The Central Nervous System

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The Central Nervous System
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Neuron

• The basic functional unit of the CNS
  
• Exhibits excitability
• Exhibits conductivity

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Synapse

• The microscopic gap separating neurons

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Neurotransmitters

• A chemical substance capable of transmitting an
  impulse across the synaptic cleft
• Contained in small sacs called vesicles
  

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Variety of neurotransmitters

• Cause acute CNS reaction
• Small molecule
• Rapidly acting
• Which are these?

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ANSWERS

• Acetylcholine
• Dopamine, Epinephrine,
  Norepinephrine, Serotonin
• Asparate, Gamma- aminobutyric acid
  (GABA), Glutamate,
  Glycine

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Variety of neurotransmitters

• Causes prolonged CNS reactions
• Large molecule
• Slow acting
• Which are these?

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Answers

• Adrenocorticotropic hormone (ACTH)
• Insulin

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Factors

• Synaptic fatigue
• Upregulation
• Downregulation

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Dysfunction

• Excessive stimulation
• 1. Muscle cramps
• 2. Convulsions
• 3. Psychotic symptoms
• 4. Hallucinations
• 5. Tension

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And........

• Depression results in
• 1. Decreased levels of consciousness
• 2. Respiratory depression

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Narcotics and Analgesics

• Mechanism of action
• Bind to opiod receptors on cell membranes
  of specific neurons in the brain resulting in
  decreased pain

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Analgesics Antipyretics

• Mechanism of action
• Inactivates cyclooxegenayse which prevents
  prostaglandin formation

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Sedatives Hypnotics

• Barbiturates
• Benzodiazepines
• Nonbarbiturates Nonbenzodiazepines

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Mechanism of Action

• Barbiturates
• Inhibits function
• of nerve cells

• Benzodiazepines
• Bind with receptors to increase the effects of
  GABA

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Antianxiety Drugs

• Benzodiazepines are the most common
• Mechanism of action
• Facilitate the inhibitory effects of GABA

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Antidepressant Drugs

• Types of drugs
• 1. Tricyclic antidepressants
• 2. SSRI
• 3. MAOI

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Mechanism of Action

• Increases the amount of neurotransmitters
  (serotonin epinephrine)

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Antipsychotics

• Treats psychotic processes
• Mechanism of action
• Decreases the effects of
  Dopamine by
  occupying receptor sites

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Anticonvulsants

• Treats seizure disorders
• Mechanism of action is unclear
• May
• 1. Decreases neuronal excitability
• 2. Prevents spread of impulses

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Alcohol

• Depresses the CNS
• Rapidly absorbed from the stomach and small
  intestines
• Quickly distributed to all body tissues