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20 Cards in this Set
- Front
- Back
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Ligand
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Ligand: a chemical messenger
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Source
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Source: cells which produce the ligand
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Target
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Target: has receptors for and responds to messenger
Source -> Ligand -> Target |
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Paracrine chemical messenger
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Chemical that serves to signal a nearby cell
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Autocrine
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Chemical that signals the same cell that secreted it
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Neurotransmitter
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Messenger produced by neurons
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Hormone
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-Messenger produced by endocrine cells
-Secreted into blood via interstitial fluid |
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Neurohormone (2)
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- Messenger produced by neurons
- Secreted into blood via interstitial fluid - Examples: Antidiuretic hormone (ADH), oxytocin |
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Amino acids (3)
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-Lipophobic
-Target cell receptors on cell membrane -Only four amino acids function as messengers, all as neurotransmitters -Examples: Glutamate, aspartate, glycine, GABA |
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Examples of amine messengers (2)
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-Catecholamines
=Derived from tyrosine +Dopamine +Norepinephrine (noradrenalin) +Epinephrine (adrenalin) -Serotonin =Made from trytophan |
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Peptide/Protein Messengers (4)
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-Most abundant type of ligand
-Lipophobic -Target receptors on cell membrane -Made of chains of amino acids |
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Steroid ligands (4)
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-Lipophilic
-Intracellular target receptors -Derived from cholesterol -All steroid ligands function as hormones |
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How ligands get around
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Blood borne transport
Hydrophillic messenger Hydrophobic messenger |
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Messenger half-life
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-Time for a chemical to decrease concentration in half
-Concentration of messenger could be in blood or interstitial fluid |
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-Messengers dissolved in plasma
-Messengers bound to plasma protein |
-Messengers dissolved in plasma
-Have relative short half-life -Example: Half-life insulin is <10 min -Messengers bound to plasma protein -Have relative long half-life -Example: Half-life of cortisol = 90 min |
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Agonist (2)
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-Chemical which binds to receptor
-Action mimics normal response |
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Antagonist (3)
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-Chemical which binds to receptor
-Binding does not result in response -Competes with normal ligand |
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Beta-endorphin = endogenous opiate
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Beta-endorphin binds to mu opiate receptors producing analgesia
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Morphine = mu receptor agonist
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Administration of morphine produces analgesia
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Naloxone = mu receptor antagonist
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Administration of naloxone blocks morphine or beta-endorphin produced analgesia
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