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p. 214, Silverthorn2001. 2nd ed. Human Physiology. Prentice Hall
synapse
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3
Good morning,This is a reminder that Dr. Herman Gordan (UA Associate Professor, Cell Biologyand Anatomy) will speak at Doings this Friday Sept 9th at 4pm (Gould-Simpson 601).The title of his presentation is:
"Self-organization of transmembrane kinases in synaptogenesis"
E. Fiona Bailey Ph.D., Research Assistant Professor, Department of Physiology,College of Medicine, The University of Arizona. Tucson AZ, USA.Phone: (520)626-8299. Fax: (520)621-8170
Both function via reflex arcs, but often opposite effectsEfferent signal with two neurons:1. Preganglionic (NT released is Acetylcholine [Ach])
2. Postganglionic (PNS, receptor is nicotinic ACh)
Difference between Symp. and Para. is in:1. Location of postganglionic somata2. Postganglionic NT 3. Receptors on target tissues
-Muscle reflexes in spinal cord, autonomic to brain
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Autonomic NS
1-Postganglionicsomata nearer CNSin chain ganglia
Sympathetic Parasympathetic1-Postganglionic
somata near effector,or in effector organ
2-Postganglionic NTis Norepinephrine
2- Postganglionic NTis ACh
3-Effector receptoris alpha or betaadrenergic
3-Effector receptor ismuscarinic ACh
Difference between Symp. and Para. is in:1. Location of postganglionic somata2. Postganglionic NT 3. Receptors on target tissues
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31Hill et al. 2004, Fig 10.12
32Hill et al. 2004, Fig 10.13
Norepinephrine
Acetylcholine
Know a couple of examples:
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33Hill et al. 2004, Fig 10.13
Know a couple
of examples:
Norepinephrine
Acetylcholine
34Hill et al. 2004
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Biological Clocks later if we have time(Hill et al. pages 274-280)
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“Squid axons are important to physiologists, and to the squid.”Hill et al. 2004, p.281
Sir Alan Hodgkin, Nobel Prize 1963
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Neurons:
Hill et al. 2004, Fig 11.1
38Hill et al. 2004, Fig 11.2
1.PNS
2.CNS
3.Metabolic support
4.Phagocytes/immune
4 types of Glial Cells
Outnumber neurons 10:1 in mammalian brain
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Osmotic Properties of Cells and Relative Ion Concentrations
Na+Na+ K+K+
Cl-Cl-
4-12 Randall et al. 2002
Ca+
Ca+
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Movement Across Membranes
Electrochemical Gradient
Concentration gradient
Electrical gradient
Electrochemical equilibrium
Equilibrium potential (Ex in mV)
Na+Na+
--
--
-
-
-
-
-
-
-
++
+
+
+
+
+
+
++
++
K+K+
--
--
-
-
-
-
-
-
-
++
+
+
+
+
+
+
++
++
when [X] gradient = electrical gradient
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Equilibrium potential (Ex in mV)
“Every ion’s goal in life is to make the membrane potential equal its own equilibrium potential (Ex in mV)”
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To change Vm, A Small Number of Ions Actually MoveRelative to the Number Present both
Inside and Outside the cell
The concentration gradients are not abolishedWhen the channels for an ion species open
Gradients allow for ‘work’ to be done, e.g., action potential sends signal along axon
-Gradient established by pumps (ATP)
Membrane Potential
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Membrane Potential
- Driven by ions that are permeable to the membrane (and have different [ ]in as compared to [ ]out a.k.a. gradient created with ATP)
- emf determines which direction a given ion (X) will move when the membrane potential is known
- Equilibrium Potential (Ex in mV):~The equilibrium potentials of all the permeableions (a function of their established gradients) will determine the membrane potential of a cell
emfx = Vm - Ex
- K+ for example
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Membrane Potential
- Resting Membrane Potential driven by K+ efflux and,to a lesser extent, Na+ influx
- Na+/K+ ATPase pump generates gradients that, for these permeable ions, determinemembrane potential