Transcript Neurology - Porterville College

Neurology
Lecture 1
Part 1
The Final Frontier
• Space the final
frontier?
• The brain, the final
frontier!
The nervous system consists of:
•
•
•
•
The Brain
Spinal Cord
Peripheral Nerves
Divided system
– Central Nervous System
(CNS)
• Brain & Spinal Cord
– Peripheral Nervous System
(PNS)
• Nerves (peripheral &
Cranial)
Nervous System
• Controls and
coordinates all parts of
the body
• By transmission of
electrical impulses
(Electrical-chemical
system)
Purpose of the Nervous System
• Control Center
• Communication
Receive evaluate 
respond
• Stimulation of
Movement
• Maintains Homeostasis
– Along with the what
system?
• Endocrine
Function of Nervous System
• Coordination & Control
1. Receive info (stimuli)
2. Computes info 
determines responses
3. Transmit info  action
Neuron
• Basic functional unit
– Afferent neuron
• Sensory
• Carry info from PNS
 CNS
– Efferent neuron
• Motor
• Carry into from CNS
 PNS
Neuron structure
• Cell body/ Soma
– Nucleus
• Dendrites
– Carry impulses toward
the cell body
• Axons
– Carry impulses away
from the cell body
Damaged Neuron
• CNS =
– Irreversible
• PNS =
– will repair itself if the
cell body is not
destroyed
Synaptic Junction
• Neuron connect to
each other end to end
• Where two neurons
come together
– Synaptic junction
– Synapse
– Inter-neuron space
Synaptic Junction
• Terminal end of Axon =
Synaptic Vesicles
• Nerve impulse reaches the
vesicle  release substance 
neurotransmitters into the
synaptic junction
• Nerve impulses must have a
receptor site
Neurotransmitters
• Synthesized in the
soma
• Special Properties
– Excitability
– Inhibitory
– Modify
• 30+ neurotransmitters
Excitatory Neurotransmitters
• Serotonin
–
–
–
–
–
Sleep
Sensory perception
Temperature
Mood
Inhibits pain
Excitatory Neurotransmitters
• Dopamine
– Gross subconscious
movement
– Fine motor skills
– Emotional responses
Excitatory Neurotransmitters
• Norepinepherine
– Maintains arousal
– Overall activity
– Mood
• Acetylcholine
– Vital for short term
memory
– Speeds impulse
transmission
Inhibitory Neurotransmitters
• Cholinergics
– Stabilizers
– Inhibitors
• GABA
• Dopamine
– Basal Ganglia
– Acetylcholine &
Dopamine are opposites
which work together to
create homeostasis
Neuropeptides
• Not neurotransmitters
• Encephalin
• Chemical endorphins
–
–
–
–
Suppress pain
Memory
Learning
Sexual activity
Nerve Impulse
• The nervous system is
powered by electrical
and chemical energy
–
–
–
–
K+
Na+
Cl(Ca+)
Nerve Impulse
•
Absolute retraction
period
– The time interval
phase that occurs
when the neuron
cannot be restimulated