Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/21

Click to flip

21 Cards in this Set

  • Front
  • Back
Define Synapses.
def. junction between two neurons, or between a neuron and a muscle or gland that enables one cell to electrically and/or biochemically influence another cell
Define Synaptic Transmission.
primary means of rapid inter-neuronal communication in the brain
Features of Synaptic Transmission
1. presynaptic cell
2. postsynaptic cells
3. postsynaptic targets
Function of a Presynaptic Cell.
initiates the (CHEMICAL) signal (VIA FUSION OF A NT-FILLED VESICLE WITH THE CELL MEMBRANE (EXOCYTOSIS))
Function of a Postsynaptic (target)Cell
receives the signal (THE NT IS RECIEVED BY RECEPTORS IN THE MEMBRANE OF THE POSTSYNAPTIC CELL)
2 Types of Synaptic Junction
1. Electrical Synapse
2. Chemical Synapse
Define Electrical Synapse
- def. a direct electrical connection between two cells, formed by a gap junction, that allows current to pass from one cell to another
- composed of multiple proteins called connexINS
- has no delay
- much less common than chemical synapses
Define Chemical Synapses.
- def. anatomical junction between two neurons, or between a neuron and a muscle or gland where a chemical neurotransmitter is released by the presynaptic neuron which diffuses across the synaptic cleft and binds to receptors on the postsynaptic neuron to exert a physiological response
Mechanism of Presynaptic Release
- neurotransmitter is concentrated into synaptic vesicles in the presynaptic terminal, and is released through exocytosis when the vesicles fuse with the plasma membrane
Mechanism of Postsynaptic Response
- referred to as a post-synaptic-potential (PSP)
- this response most commonly consists of a rapid and graded change in membrane potential in the postsynaptic neuron
2 categories of PSPs
1. EPSP(Excitatory Post
Synaptic Potentials)
2. IPSP (Inhibitory Post
Synaptic Potentials)
Define EPSP.
def. a depolarizing potential that tends to bring the cell towards threshold for generation of an action potential
Define IPSP.
def. a hyperpolarizing potential that tends to bring the cell away from threshold for generation of an action potential
Means of Removing Transmitter
- degradation by nz present in the synaptic cleft
- transported back into the presynaptic neuron by active transport
- diffuse out of the cleft
Action of Drugs on Nervous System
- either antagonistic or facilitory
- transmitter release - tetanus toxin degrades vesicle fusion
- transmitter uptake - Cocaine blocks the reuptake of Dopamine
- SSRIs (selective seratonin reuptake inhibitor)
- transmitter removal - many insecticides block the degradation of ACh
- EPSP - Curare blocks the postsynaptic action of ACh at the neuromuscular junction
- IPSP - Valium enhances the postsynaptic action of GABA
- 2nd messenger - Caffeine enhances the action of cAMP at adrenergic synapses
Purpose of Synaptic Interaction and Neuronal Integration
- to receive the thousands of synaptic input using only a simple mean of integration
Define Convergence
def. the synaptic input of many neurons on to one neuron
Define Divergence.
def. the synapic output of one neuron onto many neurons
Define temporal summation.
def. the additive effect of PSPs occuring close together in time
Define spatial summation
def. the additive effect of PSPs occuring together on nearby parts of the same cell
Define presynaptic inhibition
def. synaptic inhibition of a synaptic terminal causing a decrease in transmitter release