Term
| Endocrine glands/endocrine cells |
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Definition
- pituitary gland, pineal gland, thyroid gland, parathyroid glands, adrenal gland (cortex and medulla)
- pancreas, thymus, gonads, hypothalamus
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Term
| Mechanisms of hormone release |
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Definition
- Humoral: response to changing of ions or nutrients
- Neural: stimulation by nerves
- Hormonal: stimulation from other hormones
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Term
| Endocrine System General Characteristics |
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Definition
- system of ductless glands that secrete hormones
- hormones are messenger molecules
- circulate in blood (exceptions paracrine, autocrine)
- act on target cells (exceptions paracrine, autocrine)
- target cells respond to hormones for which they have receptors
- the effects are dependant on the programmed response of the target cells
- hormones are just molecular triggers
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Term
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Definition
- are helpful because can easily pass through the membrane
- steriods (synthesized from cholesterol)-released by reproductive organs
- thyroid hormones
- nitric oxides (gas)-both hormone and neurotransmitter
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Term
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Definition
- Amines (released by adrenal medulla, thyroid, pineal gland)
- peptide hormones (largest class hormones secreted by hypothalamus, pituitary gland, heart, thymus, digestive tract, pancreas)
- eicosanoids-open 5 C ring-derived from 20 fatty acid- prostaglandins and leukotriene’s, important paracrine factors
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Term
| Mechanisms of hormone action |
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Definition
- for hormone to affect target cell, it must first interact with appropriate receptor
- hormone receptors may be on cell membrane or inside cell
- water sol hormones-cannot penetrate cell membrane: receptors found on cell membranes
- lipid sol hormones pass into cell and bind to receptor in cell nucleus
- binding of hormones to receptors may lead to release of many 2nd messengers (called amplification)
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Term
| Mechanism of water sol hormone action |
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Definition
- hormone (1st messanger) released from endocrine gland->bloodstream
- travels through body, passes out of capillary and binds to appropriate receptor
- receptor binding induces apperance/action of a 2nd messenger which includes enzyme activators, inhibitors, or cofactors
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Term
| Most important second messengers |
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Definition
- cyclic AMP, cyclic GMP, and calcium ions
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Term
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Definition
- common link between between 1st and 2nd messengers
- an integral membrane protein that interacts with the membrane receptor
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Term
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Definition
- binding of hormones to receptors may lead to release of thousands of 2nd messengers
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