Unit 3: Biological Psychology

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Unit 3 Biological Psychology

• Essential Task 3-3
• Describe the chemical process of transmitting a
  signal between neurons with specific reference to
  the synapse (synaptic vesicles, synaptic cleft
  and receptor sites), neurotransmitters
  (excitatory and inhibitory), drugs (agonists and
  antagonists) and reuptatke.

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We are here
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Essential Task 3-3
Outline

• Chemical communication between neurons
• synapse
• Terminal buttons
• synaptic vesicles
• synaptic cleft
• receptor sites
• neurotransmitters
• Excitatory and inhibitory
• Drugs (agonists and antagonists)
• reuptatke

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Synapse
Outline

• Synapse SIN-aps a junction between the axon tip
  of the sending neuron and the dendrite or cell
  body of the receiving neuron.

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The synapse has 4 key components.
Outline

1. Terminal button - Enlarged area at the axon
   terminal
2. Synaptic vesicles - Sacs in the terminal button
   that release chemicals called neurotransmitters
   into the synaptic space
3. Synaptic space (synaptic cleft) - Tiny gap
   between neurons
4. Receptor sites - Location on receptor neuron
   where neurotransmitters can bind.

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Chemical Communication
Terminal button - Enlarged area at the axon
terminal Synaptic vesicles - Sacs in the terminal
button that release chemicals called
neurotransmitters into the synaptic
space Synaptic space (synaptic cleft) - Tiny gap
between neurons Receptor sites - Location on
receptor neuron where neurotransmitters can bind.
Outline
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Chemical Communication
Outline
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Neurotransmitters

• Neurotransmitters (chemicals) released from the
  sending neuron that travel across the synaptic
  cleft and bind to receptor sites on the receiving
  neuron, thereby influencing it to generate an
  action potential.

Outline
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Neurotransmitters fit like chemical keys in
chemical locks.
Outline
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2 Categories of neurotransmitters
Excitatory and Inhibitory

• Excitatory
• The key fits and opens the receiving neuron.
• Activation of the receptor causes depolarization
  of the membrane and promotes an action potential
  in the receiving neuron.

• Inhibitory
• The key fits in but only stops any other keys.
• Activation of the receptor causes
  hyperpolarization and depresses action potential
  generation.

Outline
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Drugs that excite a neuron are called Agonists
Outline
Agonist excites!!!
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Drugs that inhibit a neuron are called antagonists
Antagonists stops!!!
Outline
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Reuptake
Outline

• Neurotransmitters in the synapse are reabsorbed
  into the sending neurons through the process of
  reuptake. This process applies the brakes on
  neurotransmitter action.

Neurotransmitters are taken back
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Selective Serotonin Reuptake Inhibitors
Outline
Citalopram (Celexa) Escitalopram
(Lexapro) Fluoxetine (Prozac) Paroxetine (Paxil,
Pexeva) Sertraline (Zoloft)