Transcript The Nervous System

The Nervous System
Functions, Divisions, &
Neurons
Functions

Sensory Input

Integration

Motor functions
Divisions of Nervous System

Central nervous system (CNS)

Peripheral nervous system (PNS)
Central Nervous System

Brain

Spinal cord
Peripheral Nervous System

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Consists of nerves
and ganglia
Further divided:

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Afferent division
(sensory)
Efferent division
(motor)
Efferent Division of PNS

Further divided:

Somatic nervous system (voluntary)

Autonomic nervous system (involuntary)
Autonomic nervous system

Further divided:

Sympathetic

Parasympathetic
Nerve Tissue

Neuron

Neuroglia (glial cell)
Neuron
Types of Neurons

Afferent (sensory)

Efferent (motor)

Inter-neurons (association neurons)
Neuroglia


Do not conduct
nerve impulses
Serve as protection
and nourishment
for neurons
Nerve Impulses

Resting membrane

Stimulation of neuron
Resting membrane

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Non-conducting neuron
Lots of Na+ outside neuron
Lots of K+ inside neuron, but even
more negative ions found inside
Membrane is polarized
Stimulation of Neuron


A stimulus changes the membrane to
allow passive movement of ions.
Stimulus must be strong enough to
make membrane highly permeable
(threshold).
Action Potential – Nerve
Impulse

Depolarization

Reverse polarization

Repolarization
Action Potential Animation

Nerve Impulse
Conduction of Impulse

Action potential must continue the
length of a neuron

Neurotransmitters carry impulse
across the synaptic cleft to new neuron
Continuous vs Saltatory Action
Potentials
Reflex Arcs



Functional unit of nervous system
Allows for rapid response to stimulus
Components:

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


Receptor
Sensory neuron
Integration center
Motor neuron
Effector