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| convergence |
-input from mult sources
-summed input |
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mcs5109 Mon, 22 Sep 2008 00:06:51 GMT |
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| neurotransmitter termination |
-diffuse away from synapse
-inactivated by enzymes in the synatic cleft
-transport into presynaptic cell or glial cells |
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mcs5109 Sun, 21 Sep 2008 23:58:38 GMT |
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| opinoid peptides |
-enkephalins and endorphins (promotes sense of well-being)
-mediate analgesia
-pain relief |
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mcs5109 Sun, 21 Sep 2008 23:42:42 GMT |
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| Substance P |
-involved in pain pathways |
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mcs5109 Sun, 21 Sep 2008 23:42:42 GMT |
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| PNS neurotransmitters |
-ACh, NE, E |
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mcs5109 Sun, 21 Sep 2008 20:01:48 GMT |
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| CNS neurotransmitters |
-acetylecholine, amines, aas, purines, gases, peptides, lipids |
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mcs5109 Sun, 21 Sep 2008 20:01:48 GMT |
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| postsynaptic cells |
-can be neuron or non-neuron |
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mcs5109 Sun, 21 Sep 2008 19:41:02 GMT |
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| too much/little K+ |
-shift resting membrane potential up
-respond to smaller ESPSs
if too low, won't respond to ESPSs as usual and muscle weakness occurs--> Gatorade! |
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mcs5109 Sun, 21 Sep 2008 19:41:02 GMT |
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| MS |
-demyelinating disease
-fatigue, muscle weakness, loss of vision
-autoimmune disorder?
-depolarizations must be stronger to work |
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mcs5109 Sun, 21 Sep 2008 19:34:59 GMT |
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| speed of APs |
-diameter of axon and reistance of axon membrane to ion leakage
-larger diameter, less resistance
-myelin sheath prevents ions from flowing out; limits contact w/ ECF
Nodes:
-each nodes has lots of Na+ voltage-gated channels
-keep AP up as goes throgh axon
-saltatory conduction lets APs jump from node to node |
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mcs5109 Sun, 21 Sep 2008 19:34:59 GMT |
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| reasons potentials lose stength |
-current leak: + charges move out
-cytoplasmic resistance: cytoplasm resists flow of electricity
-must reach trigger zone at threshold voltage so Na+ voltage-gated channels open and AP occurs
-or, just died out along axon |
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mcs5109 Sun, 21 Sep 2008 19:34:59 GMT |
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| graded potentials |
-open chemically gated ion channels
-allows ions to enter/leave
-or, mechanical stimuli
-ex: K+ channels can close and depolarize the cell EPSP
-stength of initial depolarization depends on how much charge enters teh cell (if more Na+ channels open)
-diminish in stength |
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mcs5109 Sun, 21 Sep 2008 19:34:59 GMT |
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| autonomic motor division |
- aka visceral nervous system b/c it controls various internal organs
-divided into sympathetic and parasympathetic |
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mcs5109 Sun, 21 Sep 2008 19:13:13 GMT |
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| efferent neurons |
-somatic motor division (controls skeletal muscles)
-autonomic motor division aka visceral (controls smooth and cardiac muscles, exocrine glands, some endocrine glands, adipose tissues)
-PNS |
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mcs5109 Mon, 22 Sep 2008 00:46:42 GMT |
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| PNS |
-afferent and efferent |
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mcs5109 Sun, 21 Sep 2008 19:13:13 GMT |
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| CNS |
brain and SC
-integrate info of afferent PNS and determines if a response needed |
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mcs5109 Sun, 21 Sep 2008 19:13:12 GMT |
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| long term depression |
-NO implicated
-may be opposite of LTP |
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mcs5109 Sun, 21 Sep 2008 18:38:27 GMT |
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| LTP |
-hippocampus: memory pathways
-glutamate stimulates (increases Ca into neurons to stimulate)
-heavilty used neurons experience long term increase in effectiveness of operation
-increased Ca uptake increase nuerotransmitter output
-2nd messengers involved
