Exam 2 Flashcards
(244 cards)
Parts of the Neuron
Cell Body & Nucleus Dendrites Axons Terminal Buttons or Axon Endings Glia Cell- “Schwann cells”
Cell Body & Nucleus
As in all cells, these help keep the cell alive & enable it to reproduce.
Dendrites
Receive messages from adjacent neurons.
Axons
Transmit messages through the neuron.
Terminal Buttons or Axon Endings
Send messages to adjacent neurons.
Glia Cell- “Schwann cells”
Wraps around axons, forming myelin sheath
Saltitory Conduction and Nodes of Ranvier
Enables transmission to skip from node to node through the neuron
Multiple Sclerosis
A disorder where the myelin deteriorates, broken down by the immune system for an unknown reason.
Ions
Are simply “charged particles”.
Salt (NaCl) + H2O= H2O + (Na+) + (Cl-)
The Cell Membrane
A phospholipid bilayer with proteins embedded. Hydrophobic heads (water soluble layer), hydrophilic tails (fat soluble layer)
Transmission Within A Neuron: Resting Potential
Inside of the neuron is slightly negative with respect to the outside.
About -70 millivolts
Transmission Within A Neuron: Graded Potentials
Stimulation produced change in the resting potential.
Graded means the change mirrors the amount of stimulation.
Two kinds: Hyperpolarization, Depolarization
Hyperpolarization
increased polarity
Depolarization
decreased polarity
Transmission Within A Neuron: Threshold
- Refers to the voltage level that needs to be reached for an action potential to occur.
- Threshold is about -60 to -65 millivolts.
Transmission Within A Neuron: Action Potential
- A large enough depolarization causes the inside of the cell to become positive with respect to the outside at the point of stimulation.
- Is contagious & results in the info being carried down the length of the cell.
- Is all-or-none, it either happens or it doesn’t happen.
Synaptic Transmission - Steps
Must be an action potential in presynaptic neuron.
Molecules involved in transmitter synthesis must be transported into cell.
Transmitter must be synthesized.
Transmitter must be stored (in vesicles).
Transmitter must be released into synapse.
Transmitter must interact with receptors in membrane of postsynaptic neuron.
Transmitter must be deactivated (by reuptake or breakdown by MAO).
EPSP, Excitatory Postsynaptic Potential
lead to depolarizations, more likely to see an action potential
IPSP, Inhibitory Postsynaptic Potential
lead to hyperpolarizations, less likely to see an action potential
Excitatory synapse
Round synaptic vesicles, postsynaptic thickening
Inhibitory synapse
Oval synaptic vesicles, no postsynaptic thickening
Spine synapse
Synapse has a “spine”, round synaptic vesicles, postsynaptic thickening
Spatial Summation
Two small EPSP’s that occur in close proximity add together to create an action potential.
Temporal Summation
When two EPSP’s occur in rapid succession from the same terminal button, the postsynaptic neuron doesn’t have time to recover completely from the first stimulation and an action potential results.