Lecture 10

Question 1

What are the two types of synapses

Answer 1

Electrical (gap junction, current flows directly)

Chemical –> electrical signal converted into chemical signal for transmission to postsynaptic cell

Question 2

What happens at the synapse

Answer 2

AP depolarizes axon terminal, opens voltage gated Ca channels, influx of Ca causes release of neurotransmitter through exocytosis, neurotransmitter diffuses across synaptic cleft and binds to receptors

Question 3

How is the stimulus terminated

Answer 3

reuptake by the neuron or glial cell, enzymatic breakdown, diffusion

Question 4

What are the 5 requirements for a neurotransmitter?

Answer 4

must be found in presynaptic cell
when applied directly to postsynaptic cell, must have same effect
must be released in response to presynaptic depolarization
must act on specific receptors
chemical signal must be terminated

Question 5

How is stimulus strength coded for?

Answer 5

frequency of action potentials and amount of neurotransmitter released

Question 6

What are the 2 postsynaptic responses

Answer 6

excitatory postsynaptic potential or inhibitory postysynaptic potential

Question 7

How can modulation occur?

Answer 7

presynaptic (no response at specific presynaptic axon terminal) or postsynaptic (no response at postsynaptic axon terminal)

Question 8

What are 3 synaptic diseases

Answer 8

Myasthenia gravis –> autoimmune mediated disease caused by lack of Ach receptors resulting in muscle weakness and fatigue. Treated through anti-cholinesterase to prevent breakdown of Ach

Parkinsons –> lack of dopamine from substantia nigra cells in basal ganglia. results in tremors, hyperkinesia. treated with dopamine precursors, preventing degradation

Depression –> lack of serotonin. treat with serotonin reuptake inhibitors