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The Nervous System
Unit 1 Lesson 5 The Nervous and Endocrine
Systems
Essential Question: How do the nervous and
endocrine system work?
Copyright © Houghton Mifflin Harcourt Publishing Company
The Nervous System
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What is the function of the nervous system
The nervous system is made up of the
structures that control actions and reactions of
the body in response to stimuli in the
environment.
The nervous system receives and sends out
information about activities within the body and
outside your body.
It directs the way in which your body
responds to this information.
It also monitors and responds to changes in the
environment.
helps maintain homeostasis
The Nervous System
• The CNS is made up of
the brain and spinal cord.
• The brain is the body’s
central command organ.
• The spinal cord allows
the brain to communicate
with the rest of the body.
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• The PNS connects the CNS
to the rest of the body.
• Sensory and Motor parts
• Involuntary processes are
those you have no control
over, such as your heart
beating.
• Voluntary processes are
actions your brain can
control, such as moving an
arm or a leg.
Both the CNS and PNS are both made of
neurons
The Nervous System - Divisions of the Nervous System
What are the parts of the CNS?
There are three main regions
of the brain that receive and
process information.
These are:
*cerebrum,
* cerebellum,
*brain stem (medulla)
The Brain
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The Nervous System
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Cerebrum
The largest part of the brain
is called the cerebrum.
Functions:
 Store memories
 Perform voluntary movements
 Allow you to sense the environment
 Think
 Problem solve
The Nervous System
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Cerebellum
The second largest part of your
brain is called the cerebellum
Functions:
Process information from your body
coordinates the actions of your muscles
helps you keep your balance
When you walk, the impulses that tell your
feet to move start in your cerebrum.
However, your cerebellum gives you the
muscular coordination and sense of balance
that keep you from falling down.
The Nervous System
Medulla / Brain Stem
The brain stem,
connects your brain to
the spinal cord.
controls your body’s
involuntary actions
 Breathing and heart
rate, blood pressure,
body temperature
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The Nervous System
Spinal Cord
The spinal cord is a bundle
of nerves protected by bones
called vertebrae.
Nerves are a collection of
nerve-cell extensions bundled
together with blood vessels
and connective tissue.
The spinal cord carries
messages to and from the
brain.
Link between PNS & Brain
Sensory information flows in and
motor information flows out
towards the muscles
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The Nervous System - How the Nervous System Works
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How do signals move through the nervous
system?
Neuron: A cell that moves messages in
the form of fast-moving electrical energy
(Impulses)
The Nervous System
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Types of Neurons
Sensory Neuron, Interneuron, and Motor Neuron
A sensory neuron picks up
stimuli from the internal or
external environment and
moves the information to the
spinal cord to the brain.
The brain interprets the
information
A motor neuron sends an
impulse to a muscle or gland,
and the muscle or gland reacts
in response.
The Nervous System - How the Nervous System Works
What are the parts of a neuron?
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The Nervous System
Neuron Part
Cell Body
Dendrites
Axon
Axon terminal
Structure
Visualize it!
Function
Region containing Gathers
information from
nucleus and
dendrites
organelles
Gathers
Branches of the
information from
cell body
other cells
Send impulses
Long branch
away from the
from the cell
cell body
body
End of an axon
Changes
electrical signal to
chemical signal
The Nervous System - How the Nervous System Works
How a Nerve Impulse Travels
When a nerve impulse travels
along a neuron or from one
neuron to another, it does so in
the form of electrical and
chemical signals.
For a nerve impulse to be carried
along at a synapse, it must cross
the gap between the axon and
the next structure. The axon tips
release neurotransmitters that
carry the impulse across the gap.
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The Nervous System
NS Functions
Numbers from top to bottom
3 cerebrum
1 cerebellum
2 medulla/brainstem
4 spinal nerves
5 spinal cord
1) Cerebellum
2) Medulla / brainstem
3) Cerebrum
4) Spinal nerves
5) Spinal cord
CNS Review
1)
2)
3)
4)
5)
6)
7)
8)
9)
Brain Stem/medulla
Spinal Cord
Cerebrum
cerebellum
Medulla/brainstem
Axon
Nucleus
Neuron
Dendrite
The Nervous System
The body senses the environment with
specialized structures called sensory
organs
What are the main senses?
Sight
Touch
Hearing Taste
Smell
The Nervous System
What are the main senses?
• Sight allows you to see
objects (size and shape),
motion, and color.
• The front of the eye is
protected by a membrane
called the cornea.
