Nervous system

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Nervous system

• Termination of neurotransmitter activity
• Integration of Neural Information Transfer
• Read ahead for chapter 10 Sensory systems
• general properties (pgs 282- 286)
• Chemoreception (pgs 295 298)
• The eye and vision (pgs 309 319)

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Neurotransmitter activity is quickly terminated

• Acetylcholine is broken down by
  acetylcholinesterase

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Neurotransmitter activity is terminated

• Norepinephrine is actively transported back to
  the pre-synaptic axon
• CNS neurotransmitters (amines, peptides, amino
  acids) move into circulation or transported to
  pre-synaptic terminal.

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The relationships between many neurons

• Integration
• Information flows in the nervous system

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What happens when there are many synaptic inputs
ocurring?
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Excitatory post-synaptic potential

• Synaptic junction
• Binding of neurotransmitter leads to
  depolarization of the post-synaptic cell
• EPSP, excitatory post synaptic potential

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Post-synaptic inhibition

• At a synaptic junction
• The binding of the neurotransmitter causes
  hyperpolarization
• IPSP inhibitory post synaptic potential

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Post-synaptic inhibition
-At a synaptic junction - The binding of the
neurotransmitter causes hyperpolarization -
IPSP inhibitory post synaptic potential
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Three synaptic junctions, each release an
excitatory neurotransmitter
spatial summation
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Three synaptic junctions, 2 are stimulatory, 1 is
inhibitory.
spatial summation
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Stimuli are very far apart in time. Stimuli
dont occur often.
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Temporal Summation
Subthreshold stimuli arrive At the trigger zone
within a Short period of time.
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Synaptic Modulation at the axon terminal