Endocrine System.docx - Endocrine System Endocrine sys...

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Endocrine System Endocrine sys responsible for secreting hormones + other molecules that help regulate entire body Neuroendocrine control center - hypothalamus + pituitary gland Hormone secretion triggered by variety of signals o Hormonal signs o Chem reactions o Environmental cues Key in the lock model o Only cells w certain receptors can benefit from hormonal influence Steroid hormones - trigger gene activation + protein synthesis in target cells Protein hormones - change activity of existing enzymes in target cells Quick reaction hormones - work fast when body signals an urgent need o Ex. in sulin Slow reaction hormones - afford longer, gradual, and sometimes permanent changes to body Water soluble hormone - bind to protein on surface of target cell and will have signal transduction cascade to nucleus o ex. epinephrine, adrenaline Lipid soluble hormones- moves right thru membrane of target cell and can go straight to nucleus o ex. testosterone Major endocrine glands Adrenal cortex o Monitors blood sugar level o Assists in lipid and protein metabolism Adrenal medulla o Controls cardiac function o Raises blood sugar o Controls size of blood vessels Thyroid gland o Helps regulate metabolism o Growth + development Parathyroid - regulates calcium levels in blood Pancreas islets o Raises and lowers blood sugar o Active in carb metabolism Thymus gland - involved in immune responses
Pineal gland - epithalamus o Influences daily biorhythms- circadian rhythm o Sexual activity Pituitary gland o Involved in growth + development HORMONES OF HYPOTHALAMUS AND PITUITARY Hypothalamus - link b/ w nervous sys and endocrine sys Located in brain superior to pituitary and inferior to thalamus Communicates w pituitary by secreting RH (releasing hormones) and IH (inhibiting hormones) Hormones of the hypothalamus Stimulate anterior pituitary to ……. Gonadotropin RH - release luteinizing hormone + follicle stimulating hormone o Men- cause testicles to make testosterone o Women- cause ovaries to make estrogen and progesterone Growth hormone RH - release growth hormone Growth hormone IH (somatostatin )- inhibit release of growth hormone Thyrotropin RH - release thyrotropin o Control thyroid gland growth o Function to control metabolic rate, heat generation, neuromuscular, heart rate Prolactin RH - release prolactin o Milk production in females o Metabolism, immune sys, dev of pancreas Prolactin IH (dopamine)- inhibits release of prolactin Corticotropin RH - release adrenocorticotropic hormone (ACTH) o Involved in stress, depression, addiction response Other organs….. Oxytocin o Targets uterus to stimulate contractions o Targets mammary glands to secrete milk Antidiuretic hormone (vasopressin )- targets kidney and blood vessels to increase water retention Pituitary (master gland)- many hormones it secretes act on other endocrine glands Located in sella turcica of sphenoid bone under hypothalamus Infundibulum- connects pituitary to hypothalamus Hormones from Anterior Pituitary gland
Thyroid stimulating hormone (thyrotropin )-

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