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40 Cards in this Set
- Front
- Back
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Cell to cell commucation(core physiological concept)
Neurons are designed for cell to cell communication What is it needed for? |
needed for homeostatis
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Neurons
What do they do? How do they do it? |
Receive stimulus(form of energy cells can recieve)(wide range) - Sensory input
Form membrane currents (graded and action) - ion movement through membrane(changes sensory input) Information flow - info in and info out synapses - connection to other cells |
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Neuron anatomy
What are the different parts of the Nueron? |
cell body
Dendrites - roots of a tree, (tiny dendritic spines) Axon - can be really long (3 meters) Myelin (butons - look up) Synapse |
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Neurophysiology
What functions do neurons serve? |
information transfer
information modification (integration)(listens to thousands of other cells, then makes a decision and sends out a signal) sensory perception information storage (memory) Muscle control Consciousness Learning Emotions |
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Dendrites
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Entry to system
Branched or single membrane process smaller spines (predicated by protiens) Ligand(chemicals) and voltage-gated channels (recognized by proteins) - chemicals cause membrane to let ions in, voltage(potential energy) changes to open channels to let ions in Information Input - passive and active zone (ions changing...) |
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Cell Body (neurons)
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Prominent nucleus
Golgi, many mitochondria Nissl bodies - rER, extensive amounts of protein.... |
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Axons
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single or branched
Hillock - first piece of axon Voltage-gated channels Extensive transport (retrograde and anterograde - toward and away from cell body) |
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Synapse
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Connection between two cells (50 nm apart) - like a switch giving your body control of what cells it's communicating with
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Electrical process
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development of ion movement across membranes
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check slides
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check slides
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Ion gradients
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changes form of energy(cannot make or destroy energy)
Na is pumped out of cell, K is inside for the most part, causing a potential energy |
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Membrane potential
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Differences in ion districution (required energy to happen)
Reprecents potential energy (opportunity to do work more negative charge inside than outside (due to different ion gradients) |
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resting potential Vm
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measured by recording and reference electrodes
-60 cont..... |
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Ohm's Law
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V=IR (V= voltage; R= resistance, I=current)
R=1/G(G=conductance) V=I/G |
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hyperpolarized
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more negative cell interior
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depolarized
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more positive cell interior
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Membrane Channels
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Ions move through channels (ion selective channels)
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Ligand-gated
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opened from the outside by chemicals
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Voltage-gated
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opened from the inside by voltage changes
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leak channels
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left slightly open
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Acetylcholine(ACh) Receptor
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Ligand gated
5 protein subunits (like barrel staves) binding causes a helix to rotate 15 degrees (change in protein)(opens channel for Na) does so by causing protein to change shape (changing function) |
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Electrochemical potential
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Ohm's law regulates movements inside cell
movement of ions down concentration gradient repulsion of like charges causes electrochemical equilibrium |
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Nernst equation
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tells electrochemical equilibrium
(the mV is the charge it reaches in the cell when the ion stops flowing) |
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Equilibrium potential
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membrane potential when chemical and electrical forces are balanced
direction depends on Vm and equilibrium potential |
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Reversal Potential
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equal to equilibrium potential for individual ions
refers to direction of ion flow (ion channels are two-way doors) |
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Local potentials
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Socal stimulus (small part of the membrane)
Localized permeability change ... |
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Graded potential
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ligand-grated channels
inward positive current flow proportional to amount of ligand |
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Action Potential
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Movement of ...
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Refractory period
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cannot start a new action potential
voltage-gated Na.... |
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Action potential propagation
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spread of positive charge(effected by diamerger of axons)
Dependent on length constant affected by myeline |
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Myelinated neurons
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associated cells surround axon with lipid bilayer
Gaps, where action potential occurs. speed is important, fast is good Node of Ranvier needs to have good spacing |
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Synaps (cont)
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contact between nerve and target cell
200-300 angstrom gap pre and post synaptic membrane(target cell) chemical and electrical |
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chemical synapse
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asymmetrical, different sides
Vesicles in presynaptic membrane (neurotransmitter) carry info from one to another cells Ca mediated exocytosis Quantal release |
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Calcium channel(calcium acts like glue on membrain)
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Ca channels
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Neurotransmitters
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many different stuctures
low amounts produced and destroyed in synapse'inhibitory or excitatory... |
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Electrical synapse(for speed)
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direct contact
Current flow in both directions Fast Low percentrage |
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Post synaptic cells
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EPSP - more posiitive
IPSP - more negative ligand gated graded potentials Post and presynaptic inhibition |
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Pre-synaptic inhibition
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forcing cell to be quiet
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Summation Temporal
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multiple ESPSs w/o significant delay at dendrite
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Spacial Summation
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simultaneous EPSPs at multiple dendrietes
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