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26 Cards in this Set
- Front
- Back
Targets
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effectors
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def: Endocrine System
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the network of glands and tissues that secrete hormones
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def: hormones
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chemical messengers produced in one tissue, carried by the blood to act on other parts of the body
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def: exocrine secretion
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secretions that do not contain hormones and are released through ducts into a body compartment. ex: digestive enzymes secreted by the pancreas
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How do hormones first affect a cell?
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They bind to a protein receptor on the target cell
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characteristics of Peptide hormones
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-large
-hydrophilic -charged -can't diffuse across plasma membrane |
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def: kinase
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an enzyme that catalyzes the transfer of a phosphate group from a donor such as ATP or ADP.
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def: phosphorylate
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To add a phosphate group to an organic molecule
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What are some of the peptide hormones effects?
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It turns on a protein kinase that phosphorylates certain proteins and changes their activity, or releases secondary messengers in the cell such as calcium or cyclic AMP that amplify the signal and alter many different cellular activities
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def: signal transduction cascade
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The form of indirect signaling shown in peptide hormones
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How are peptide hormones made?
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They're synthesized on the rough ER in the cell, then packaged and processed in the Golgi
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What are characteristics of steroid hormones?
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-small
-hydrophobic -most are derived from cholesterol -can dffuse into the cell through the plasma membrane |
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How does the steroid hormone affect a cell?
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It diffuses through the cell membrane and binds to the steroid hormone receptors. THe hormone-bound receptors enter the nucleus and bind to target regions in genes that regulate transcription, turning the genes on or off.
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What are some of the steroid hormone's effects?
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They change gene transcription and protein expression
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How are steroid hormones secreted?
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They freely diffuse through membranes and are not stored after production. The rate of their production is regulated by controlling the activity of the enzymes that produce the hormones.
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def: endocrine gland
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ductless glands
secrete their chemical messengers directly into body fluids |
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neurosecretory cells
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specialized nerve cells that secrete hormones
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prostaglandins (PGs)
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modified fatty acids, often derived from lipids to the plasma membbrane. Prostaglandins in semen stimulate contraction of smooth muscles in the wall of the uterus, helping to convey sperm to egg.
Prostaglandins secreted by cells of the placenta cause chemical changes in nearby muscles of the uterus Hep induce fever and inflammation and intensify the sensation of pain. -anti-inflammatory effects of aspirin and ibuprofen result from the inhibitory effects of the drugs son prostaglandin synthesis. |
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PGE and PGF
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have opposite effects on the smooth muscle cells in the walls of blood vessels serving lungs.
PGE causes muscles to relas-promotes oxygenation of the blood. PGF signals the muscles to contract, constricting the vessels and reducing blood flow throughout the lungs. |
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Signal-transduction pathway
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a series of molecular changes that converts an extracellular chemical signal to a specific intracellular response.
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tropic hormones
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hormones that have other endocrine glands as their targets
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islets of Langerhans
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in pancreas: clusters of endocrine cells that secrete two major hormones directly into the circulatory sytem
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alpha cells
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secretes the peptide hormone glucagon
-in islet of Langerhan |
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beta cells
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secretes the hormone insulin
-in islet of Langerhan |
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Type II diabetes mellitus
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characterized by either a deficiency of insulin or a reduced responsiveness in target cells due to some change in insulin receptors
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catecholamines
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compounds synthesized from the amino acid tyrosine
ex: epinephrine, norepinephrine |