The Nervous System
Warm-up:
• Tell me about your favorite memory. When in
your life did it happen? What things do you
remember about it? Why is it so meaningful to
you?
• “In some ways, the human brain resembles a computer.
But in addition to logical processing, it is capable of
complex development, learning, self-awareness, emotion,
and creativity. Every second, millions of chemical and
electrical signals pass around the brain and the body’s
intricate nerve network. But nervous tissue is delicate and
needs physical protection and a reliable blood supply. If
damaged, repair is often painstakingly slow, and nerve
degeneration is one of the least understood medical
problems.”
Nervous System
—the human body book
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Memories, thoughts, and emotions
Touch, taste, and smell
Ears, hearing, and balance
Eyes and vision
Processes that involve
your nervous system
The Nervous System
• The nervous system is the body system that carries messages to
and from the brain and spinal cord and all other parts of the
body.
• The nervous system is composed of three divisions:
• The central nervous system (CNS)
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Brain and spinal cord.
• The peripheral nervous system (PNS)
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Made up of nerves that branch out from the central nervous system to
muscles, skin, internal organs, and glands.
• The autonomic nervous system (ANS)
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It’s work is primarily “automatic”
Deals with activities such as blood pressure control and heart rate
adjustment.
The Central Nervous System
• Brain
• The brain is a mass of nerve tissue that regulates
non-conscious processes and coordinates most
voluntary movement.
• Accounts for 2% of a person’s body weight but
requires 20% of the body’s blood.
• The brain has three major parts:
• The cerebrum controls the ability to memorize, think, and
learn.
• The cerebellum controls and coordinates muscle activity.
• The brain stem controls the functions of the internal organs.
The Central Nervous System
• Spinal Cord
– The spinal cord is the column
of nerve cells that extends
downward from the brain.
– Your spinal cord carries
messages to and from your
brain and all parts of your
body.
– It is the link from your brain
to your torso, arms, and legs.
• Nerve Cells
– The nervous system is
composed of cells
called neurons.
– A neuron is a nerve
cell that is the
structural and
functional unit of the
nervous system.
The Peripheral
Nervous System
– Each neuron consists of:
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A cell body is the main body of
the neuron.
An axon is an elongated fiber
that carries impulses away from
the cell body to the dendrites of
another neuron.
Dendrites are branching fibers
that receive impulses and carry
them to the cell body.
Peripheral Nervous System
• Sensory and motor
neurons work together to
help you respond to your
environment.
• Sensory neurons carry
impulses from the sense organs
to the spinal cord and brain.
• Motor neurons carry
responding impulses to
muscles and glands from the
brain and spinal cord.
• http://www.youtube.com/wat
ch?v=4eZRkOIj63A
• Has the task of maintaining constant conditions of the
body, or homeostasis.
• It has two divisions that produce contrasting responses:
• Sympathetic division: prepares the body for action and
stress.
• Pupil dilate
• Increases heart rate
• Parasympathetic division: restores normal function to
conserve energy.
• Pupils contract
• Decrease heart rate
Autonomic Nervous System
Caring for Your Nervous System
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Eat a well-balanced diet
Exercise regularly
Get enough sleep
Wear protective gear
Wear a safety belt
Check depth of water before diving.
Drugs and alcohol can permanently damage nerve cells,
so avoid using them.
Problems of the Nervous System
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Headaches/Migraines
Head injuries—such as concussions
Spinal injuries
Stroke
Dementia or Alzheimer’s disease
Meningitis
• An inflammation of the spinal and cranial meninges caused
by bacterial or viral infection.
• http://youtu.be/_AsvnNrGvOc
• http://abcnews.go.com/GMA/OnCall/video/teens-strugglebacterial-meningitis-11542169
• “Few body parts renew as rapidly as the skin. Every
month the outer layer of epidermis is completely
replaced, at a rate of 30,000 flake-like dead cells every
minute. The hair and nails are likewise self-reinstating
and self-repairing. Skin reflects aspects of general health,
especially diet and lifestyle. Its exposed and dynamic
nature can bring problems such as rashes, lesions, sores
and eczema. Skin growths may follow exposure to
harmful chemicals or cancer-triggering ultraviolet and
other hazardous radiation.”
Integumentary System
—the human body book
Integumentary System
• The integumentary system is the body system that
covers and protects the body and consists of skin,
glands associated with the skin, hair, and nails.
• The skin is the largest organ in the body and contains
nerve cells that help you detect pain, pressure, touch,
heat, and cold.
• Skin serves as a protective layer that helps prevent
injury, keeps microorganisms from entering the body,
and helps maintain a healthful body temperature.
• It also helps protect you from ultraviolet radiation
because of the presence of melanin, which is a pigment
that gives the skin its color.
Skin
– Skin is made up of two
layers, the epidermis and
the dermis.
• The epidermis is the outer
layer of skin cells.
• New skin cells are produced
in the deepest layer
of the epidermis.
• The dermis is a thick layer of
cells below the epidermis that
contains sweat glands, hair
follicles, sebaceous (oil)
glands, blood vessels, and
nerves
Glands
– A sweat gland is a gland that aids the body in
getting rid of wastes, such as salt, and also helps
cool the body.
– A sebaceous gland is a small oil-producing gland
that helps protect the skin. Sebum is the oil
produced by sebaceous glands.
– The subcutaneous layer is a layer of fatty tissue
located below the dermis.
Skin Conditions
– Warts/Moles/Cysts
– Acne
– is a skin disorder in which hair follicles or pores in the
skin become plugged with sebum.
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Ring worm
Psoriasis
Eczema
Sunburns
Hair and Nails
• Nails are made up of dead cells and keratin, which is a tough
protein.
• Hair is a threadlike structure consisting of dead cells filled
with keratin.
• Each hair grows from a follicle, which is a depression on the
surface of the dermis that contains nutrients a hair needs to
grow.
Keeping the Integumentary System Healthy
• Wear sunscreen!!
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SPF of at least 30
UV-A and UV-B protection
Apply 30 minutes before sun exposure
Reapply every 2 hours
Do not rely on just sunscreen
• Examine skin monthly for any changes in
moles, warts, or freckles.
• Follow directions when using makeup.
• Shower or bathe each day.
• Eat foods containing vitamin A.
• Seek proper medical care for skin rashes.
• Wash hair and body regularly.