-activity at synapse induces sustained changes in quality/quantity of synaptic connections
-glutamate important
-NMDA channel
-Ca+2 goes into cell
-releases a paracrine that acts on presynaptic cell to release more neurotransmitter
-postsynaptic cell also becomes more sensitive to glutamate (inserting more glutamate receptors in post synaptic membrane?) |
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mcs5109 Mon, 22 Sep 2008 00:35:32 GMT |
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| gases |
-NO in learning/memory
-neuronal damage during stroke
-diffuses freely
-binds to proteins
-2-30 sec half life |
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mcs5109 Sun, 21 Sep 2008 23:43:58 GMT |
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| neuropeptides |
-endogenous opinoids: endorphins, enkephalons (analgesic actions reduce pain)
Substance P: afferent( sensory) neurons; pain, nervous immune system link (arthritis) |
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mcs5109 Sun, 21 Sep 2008 18:38:27 GMT |
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| amino acids are neurotransmitters |
-glutamate, aspartate--> excitatory in CNS; important in memory/learning
-glycine, GABA--> inhibitory in CNS; Cl- channels open to hyperpolarize; valium enhances action; anesthetic action |
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mcs5109 Sun, 21 Sep 2008 23:40:07 GMT |
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| MAO |
-breaks down Serotonin, NE, and E |
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mcs5109 Sun, 21 Sep 2008 18:38:27 GMT |
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| serotonin |
-derived from tryptophan
-catabolized by MAO
-excitatory for muscle
-inhibitory for sensation
-activity low during sleep, high during activity
-LSD stimulates action, 5-HT receptors
-psilocybin analog
-prozac inhibits reuptake of serotonin
-aka 5-HT |
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mcs5109 Sun, 21 Sep 2008 23:35:25 GMT |
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| parkinson's disease |
-substantia nigra where dopamine produced
-lack of dopamine
-shakes, can't initiate mvt
-L dopa therapy |
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mcs5109 Sun, 21 Sep 2008 18:26:14 GMT |
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| dopamine |
-CNS
-pleasure pthways
-motor pathways
-analogs: metamphetamine, peyote,
-cocaine inhibits uptake of dopamine
-parkinson's disease |
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mcs5109 Sun, 21 Sep 2008 18:26:14 GMT |
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| ANS parasympathetic pathways |
-distribution via cranial nerves and pelvic nerve from sacral region of SC
-crancial nerves II, VII, IX, X< have 90% of body's parasympathetic fibers
preganglionic fibers: ACh
postganglionic fibers: ACh (cholinergic muscarinic receptors on target tissue |
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mcs5109 Sun, 21 Sep 2008 18:26:14 GMT |
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| ANS sympathetic pathways |
-thoraiclumbar region of spine
-use sympathetic chain ganglia via ventral root to blood vessles, sweat glands, hair
-collateral ganglia to viscera (heart, GI, kidney)
-runs parallel to spinal cord
preganglionic fibers: ACh
postganglionic fibers: NE (adrenergic receptors (a or b) on target tissue |
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mcs5109 Sun, 21 Sep 2008 18:26:14 GMT |
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| somatic nervous sytem |
-ACh
-nicotinic receptors |
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mcs5109 Sun, 21 Sep 2008 18:12:13 GMT |
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| beta receptors for NE, E |
-greater affinity for E
b1: stimulates heart rate, contractility, kidney and fat lyposis
b2: inhibits (relaxes smooth muscle) esp. in lung, heart, skeletal muscle, blood vessels |
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mcs5109 Sun, 21 Sep 2008 18:12:13 GMT |
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| alpha receptors for NE, E |
-greater affinity for NE
a1: stimulates constriction of smooth muscles, esp. in vessels
a2: same and inhibition of preganglionic neurons (neurotransmitter inhibition) |
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mcs5109 Sun, 21 Sep 2008 23:52:45 GMT |
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| E, NE general action |
-sympathetic stimulation
-cardiac rate stimulator, increase BP, inhibit GI tract
-E, NE have different actions depending on receptor type |
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mcs5109 Sun, 21 Sep 2008 18:12:13 GMT |
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| adrenergic fibers |
-nerve tracts using E, NE |
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mcs5109 Sun, 21 Sep 2008 18:06:59 GMT |
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| NE deactivation |
-Monamine oxidase (MAO)
-from mitochrondria in nerve endings
-many antidrpessants are MAO inhibitors
Catechol-O-methyltransferase (COMT)
-peripheral tissues (liver, kidney, etc.)
