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24 Cards in this Set
- Front
- Back
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Define endocrinology.
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Cellular communication by means of hormones.
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Define hormone.
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Chemical messenger released by endocrine (ductless) gland; transported in low concentrations to target cells
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Define neurohormone.
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Chemical messenger secreted by neurons transported via circulation to target cells.
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What roles do receptors play in endocrinology? Where are they expressed?
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Receptors define target cells and specific action of hormones
Expressed on cell surface (for hormones that cannot pass cell membrane) or in cytoplasm/nucleus (for hormones that can cross cell membrane; may act as transcription factors) |
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Contrast the following terms:
Autocrine Endocrine Paracrine |
Autocrine: When a hormone is released into circulation and acts back on the releasing cell
Endocrine: Distal action; hormone released by cell into circulation (most common pathway) Paracrine: local action; cell releases hormone to act on neighboring cell (least common pathway) |
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Contrast negative feedback with positive feedback.
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Negative feedback: most common control of hormone secretion; hormone directly or indirectly inhibits further secretion
Positive feedback: uncommon mechanism of hormone secretion control; usually indirectly stimulates further secretion |
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Starting with the hypothalamus and ending with target tissues, describe the feedback loops for Thyroid Releasing Hormone.
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Hypothalamus releases TRH
Pituitary releases TSH Thyroid releases T4 T4 circulates to target tissues and feeds back to the hypothalamus (negative feedback) |
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How is the effect of a hormone mediated if it cannot cross a cell membrane?
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Binds a cell surface receptor and employs second messenger signaling
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What are the benefits of having a protein-bound hormone?
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Provides reservoir and extends half-life for hormone action
(Proteins are transporters) |
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Are bound-proteins able to bind receptors or function in feedback regulation?
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No, only free proteins can bind receptors or provide feedback
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What's an example of a non-specific hormone binding protein?
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Albumin
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What do Free and Total concentrations refer to?
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Free = concentration of unbound hormone
Total = concentration fo unbound and bound hormone |
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Describe the signaling required for release of growth hormone.
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What's an example of a non-specific hormone binding protein?
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Albumin
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What do Free and Total concentrations refer to?
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Free = concentration of unbound hormone
Total = concentration fo unbound and bound hormone |
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Describe the signaling required for release of growth hormone.
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Describe the signaling required for release of growth hormone.
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Describe the signaling required for release of LH and FSH.
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Describe the signaling required for release of corticotropin.
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Describe the signaling required for release of thyrotropin (TSH).
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How does food effect insulin release?
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Food high in sugar stimulates insulin release
Lack of food inhibits insulin release |
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Describe the endocrine controls of calcium levels in the body.
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What is the difference between a primary and secondary endocrine deficiency?
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Primary: dysfunction originating in the peripheral endocrine gland itself
Secondary: understimulation or overstimulation by the pituitary |
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How might endocrine resistance disorders arise?
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Problems in receptors or second messengers
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