Transcript Structure and Function of the Central Nervous System

Psychopharmacology
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Complex
1.4 kg in weight
Pre frontal cortex
2% of body weight
20% of oxygen
15% of our cardiac input
10% of all energy
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Brain protection system
The BBB is both;
 A physical barrier that
restricts the entrance of
potentially harmful
substances
 A system of cellular transport
mechanisms that controls the
entrance of essential nutrients
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Cerebrum and Cerebral cortex
Left and Right Hemispheres
Left Hemisphere- dominant hemisphere
 Production of language
 Mathematical ability
 Problem solving
•Right Hemisphere
- Creativity
- Spatial ability
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Located at the front of both cerebral
hemispheres
Primary motor cortex
Pre motor cortex
Broca’s Area
Complex Functioning – personality,
judgement, insight, reasoning, problem
solving, abstract thinking and working
memory
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Located behind frontal lobe
Somatosensory cortex
Spatial orientation, perception and
comprehension of language function
recognising objects by touch
Links visual and somatosensory information
together
Neglect
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Located et each side of the brain
Involved in receiving and processing auditory
information, higher order visual information ,
complex aspects of memory and language
Wernicke’s area
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Visual processing area
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Corpus Callosum
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Thalamus
• Filter for sensory
information
• Control of mood
states
• Body movement
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Hypothalamus
• Central control
• Regulate autonomic,
emotional, endocrine
and somatic function
• Stress
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Cerebellum
 Equilibrium
 Muscle tone
 Postural control
 Coordination of muscle movement
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Pons
 Relay station
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Medulla Oblongata
Skeletal muscles
Balance
Coordination
Inner ear sound
impulses
• Heart rate, vomiting,
sneezing
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Reticular formation
• Arousal
• Circadian rhythm
• respiration
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Basal ganglia
 Muslce tone
 Posture
 Movement
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Substantia Nigra
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Amygdala
 Mood
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Hippocampus
 Memory
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The structural unit of the brain
Cell body
Axon
Dendrites
Synapse
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The Information that flows in the neurone
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Approximately 10 billion neurons are responsible
for receiving, organising and transmitting
information in the central nervous system
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Ions in the intracellular fluid (inside the cell) have
a negative charge
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Ions in extracellular fluid (outside the cell) have a
positive charge attracting positively charged cells
(cations)
‘Potential difference’ between the inside and the
outside of the cell
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Ions are sodium, potassium, calcium and
chloride
‘voltage gated’
Resting Potential vs. Action potential
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The flow of neurotransmitter across the
synapse
Neurotransmitter;
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Made in the pre synaptic neurone
Stored inactively in synaptic vesicles
Released from the synaptic vesicles into the synapse
Binds to receptors
Binds to reuptake transporters to be taken back into the
neurone
 Is degraded by specific enzymes
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Acetylcholine (ACh)
Norepinephrine (NE)( also known as
noradrenaline)
Dopamine(D)
Serotonin (5HT)
Glutamate
Gamma-aminobutyric acid (GABA)
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There are two kinds of neurotransmitters –
INHIBITORY and EXCITATORY.
stimulate the brain
calm the brain
• Cholinergic pathways
• thought to be involved in
cognition (esp. memory) and
our sleep/wake cycle
• parasympathetic nervous
system regulating bodily
functions such as heart rate,
digestion, secretion of saliva
and bladder function
• Alzheimer’s disease and
myathesia gravis (weakness of
skeletal muscles)
• Anti-cholinergic effects
• attention, alertness and arousal
• NE levels fluctuate with sleep
and wakefulness and changes in
attention and vigilance
• mood, affective states and
anxiety
• antidepressant
• complex movement and cognition
• Emotional responses such as
euphoria or pleasure (seen in
amphetamine/cocaine use).
•Significant role in motor control
•EPSE’s
• Great influences on behaviour.
• Low serotonin activity is
associated with aggression,
suicide, impulsive eating and disinhibited sexual behaviour
• modulating general activity
levels of the CNS, particularly the
onset of sleep
• depression and anxiety
disorders
• delusions, hallucinations (LSD)
• negative symptoms of
schizophrenia
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Glutamate is found in all cells of the body
control the opening of ion channels that allow
calcium to pass into nerve cells producing
impulses
Blocking of glutamate receptors produces ( eg.
By PCP) schizophrenic like symptoms
Over exposure of neurons to glutamate cause
cell death seen in stroke and Huntington’s
disease (PN).
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Inhibitory and its pathways are only found
within the CNS.
control excitatory neurotransmitters in the
brain and controlling spinal and cerebral
reflexes.
anxiety disorders
decreased GABA can lead to seizure activity
Benzodiazepines and barbiturates sedative
medication act on GABA