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NERVOUS SYSTEM
Essential question: What are the differences between
responses with the nervous system versus responses
with the endocrine system?
In humans, as in other animals, regulation is
achieved by the integration of the nervous
and the endocrine system. The nervous and
endocrine systems if humans show certain
similarities and certain differences.
Similarities:
•Both secrete chemical messengers.
•The nervous system secretes
neurotransmitters and the endocrine
system secretes hormones.
Both play a major role in homeostasis.
Differences:
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Nerve responses are more rapid than the
endocrine responses.
Nerve responses are shorter in duration
than endocrine responses.
Nerve responses travel through the
nervous system and endocrine responses
travel through the circulatory (blood)
system.
Essential questions: What are the three types of
neurons? What is the function and location of
each type?
Functional Organization:
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The neuron is the basic unit of structure
and function of the nervous system.
The nervous system is composed of
three different neurons.
The Three Types of Neurons:
• Sensory neuron
• Interneuron
• Motor neuron
Neurons
Sensory neuron-transmits impulses from
receptors to the central nervous system
(brain and spinal cord).
Receptors-Sense organs where sensory
neurons are concentrated. Exs. Eyes,
ears, nose, tongue, and skin.
Interneurons:
Located mainly in the CNS (brain and
spinal cord).
Interprets impulses (messages).
Relays impulses to motor neutrons.
Motor neurons: transmits impulses from the
CNS to effectors
Effector:. A cell, tissue, or organ, which
produces a response to a stimulus.
Exs. Muscles and glands
Essential Question: What is a nerve?
Nerves: bundles of
neurons that are
specialized for long
distances and highspeed impulse
transmission. Ex.
Optic nerve
Optic Nerve
Sciatic Nerve
Parts of a Neuron:
Essential questions: What are the parts of a
neuron? What is the function of each of these
parts?
Parts of a Neuron:
Every neuron is composed of:
•Dendrites
•Cyton (cell body)
•Axon
•Terminal branches (end branches)
Dendrites:
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Receive impulses.
• Carries impulses
towards the cyton.
Axon:
•
Carries impulses
away from the
cyton.
• Protected with a
myelin sheath
Essential question: How are impulses transmitted
from one neuron to the next?
Impulse Transmission:
Essential Questions: What is a synapse? What is
the relationship between a synapse and a
neurotransmitter?
Synapse-space between two neurons.
Neurotransmitters:
► Chemical released by terminal branches of
one neuron.
► Starts a new impulse in next neuron.
► 30 different known neurotransmitters. Exs.
Acetylcholine, norepinephrine
Nerve Transmission
Nerve Transmission
Essential question: What are the parts and
functions of the brain?
The Brain
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The brain weight
approximately 1.5 kg,
but uses 25 % of the
body’s oxygen supply.
It is composed of
billions of
interconnecting
neurons.
The brain is protected
by 3 membranes
(Meninges) and fluid.
The brain is
composed of three
main parts:
Cerebrum
Cerebellum
Medulla
Parts of the Brain
Cerebrum:
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Largest part of the
brain.
Composed of two
halves (hemispheres).
Contains many
convolutions (folds).
Functions include:
Controls voluntary
movement (skeletal).
Intelligence
Memory
Speech and language
Senses
Cerebellum and Medulla
Located in the back portion of the brain.
Functions include:

Balance

Posture
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Coordination
Medulla:
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Located at the top of the spinal cord.
Functions include:

Controls and coordinates involuntary activity. Exs.
Breathing, heart rate, peristalsis, and blood pressure
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Essential Questions: What is the CNS? What is
structures make up the CNS?
 The CNS is
composed of the
brain and the
spinal cord.
Spinal Cord:
a. Protected by vertebrae of the spinal
column
b. Relays impulses to and from the brain.
c. Controls certain reflexes.
Essential Questions: What is the PNS? What is a reflex
arc? How does a reflex arc help to maintain
homeostasis?
Peripheral Nervous System
(PNS)
a. Located outside of
the CNS.
b. Made up of all of the
neurons and nerve
fibers outside the
brain and spinal cord.
Reflex Arc
Essential question: What are some diseases that
are associated with the nervous system?
Diseases of the Nervous System:
Cerebral Palsy:
• Name for a collective group of disorders
that affect a person’s control of motor
functions.
• Caused by brain damage just before of
after birth.
What do these three men have in
common?
Multiple Sclerosis
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Destruction of the
myelin sheath.
Symptoms include
shaking of hands,
blurred vision, and
slurred speech.
May appear and
disappear for years.
Alzheimer’s Disease:
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Cause unknown.
Progressive, degenerative disease.
Eventual memory lost, inability to
think, speak, or care for oneself.
Usually fatal.
Parkinson's Strikes Again!!!
Parkinson’s disease:
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Cause unknown.
Neurons can no longer produce the
neurotransmitter-dopamine.
Symptoms include: tremors, poor balance,
lack of coordination, stiffening of muscles.
One million people in the us have
Parkinson’s and 600,000 people are
diagnosis with it annually.
On set is usually over the age of 60.
The Many Faces of Parkinson’s