The Central Nervous System

The Central Nervous System

Neuron Neuron

The basic functional unit of the The basic functional unit of the CNS CNS

Exhibits excitabilityExhibits excitability Exhibits conductivity Exhibits conductivity

The microscopic gap separating The microscopic gap separating neuronsneurons

SynapseSynapse

Neurotransmitters Neurotransmitters

A chemical substance capable A chemical substance capable of transmitting an impulse of transmitting an impulse across the synaptic cleft across the synaptic cleft

Contained in small sacs called Contained in small sacs called vesicles vesicles

Variety of neurotransmitters Variety of neurotransmitters

Cause Cause acuteacute CNS reaction CNS reaction Small moleculeSmall molecule Rapidly actingRapidly acting

Which are these?Which are these?

ANSWERS:ANSWERS:

AcetylcholineAcetylcholine Dopamine, Epinephrine, Dopamine, Epinephrine,

Norepinephrine, Serotonin Norepinephrine, Serotonin Asparate, Gamma- Asparate, Gamma-

aminobutyric acid (GABA), aminobutyric acid (GABA), Glutamate, Glycine Glutamate, Glycine

Variety of neurotransmitters: Variety of neurotransmitters:

Causes prolonged CNS Causes prolonged CNS reactions reactions

Large moleculeLarge molecule Slow actingSlow acting

Which are these?Which are these?

Answers: Answers:

Adrenocorticotropic hormone Adrenocorticotropic hormone (ACTH)(ACTH)

InsulinInsulin

Factors: Factors:

Synaptic fatigueSynaptic fatigue UpregulationUpregulation DownregulationDownregulation

Dysfunction Dysfunction

Excessive stimulation:Excessive stimulation:

1. Muscle cramps1. Muscle cramps

2. Convulsions2. Convulsions

3. Psychotic symptoms3. Psychotic symptoms

4. Hallucinations4. Hallucinations

5. Tension5. Tension

And........And........

Depression results in:Depression results in:

1. Decreased levels of 1. Decreased levels of consciousness consciousness

2. Respiratory depression2. Respiratory depression

Narcotics and Analgesics Narcotics and Analgesics

Mechanism of action:Mechanism of action:

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

Analgesics & Antipyretics Analgesics & Antipyretics

Mechanism of action:Mechanism of action:

Inactivates cyclooxegenayse Inactivates cyclooxegenayse which prevents prostaglandin which prevents prostaglandin formationformation

Sedatives & Hypnotics Sedatives & Hypnotics

BarbituratesBarbiturates BenzodiazepinesBenzodiazepines Nonbarbiturates & Nonbarbiturates &

NonbenzodiazepinesNonbenzodiazepines

Mechanism of Action Mechanism of Action

BarbituratesBarbiturates Inhibits functionInhibits function

of nerve cellsof nerve cells

BenzodiazepinesBenzodiazepines Bind with Bind with

receptors to receptors to increase the increase the effects of GABAeffects of GABA

Antianxiety Drugs Antianxiety Drugs

Benzodiazepines are the most Benzodiazepines are the most commoncommon

Mechanism of action:Mechanism of action:

Facilitate the inhibitory effects Facilitate the inhibitory effects of GABAof GABA

Antidepressant Drugs Antidepressant Drugs

Types of drugs:Types of drugs:

1. Tricyclic antidepressants1. Tricyclic antidepressants

2. SSRI2. SSRI

3. MAOI3. MAOI

Mechanism of Action Mechanism of Action

Increases the amount of Increases the amount of neurotransmitters neurotransmitters

(serotonin & epinephrine)(serotonin & epinephrine)

Antipsychotics Antipsychotics

Treats psychotic processesTreats psychotic processes Mechanism of action:Mechanism of action:

Decreases the effects of Decreases the effects of Dopamine by occupying Dopamine by occupying receptor sitesreceptor sites

Anticonvulsants Anticonvulsants

Treats seizure disordersTreats seizure disorders Mechanism of action is unclearMechanism of action is unclear

May: May:

1. Decreases neuronal 1. Decreases neuronal excitability excitability

2. Prevents spread of impulses2. Prevents spread of impulses

Alcohol Alcohol

Depresses the CNSDepresses the CNS Rapidly absorbed from the Rapidly absorbed from the

stomach and small intestinesstomach and small intestines Quickly distributed to all body Quickly distributed to all body

tissuestissues