Transcript Nervous System

Nervous System
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Central Nervous System: consists of the
brain and spinal cord. It reacts to
internal and external stimuli.
Peripheral Nervous System: Consists of
neurons. It carries messages to and
from the central nervous system.
Autonomic Nervous System: Consists of
neurons. It carries impulses that
regulate involuntary activities and
release of hormones.
Neuron
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Neuron: The basic unit of structure and
function in the nervous system.
It consists of 3 parts.
1) The cell body contains the nucleus
and organelles of the cell.
2) The dendrites are branching fibers
that carry impulses toward the cell body.
3) The axons are long fibers that carry
impulses away from the cell body.
Neuron
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Mylin: Some neurons have a fatty mylin
sheath that serves as insulation.
Nerves
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The nervous system is made up of 3
types of nerves.
1) Sensory nerves carry impulses to the
spinal cord and brain.
2) Motor nerves carry impulses from the
central nervous system.
3) Interneurons (Association neurons):
located in the brain and spinal cord.
Carry impulses from sensory neurons to
motor neurons.
Nerve Impulses
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Nerve impulse: an electrical signal that
moves along a neuron.
Synapse: The gap between an axon and
a dendrite.
Neurotransmitter: chemical that is
released by the axon at the synapse in
order to stimulate the dendrite or
muscle tissue.
The Brain
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Meninges: a series of three membranes
that surround and protect the brain.
Cerebrum: The largest part of the brain.
It is divided into 2 hemispheres.
The left hemisphere controls the right
side of the body. It controls the use of
language, math and logical thinking.
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The Brain
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The right hemisphere controls the left
side of the body. It controls musical and
artistic abilities as well as emotions.
The outer surface is made of gray
matter. It consists of nerve cell bodies.
The inner surface is made of white
matter. It consists mostly of axons.
The Brain
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The cerebellum is located below the
cerebrum. It controls balance and
coordination, as well as involuntary
activities.
The medulla oblongata connects the
brain to the spinal cord, thus it is called
the brain stem. It maintains breathing
and the heart rate. It controls coughing,
sneezing and swallowing.
The Brain
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Thalamus: Oval structure located in
about the middle of the brain. It
interprets pain, temperature and
pressure.
Hypothalamus: Located below the
thalamus. Despite its small size, it
controls many body activities, most of
them related to maintaining
homeostasis. It regulates the endocrine
(hormonal) system.
Spinal cord
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The spinal cord connects the brain to
the rest of the nervous system.
The reflex arc is a pattern of stimulus
and response that involves sensory
impulses to the spinal cord and out
going motor impulses to the muscles.
Disorders of the Nervous
System
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Cerebral palsy: A group of
nonprogressive nerve disorders caused
by damage to motor areas of the brain
during fetal life, birth, or infancy.
Meningitis: Inflamation of the
meninges.
Polio: viral infection that may result in
the destruction of motor neurons
leading to paralysis.
Disorders of the Nervous
System
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Multiple Sclerosis: The progressive
destruction of the mylin sheaths. Leads
to progressive loss of motor control.
Epilepsy: This is the second most
common neurological disorder after
stroke. Results in epileptic seizures
initiated by abnormal discharges of
impulses from the neurons in the brain.