Lecture 23: The Synapse Flashcards
1
Q
Can there be multiple action potentials in one neuron?
A
- Yes
2
Q
An analogy for an action potential moving down the axon….
A
- A Mexican wave
3
Q
What is a synapse?
A
- The junction between nerve cells, where a nerve impulse is transferred from one neuron to another
4
Q
What are some features of the electrical synapses?
A
- Small gap between two neurons
- Connected by tight junctions and form a tunnel
- PHYSICAL DIRECT CONNECTION
- Direct propagation of Action Potential
- V FAST synapse
5
Q
What are some features of the chemical synapses?
A
- Synaptic cleft
- Physical gap
- Neurotransmitters
- Indirect propagation of Action Potential
- Slower than electric synapses
6
Q
What are the two different types of synapses?
A
- Electrical
- Chemical
7
Q
Nerve to muscle synapse is called the….
A
- Neuromuscular junction
8
Q
What are the key components of the chemical synapse?
A
- Presynaptic cell ‘output zone’
- Synaptic knob
- Synaptic cleft
- Postsynaptic cell ‘input zone’ (voltage gated Na+ K+, stimulus gated Na+)
- Voltage gated Ca2+ channels
- Vesicles w/ Neurotransmitters
- Cytoskeleton
- Mitochondria (responsible for production of ATP)
9
Q
What is the importance of Calcium?
A
- Important for bones and the nervous system
- Triggers the release of vesicles
- VERY low concentrations intracellularly
10
Q
How is the signal transmitted?
A
- Neurotransmitter diffuses across synaptic cleft to reach postsynaptic membrane
- Binds to specific receptors
- If Na+ channels are open depolarisation in postsynaptic cell occurs (initiate things)
- If K+ channels open then repolarisation occurs
- If neurotransmitters bid to Cl- channels then hyperpolarisation occurs (shuts things down)
11
Q
In signal transmission what happens if depolarisation is going on?
A
- An excitatory signal
