Chapter 9 Review

Chapter 9 Review - Chapter 9 Review Before Chapter 9:...

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Chapter 9 Review Before Chapter 9: ACETYLCHOLINE (ACh) AS A NEUROTRANSMITTER -ACh binding to its receptor causes the opening of chemically regulated gates - causes a depolarization, EPSP -causes a hyperpolarization IPSP -excitatory NT -neurons in CNS, somatic motor neurons at neuromuscular junction - excitatory or inhibitory -different responses, different subtypes of Ach receptors - nicotinic ACh receptors - stimulatory effect on skeletal muscle cells, activated by nicotine -specific regions of the brain, autonomic ganglia, skeletal muscle fibers -release of ACh causes muscle contraction - muscarinic ACh receptors - effect on other cells, activated by muscarine -plasma membrane of smooth muscle cells, cardiac muscle cells, cells of particular glands -release of ACh activate muscarinic receptors, required for regulation of cardiovascular system, digestive system - agonist : drugs that active receptor proteins -muscarine of muscarinic ACh receptors -nicotine of nicotinic receptors - antagonists : drugs that inhibit receptor proteins -atropine of muscarinic receptors -curare, etc. of nicotinic receptors Chemically Regulated Channels Ligand-Gated Channels -NT is the ligand that binds to its specific receptor protein -“ligand-gated” ion channels: receptor protein is also ion channel -two functions of same protein -extracellular site that bind to NT ligand -spans the plasma membrane with central ion channel -EPSP vs. AP -AP in axons (voltage-gated channels), EPSP in dendrites and cell body -EPSPs have no threshold (ACh released from single synaptic vesicle produces tiny depolarization) - EPSPs -no threshold -graded in magnitude (not all or nothing) -no refractory period -summation (depolarizations of several EPSPs can be added together) G-Protein-Coupled Channels -receptors and ion channels are different, separate membrane proteins -binding of NT ligand to receptor can open the ion channel only indirectly
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- G-proteins subunits : alpha, beta, gamma -binding of ACh, alpha subunit dissociates, beta-gamma complex forms -depends which one diffuses through the membrane until it binds to an ion channel NOREPINEPHRINE AS A NEUROTRANSMITTER - Norepinephrine : used as a NT in PNS and CNS (like ACh) -sympathetic neurons of PNS use norepinephrine as NT -at synapse with smooth, cardiac muscles, and glands -neurons in the CNS, behavioral arousal MIDBRAIN - Midbrain (mesencephalon) : between diencephalon and pons - corpora quadrigemina : four rounded elevations on the dorsal surface of the midbrain - superior colliculi : two upper mounds, visual reflexes - inferior colliculi : immediately below, auditory information - cerebral peduncles : pair of structures, ascending and descending fiber tracts - red nucleus : area of gray matter deep in midbrain, maintains connections with cerebrum and cerebellum, motor coordination - substantia nigra : nigrostriatal system (dopaminergic neurons) projects form it to corpus striatum of basal nuclei, motor coordination, produce Parkinson’s disease - ventral tegmental area (VTA)
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This note was uploaded on 10/04/2011 for the course VPHY 3100 taught by Professor W during the Fall '05 term at UGA.

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Chapter 9 Review - Chapter 9 Review Before Chapter 9:...

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