Synapse 1 & 2: Communication Between Cells

Question 1

What is a synapse?

Answer 1

Defined as: a junction between two cells where electrical changes in one cell cause a signal to be passed to another, usually via a chemical NT

+ Majority are chemical synapses, but some are electrical

Question 2

Define pre-synaptic:

Answer 2

+ Relating to or denoting a nerve cell that releases a transmitter substance into a synapse during transmission of an impulse

+ Pre-synaptic neuron is the neuron before the synapse, delivering the “message” across the synapse to the postsynaptic neuron

Question 3

Define post-synaptic

Answer 3

+ A neuron to the cell body or dendrite of which an electrical impulse is transmitted across a synaptic cleft by the release of a chemical neurotransmitter from the axon terminal of a presynaptic neuron.

+ Post-synaptic neuron is the “receiver” of the neurotransmitter “message”.

Question 4

What are the features of the synapse in pre-synaptic cells?

Answer 4

+ Axon of pre-synaptic neuron
+ Axon terminal
+ Synaptic vesicles (contain NT molecules)
+ NT

Question 5

What are the features of the synapse in post-synaptic cells?

Answer 5

\+ Post-synaptic neuron
\+ Synaptic cleft
\+ Receptor sites
\+ Post-synaptic membrane
\+ NT

Question 6

What are the 3 categories synaptic activity can be divided into?

Answer 6

1. Pre-synaptic activity
2. Post-synaptic activity
3. Nerotransmitter inactivation

Question 7

What is the process of chemical neurotransmisson in a small-molecule transmitter

Answer 7

1. Synthesis enzymes in cell body
2. Slow axonal transporty if enzymes
3. Synthesis and packaging of NT
4. Release and diffusion

Question 8

What is the process of chemical neurotransmisson in a peptide transmitter?

Answer 8

1. Synthesis of neurotransmitter precursors and enzymes
2. Transport of enzymes and pre-peptide precursors down microtubule tracks
3. Enzymes modify pre-peptides to produce peptide NT
4. NT diffuses away and is degraded by proteolytic enzymes