Lecture 3 - Synaptic Transmission Flashcards
1. Be able to list stages of chemical synaptic transmission 2. Be able to describe the mechanism by which excitatory and inhibitory neurotransmitters function 3. Distinguish between action potentials and post synaptic potentials 4. Distinguish between temporal and spatial summation 5. Apply basic neurophysiology principles to the knee jerk reflex neural chain 6. Describe the strengths and weakness of two visualization techniques for viewings neuronal circuits
1
Q
Synapse history (1904)
A
- coined by Charles Scott Sherringham
- Synapse means to join/together
2
Q
Adrenaline (1904)
A
- Adrenaline wasn’t known back then
- Thomas Renton Elliot thought that the EPI substance (Adrenaline) activated/caused a reaction to the symphatetic nervous system: caused it to beat/be stimulated
3
Q
Acetylcholine (Ach)
A
- In 1914/1933
- called muscrinic receptors (thought to be a poison that slowed heart rate and breathing) this is false
- experiment showed that acetylcholine and adrenaline is naturally produced in the brain
- Ach mimicked the parasymphatetic nervous system (relax/calm)
4
Q
Otto Loewi
A
- he wanted to prove chemical reaction in a synapse
- experiment with frogs with 2 hearts, only one heart was conducted on but both hearts had a reaction
5
Q
John Eccles (1951)
A
- electron microscope proved synapse
6
Q
How many types of synpases are there
A
- chemical
- electrical
7
Q
What is a chemical synapse
A
- When a current is injected in the pre-snypactic cell, release of neurotransmitters causes change in the post synaptic cell
- 1.5 seconds longer to work
8
Q
What is an electrical synapse?
A
- transmits signals between neurons as if they are connected
- has a gap junction that acts like a bridge
- current just keeps pushing through both cells
9
Q
advantages of chemical synapse
A
- can control different effects on the post synaptic cell
- diff receptors can accept/reject diff messages (selectivity) and AP dictates the strength of response
- adaptable/flexible
-more information sent
*focus of the course
10
Q
disadvantages of chemical synapse
A
- slower (1.5 seconds longer)
- dependant on neurotransmitter
- need energy (AP) to recycle neurotransmitter
11
Q
advantage of electrical synapse
A
- regulates feedback loops
- found in animals with fast reactions
- more efficient, and fast diffusion of signals between cells
- less plasticity/malleability
12
Q
disadvantages of electrical synapse
A
- less information processing
- go or no go in transmission
13
Q
Explain how Synaptic Transmission works
A
- vesicles dock near plasma membrane
- presynaptic terminal depolarization
- arriving AP causes opening of VG CA2+ channels
14
Q
Explain the Pre-synaptic side of chemical synapse
A
- Pre-synaptic is filled with vesicles full of neurotransmitters
- need an AP to send the message to the post-synapse
15
Q
What is flash freezing of tissues
A
- to visualize synaptic message
- they depolarize a pre-synaptic neuron then flash freeze the tissue so the changes in the tissue STOPS
- helps see the timeframe of depolarization
