NEUROTRANSMISSION ACROSS THE SYNAPSE

Question 1

What are the types of synaptic transmission

Answer 1

• Electrical transmission

- Chemical transmission

Question 2

Describe electrical transmission

Answer 2

• smaller space between pre- and post synaptic neuron than chemical synapses
• rapid transmission
• hormones secreting neurons in the mammalian hypothalamus

Question 3

Describe chemical transmission

Answer 3

• neurons separates by synaptic clefts
• presynaptic membranes contain synaptic vesicles which contain neurotransmitters
• most neurons in the mammalian nervous system
• available drugs target chemical synapses

Question 4

How are neurotransmitters are released

Answer 4

1. Action potential depolarises the presynaptic terminal
2. VG Ca2+ channels in the presynaptic membrane open, Ca2+ diffuses into the cell
3. Neurotransmitter containing vesicles will fuse their membranes with the presynaptic membrane
4. Neurotransmitter is released

Question 5

How do neurotransmitter work

Answer 5

1. Once released binds with receptors on the post synaptic membrane, cation channels open, Na+ enter
2. Action potential is propagated
3. Excess neurotransmitter broken down by enzymes

Question 6

What are the major classes of neurotransmitters

Answer 6

• amino acids
• amines
• small-molecule neurotransmitter
• neuropeptides

Question 7

What are the classes of receptors

Answer 7

• ionotropic or ligand-gated receptors

- metabotrophic or G-protein coupled receptors (take longer to open than ionotropic)

Question 8

How is neurotransmitter release regulated

Answer 8

• simulation or inhibition of synthesis
• stimulation or inhibition of trip take and/or metabolism
• auto receptors (presynaptic or somatodentritic ): positive and negative feedback- controls release of neurotransmitter

Question 9

What happens to neurotransmitters once AP sent

Answer 9

• Degraded
• Hydrolysed
• Presynaptic reputable and reuse
• Reuptake and metabolism/reuse into presynaptic cleft