Nerves 5 Flashcards
What does the action potential in the presynaptic terminal cause in the NMJ?
- Voltage gated calcium channels open and calcium enters the cell
What does the calcium in the pre synaptic terminal cause?
- Allow vesicles containing neurotransmitters to be exocytosed
What is the neurotransmitter that is released at the NMJ?
- ACh
What does the ACh at the synapse do?
- Diffuses across
- Binds to nicotinic receptors
What does the binding to the nicotinic receptors do?
- Opens ligand gated Na/K channels
- Evokes a local potential
What is the local potential of the NMJ called?
End plate
What does the end plate potential always do?
- ALWAYS triggers an AP
How is ACh removed from the synapse?
- Acetylcholinesterase
- Choline groups are reuptaken
What does tetrodotoxin do?
Blocks sodium channels so AP’s can’t be generated
What does joro spider toxin do?
Blocks calcium channels so calcium dependent exocytosis of ACh can’t occur
What does botulinum toxin do?
- Prevents vesicle fusion
What does curare do?
Blocks ACh receptors
What do anticholinesterases do?
- Prevent the action of acetylcholinesterase
- Increase time that ACh is in the synaptic cleft
4 qualities of the CNS synapses that make them more complex than the NMJ?
- Multiple neurotransmitters
- Complex connectivity
- Different postsynaptic potentials
- Many different anatomical arrangement of synapses
What does the range of post synaptic potentials in the CNS allow?
Complex synaptic integration
