How neurotransmission is achieved in brain
3 important questions on How neurotransmission is achieved in brain
Name 6 signs of electrical transmission
An electrical synapse has a small (4 nm) distance between pre- and post synaptic cell. There is cytoplasmatic continuity. There are gap-junction channels. The agent of transmission is via ionic current. The synaptic delay is virtually absent and the direction of transmission is bidirectional
Name 6 signs of chemical transmission
A chemical synapse has a 'larger'distance between pre- and postsynaptic cell membranes (20-40 nm). There is NO cytoplasmatic continuity. The ultrastructural components are presynaptic vesicles, active zones; postsynaptic receptors. The agent of transmission is via chemical transmitter. The synaptic delay is at least 0.3 ms, usually 1-5ms. The direction of transmission is unidirectional!
What is the mechanism behind a chemical synapse in 6 steps?
Step 1: Action potential arrives at axon terminal
Step 2: Voltage-gated Ca2+ channels open and Ca2+ enters the axon terminal
Step 3: Ca2+ entry causes neurotransmitter-containing synaptic vesicles to release their contents by exocytosis
Step 4: neurotransmitter diffuses across the synaptic cleft and binds to ligand-gated ion channels on the postsynaptic membrane
Step 5: binding of neurotransmitter opens ligand-gated ion channels, resulting in graded potentials
Step 6: reuptake by the presynaptic neuron, enzymatic degradation, and diffussion reduced neurotransmitter levels, terminating the signal
Step 2: Voltage-gated Ca2+ channels open and Ca2+ enters the axon terminal
Step 3: Ca2+ entry causes neurotransmitter-containing synaptic vesicles to release their contents by exocytosis
Step 4: neurotransmitter diffuses across the synaptic cleft and binds to ligand-gated ion channels on the postsynaptic membrane
Step 5: binding of neurotransmitter opens ligand-gated ion channels, resulting in graded potentials
Step 6: reuptake by the presynaptic neuron, enzymatic degradation, and diffussion reduced neurotransmitter levels, terminating the signal
The question on the page originate from the summary of the following study material:
- A unique study and practice tool
- Never study anything twice again
- Get the grades you hope for
- 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
