyroxine, Peptides, protein hormones Other types include steroids like gonadal and adrenocortical and eicosanoids which include leukotrines and prostaglandins Produce 1 or more of the following cellular changes Alter cell membrane permeability Stimulate protein synthesis Activate or deactivate enzyme systems Induce secretory activity Stimulate mitosis Can use secondary messengers which either use regulatory G-proteins or amino acid based hormones (depends of type of target cell and type of protein systems) cAMP rapidly degrades by phosphodisterase (acts only for a short period of time to activate protein kinases Precise response of steroid hormones depends on the type of target cell In order to be a target cell, has to have a certain type of receptor to which hormone binds Depends upon Blood levels of hormone Has to be relative number of receptors on the arget cell sensitive to this type of hormone Can work in either upregulatory or downregulatory mechanisms
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Rate at which the hormone is being released into bloodstream Speed of degradation of that hormone Hormones are removes by degrading enzymes, kidneys, and liver Permissiveness- one hormone can only exert its full effects in another hormone is present Synergism- more than 1 hormone affects the target cell and the effect is amplified
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This note was uploaded on 02/09/2012 for the course BIO 102 taught by Professor William during the Spring '11 term at Harvard.

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Endocrine notes - Bodys second great controlling system...

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