Transcript Cells of the Nervous System

The Nervous System & its Cells
Divisions of the Nervous System
Central (inside skull & spine)
Brain
Spinal Cord
Peripheral (outside skull & spine)
Nerves
Central Nervous System
Brain
Divisions of the human brain
Specialization of function
Different regions of the brain are associated with different function
Ouch! That hurts, dude!
Spinal Cord Reflex
Spinal cord
lesion
- Would sensation be abolished by:
- a spinal cord lesion?
- polio?
- Would the reflex be abolished by:
- a spinal cord lesion?
- polio?
Peripheral Nervous System
Somatic System:
- controls voluntary muscle
Autonomic System:
- controls glands & internal organs
- has two subcomponents
- Sympathetic (adrenaline): arousal
- Parasympathetic: calm
Levels of
Investigation
Brain Areas
(visual system)
Cells
(neurons)
Molecules
(neurotransmitters)
Neurons: Its many shapes & sizes
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Neuron: basic parts
Cell Body
Dendrite
Axon
Axon
Cell membrane
Synaptic cleft
football field
Campus
wide a street
long as Philly - Ohio
thick as pinky finger
thick as thumb
axon terminals
# synapses
10.000 (same number as Villanova students)
Some axons are wrapped burrito-style by fatty cells (glial cells)
- increases speed at which neurons communicate)
- white in color (white matter vs gray matter
- is destroyed by multiple sclerosis
Neuron: its physiology
What makes neurons
different from other cells?
Neurons process and
transmit electrical impulses
Neuron’s cell membrane is
electrically charged
(interior is more negative)
Neurons influence each
other’s charge (‘communicate’)
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How do neurons
process and transmit
electrical impulses?
A. dendrites receive input
from other neurons
B. axon sends neural
impulse to axon terminal
C. a neurotransmitter (NT)
is release and makes
contact with another neuron
(synapse)
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Synapse
Communication Steps
•
NT is released from
pre-synaptic neuron
•
NT binds to receptors
in post-synaptic neuron
•
Opens Na+ channels
•
Sodium rushes in
(activation)
•
If enough Na+ rushes
in => depolarization
(action potential)
•
NT released by postsynaptic neuron
Pre-synaptic neuron
Post-synaptic neuron
Other important facts
Various Neurotransmitters (NT):
-
Dopamine
Adrenaline
Serotonin
Acetylcholine
For each NT,various receptors
- nicotine & muscarine
Drugs can act by
- modifying amount of NT, or
- binding to receptor (nicotine)
The net effect on neuron could be:
- activation (action potential)
- inhibition