-actively transported back to presynaptic terminal
-either repackaged into vesicles or broken down by MAO |
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mcs5109 Mon, 22 Sep 2008 00:01:12 GMT |
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| amine synthesis |
-from dietary tyrosine
-tyrosine hydroxylase makes Dopa
-Dopa decarboxylase makes dopamine
-dopeamine B-hydroxylase makes NE
-N-methyltransferase makes E (mostly a hormone) |
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mcs5109 Sun, 21 Sep 2008 18:06:59 GMT |
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| biogenic amine neurotransmitters |
-catecholamines (NE, E, dopeamine)
-serotonin
-histimine
-derived from single aas
-all active in CNS |
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mcs5109 Sun, 21 Sep 2008 23:36:10 GMT |
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| zyban |
-general antidepressant
-dopamine reuptake inhibitor |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| chantix |
-ACh antagonist/agonist
-suicide noted |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| nicotrol |
-nicotine replacement therapy for ACh receptor activation |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| alzheimers |
-ACh synthesis down |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| myasthenia gravis |
-few ACh receptors due to autoimmune degradation |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| botox |
-prevents ACh release |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| sarin |
VX nerve gas
-AChE inhibitor
-asphyxiation
-prevents mvt of diaphragm
-2 part autoinjector:
-atropine: blocks ACh stimulation
-pralidoxime: regenerates bound AChE |
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mcs5109 Sun, 21 Sep 2008 18:00:50 GMT |
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| acetylecholinesterase |
degrades ACh
choline transported back to axon terminal
-in ECF
-and in membrane of postsynaptic cell
-choline actively transported back to presynaptic cell |
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mcs5109 Mon, 22 Sep 2008 00:00:02 GMT |
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| nicotinic |
-neuron and skeletal muscles
-nicotine stimulates
-blocked by curare, muscles relaxation
-skeletal muscle-type receptors (bungarotoxin binds, blocks irreversibly, causing paralysis)
-neuron type receptors
-nicotine is an agonist
-found on skeletal muscles of automatic division of PNS and in CNS |
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mcs5109 Sun, 21 Sep 2008 23:48:14 GMT |
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| Muscarinic |
-smooth, cardiac muscles, glands
-blocked by atropine (dilation of pupils)
-CNS and autonomic parasympathetic division of PNS |
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mcs5109 Sun, 21 Sep 2008 23:49:50 GMT |
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| acetylcholine |
-parasympathetic stimulation
-(cardiac rate inhibitor, lower BP, GI stimulation)
-neurotransmitter for neuromuscular junction (voluntary action for skeletal muscles)
-2 post synaptic cholinergic receptors: muscarinic and nicotinic |
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mcs5109 Sun, 21 Sep 2008 20:06:51 GMT |
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| acetylecholine synthesis |
-choline plus acetyl CoA
-mediated by coline acetyltranferase
-choline small molecule that's recycled
-takes place in axon terminal
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mcs5109 Sun, 21 Sep 2008 20:08:32 GMT |
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| presynaptic inhibition |
-inhibition of Ca+2 channel openings, reduces amount of neurotransmitter released
-decreases neurotransmitter released
-changes synthesis of enzymes, membrane transporters, receptors |
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mcs5109 Mon, 22 Sep 2008 00:15:32 GMT |
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| presynaptic facilitation |
-stimulation of Ca+2 channel openings, more neurotransmitter released
-increases neurotransmitter released |
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mcs5109 Mon, 22 Sep 2008 00:08:27 GMT |
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| temporal summation |
-2 impulses in rapid succession |
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mcs5109 Sun, 21 Sep 2008 17:42:56 GMT |
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| spatial summation |
2 impulses at same time |
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mcs5109 Sun, 21 Sep 2008 17:42:56 GMT |
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| IPSP |
Fast: increase in Cl- conductance
Slow: increase in K+ conductance |
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mcs5109 Sun, 21 Sep 2008 17:35:15 GMT |
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| EPSP |
-activating neurotransmitter mediated channels
-moves cell closer to threshold
-easier to depolarize
-hypopolarizes cell
Fast: increase in Na+ conductance
Slow: decrease in K+ conductance |
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mcs5109 Sun, 21 Sep 2008 17:35:15 GMT |
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| synaptic delay |
-time neurotransmitter takes to cross synapse |
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mcs5109 Sun, 21 Sep 2008 17:30:19 GMT |
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| antidromic |
axon to cell body 0.1% |
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mcs5109 Sun, 21 Sep 2008 17:30:19 GMT |
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| orthodromic |
cell body to axon 99.9% |
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mcs5109 Sun, 21 Sep 2008 17:30:19 GMT |
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| axon terminal |
aka bouton aka presynaptic terminal |
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mcs5109 Sun, 21 Sep 2008 17:30:18 GMT |
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| chemical synapses |
-30-50nm
-begins w/ AP
-accounts for most delays in signal transduction
-0.5msec
-vast majority
-initiates electrical response or 2nd messenger
-neurotransmitter synthesis takes place in nerve cell body or axon terminal (terminal doesn't have organelles for protein synthesis)
-vesicles "docked" at active zones along membrane closest to cleft |
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mcs5109 Sun, 21 Sep 2008 19:45:43 GMT |
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| electrical synapse |
-2-3nm
-gap junction
-electrical current
-crosses w/o chemicals
-pass electrical current directly from one cell to cytoplasm of other via gap junctions
-info flows in both directions
-mainly in neurons of CNS
-rapid conduction
-also, chemical signal molecules diffuse b/w adjacent cells |
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mcs5109 Sun, 21 Sep 2008 19:42:39 GMT |
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