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42 Cards in this Set
- Front
- Back
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endocrine system
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body system that includes internal organs that secrete hormones
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hormones
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chemical messengers which are released into the blood or lymph to be transported throughout the body
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Endocrine Glands
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ductless glands that empty their hormonal products directly into the blood
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neuroendocrine organ
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hypothalamus since it is both an endocrine organ and has neural functions
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endocrinology
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scientific study of hormones and the endocrine organs
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autocrines
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chemicals that exert the effects on the same cells that secrete them
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paracrines
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act locally; effect other cells
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amino acid based
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most hormones; vary greatly in size
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steroids
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hormones synthesized from cholesterol; only gonadal and adrenocortical
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eicosanoids
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leukotirnes and prostglandin; released by all cell membranes; made of lipids
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target cells
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the cells that are targeted by a certain hormone, must have the correct protien in their cell membrane
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a hormonal stimulus typically produces 1 or more of the following changes in a cell
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1. alters plasma membrane permeability or membrane potential or both, by opening or closing ion channels.
2. stimulates the synthesis of protiens or regulatory molecules such as enzymes inside the cell. 3. activates or deactivates enzymes. 4. induces secretory activity. 5. stimulates mitosis |
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second messengers
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intracellular molecule generated by the binding of a chemical to a plasma membrane receptor, mediates intracellular responses to the chemical messenger
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cyclic AMP
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intracellular second messenger that mediates the effects of the first extracellular messenger (hormone or neuroxmitter); formed from ATP by by a plasma membrane enzyme
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first messenger
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the hormone as it gets to the cell in the second messenger system
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G protein
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protein that relays signals between extracellular first messengers and intracellular second messengers via an effector enzyme
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adenylate cyclase
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effector enzyme generates cyclic AMP from ATP
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Protein kinases
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enzymes that phosphorylate various proteins; many are other enzymes
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phosphodiesterse
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intracellular enzyme that degrades cyclic AMP
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up-regulation
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target cells form more receptors in response to rising blood levels of the specific homones to which they respond
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down-regulation
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prolonged exposure to high hormone concentrations desensitizes the target cells so that they respond less vigorously
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half-life
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the length of time for a hormone's blood level to be decreased by half
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permissiveness
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when one hormone cannot exert its full effects without another homone being present
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synergism
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when more than one hormone produces the same effects at the target cell and their combined effects are amplified
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antagonism
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when one hormone opposes another homone
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negative feedback system
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most common homeostatic control mechanism. the net effect is that the output of the system shuts off the orginal stimulus or reduces its intensity
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pituitary gland
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hypophysis
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pituitary gland (location)
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inside the brain right behind the eyes
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infundibulum
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the connecting stalk of the pituitary gland to the hypothalamus
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posterior pituitary
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the lobe of the pituitary that is made of pituicytes and nerve fibers and releases neurohormones
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neurohormones
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hormones secreted by neurons
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neurohypophysis
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the infundibulum and the posterior pituitary
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hypothalamic-hypophyseal tract
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nerve bundles that run through the infundibulum and connect the neurohypophysis and the hypothalamus
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tropins
tropic hormones |
hormones that rgulate the secretory action of other enocrine glands; except GH all work cAMP 2nd messenger
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Growth Hormone (GH)
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hormone that stimulates growth in general; produced in anterior pituitary ; also called somatotropin
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somatotrophs
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in the anterior pituitary; produce growth hormone
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insulin-like growth factor IGFs
somatomedins |
family of growth promoting hormones made by liver, sk muslcle, bone; does the heavy lifting for the growth hormone
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growth hormone-releasing hormone
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hormone that stimulates secretion of GH
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growth hormone-inhibiting hormone; somatostatin
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hormone that inhibits the secretion of GH
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gigantism
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caused by hypersecretion of GH in children; results in tall adults and proper proportions
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acromegaly
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enlarged extremities; hypersecretio of GH after the epiphyseal plates have fused; effects hands/feet/face
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pituitary dwarfism
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result of hyposecretion of GH in children, they remain small but proportion
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