• Light passes through an
opening called the pupil.
• Light-sensitive receptor cells,
called rods and cones, in the
retina change light into
electrical impulses that are
sent to the brain.
Unit 1 Lesson 5
The Nervous System
The Nervous and Endocrine Systems
That Makes Sense!
What are the main senses?
• Impulses travel to your brain, creating an awareness
of touch called a sensation.
• The skin has different kinds of receptors that detect
pressure, temperature, pain, and vibration.
The Nervous System
What are the main senses?
• Hearing happens when sound-wave vibrations are turned into
electrical impulses in the ear.
• Sound is funneled through the outer ear, making the eardrum
vibrate.
• Tiny bones in the ear
vibrate, causing the fluid
in the cochlea to move
in waves.
• Hair cells in the fluid
cause neurons to send
electrical impulses to the
brain via the auditory
nerve.
The Nervous System
What are the main senses?
• The tongue is covered with
taste buds that contain
taste cells. They respond to
signals in dissolved
molecules in food.
• Sweet, Sour, salty, bitter
and savory (umani)
• Olfactory cells react to
chemicals in the air that
dissolve in the lining of the
nasal cavity, triggering an
impulse to the brain.
• Taste and Smell detect
chemical cues from the
environment.
The Nervous System
Keep Your Cool!
What is the function of the endocrine system?
• The endocrine system controls body functions and helps
maintain homeostasis by using hormones.
• A hormone is a chemical messenger made in one cell or
tissue that causes a change in another cell or tissue
elsewhere in the body.
• Hormones are produced by endocrine glands or tissues and
travel through the bloodstream.
• A gland is a group of cells that make special chemicals
(hormones) in your body.
The Nervous System
Keep Your Cool!
How do Hormones Work?
• Travel through the blood.
• Hormones only affect specific target cells that have
a specific receptor to that hormone.
The Nervous System
The Endocrine
System
Functions of Endocrine Glands
The pituitary gland communicates with the hypothalamus to
control many body activities.
The Nervous System
The Endocrine
System
The Nervous System
The Endocrine
System
Functions of Endocrine Glands
The ovaries in females and testes in males are also endocrine glands.
Ovaries: release
the hormone
estrogen that
controls changes
in the female
body. Trigger egg
development
Testes: release
the hormone
testosterone,
which controls
changes in the
male body and
regulates sperm
production
The Nervous System
And Endocrine Systems
What glands make up the endocrine system?
• The pituitary gland (brain) secretes hormones that
control growth/sexual development and the functions of
other glands.
• The hypothalamus (brain) controls the release of
hormones from the pituitary gland.
• The pineal gland (brain)makes hormones that control
sleep, aging, reproduction, and body temperature.
• The thyroid gland controls metabolism.
• The parathyroid gland controls calcium in the blood.
• Reproductive hormones control reproduction.
• The pancreas regulates blood-sugar levels (glucose).
• Adrenal gland controls the body’s fight or flight
response in dangerous situations by increasing blood
pressure and heart rate during times of stress.
The Nervous System
Endocrine System
1) Pituitary gland
2) Thymus
3) Adrenal gland
4) Ovaries (female)
5) Pineal gland
6) Thyroid
7) Pancreas
8) Testes (male)
Gland / Function
1) Pituitary
2) Pancreas
3) Testes
4) Adrenal
5) Thyroid
6) Ovaries
7) Parathyroid
8) Pineal gland
9) Thymus
The Nervous System
Feedback
How are hormone levels controlled?
• The endocrine system helps maintain homeostasis by
increasing or decreasing hormone levels.
• The endocrine system uses a feedback mechanism to
maintain homeostasis.
• A feedback mechanism is a cycle of events in which
information from one step controls or affects a previous
step.
• In negative feedback, the effects of a hormone cause the
release of that hormone to be turned down.
• In positive feedback, the effects of a hormone stimulate the
release of more of that hormone.
The Nervous System
The Nervous System
The Nervous System
What are disorders of the
endocrine and nervous systems?
Endocrine System Disorders
• Hormone imbalances can happen when the endocrine
system makes too much or too little of a hormone.
• Type 1 diabetes is caused by a hormone imbalance.
Pancreas does not make enough insulin.
Nervous System Disorders
• Parkinson’s disease: cells that control movement are
damaged.
• Multiple sclerosis: Affects the brain’s ability to send
signals to the rest of the body.
• Spinal-cord: Blocks information to and from the brain
because impulses from the brain could not get past the
injured site.