Modulation of Target Cell Sensitivity

Modulation of Target Cell Sensitivity - * Blood calcium...

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Endocrine System Modulation of Target Cell Sensitivity * Hormones affect only target cells * Cells that carry specific receptors that bind the recognized hormone * Down regulation- when receptor quantity decrease when hormone is in excess * Decreases responsiveness to hormone * Up regulation- when receptor quantity increases when hormone is deficient * Makes target cell more sensitive to hormone Receptor Down Regulation Clinical Application Blocking Hormone Receptors With Abortion Pill Control of Hormone Secretion * Most hormones are released in short burst, with little or know secretion in between. * Increased stimulation causes more frequent burst, thereby increasing blood concentration * Hormone secretion is regulated by * Signals from the nervous system * Chemical changes in the blood * Other hormones * Ex: nerve impulses to the adrenal medulla regulate the release of epinephrine
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Unformatted text preview: * Blood calcium regulates the release of parathyroid hormone * Adrenocorticotropic hormone from the pituitary gland stimulates the release of cortisol by the adrenal cortex Control of Hormone Secretion (cont) Disorders of the endocrine system often involve either * Hyposecretion- inadequate release of hormone * Hypersecretion- excessive release of hormone * Most cases are due to * Faulty control of secretion * Faulty hormone receptors * Inadequate number of receptors * Most hormonal regulatory systems work via negative feedback * Occasionally a positive feedback system contributes of regulation * In child birth, where oxytocin stimulates contractions of the uterus and the uterus in turn stimulates more oxytocin release....
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This note was uploaded on 01/30/2012 for the course BSC BSC1085 taught by Professor Sharonsimpson during the Fall '10 term at Broward College.

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