Chapter 13
Your Body Systems
Lesson 2
Your Nervous System
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Building Vocabulary
nervous system
The body’s message and control center
brain
The command center, or coordinator, of the nervous
system
neurons
Cells that make up the nervous system
central nervous
system
The brain and the spinal cord
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Building Vocabulary
peripheral nervous
system
The nerves that connect the central nervous
system to all parts of the body
spinal cord
A long bundle of neurons that sends messages to
and from the brain and all parts of the body
somatic system
The part of the nervous system that deals with
actions that you control
autonomic system
The part of the nervous system that deals with
actions you do not usually control
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Parts of the Nervous System
Your nervous system carries messages back and forth between your
brain and the rest of your body. The nervous system gathers,
processes, and responds to information received by the brain.
New Vocabulary
nervous system The body’s message and control center
New Vocabulary
brain The command center, or coordinator, of the nervous system
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Parts of the Nervous System
The nervous system
• controls all body processes, such as digestion, breathing, and
blood flow through the body.
• processes your physical and emotional feelings and reactions to
stimuli.
• receives messages from your five senses—vision, hearing, smell,
taste, and touch.
• is made of neurons.
New Vocabulary
neurons Cells that make up the nervous system
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
The Central Nervous System
Your nervous system has two parts—the central nervous system
(CNS) and the peripheral nervous system (PNS).
New Vocabulary
central nervous system (CNS) The brain and the spinal cord
New Vocabulary
peripheral nervous system (PNS) The nerves that connect the central nervous system
to all parts of the body
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Parts of the Nervous System
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
The Central Nervous System
• The cerebrum controls memory, language, and thoughts.
• The cerebellum controls voluntary muscle movement. It also
stores muscle movements you have learned, such as tying
your shoes or riding a bike.
• The brain stem controls involuntary muscle movement.
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
The Central Nervous System
Your spinal cord is also part of your central nervous system. The
neurons in the spinal cord reach out to other parts of the body. The
brain responds to information through the neurons in the spinal
cord.
New Vocabulary
spinal cord A long bundle of neurons that sends messages to and from the brain and all
parts of the body
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
The Peripheral Nervous System
The peripheral nervous system has two parts. The somatic system
handles movements you control. The autonomic system
handles those movements you do not control.
New Vocabulary
somatic system The part of the nervous system that deals with actions that you control
New Vocabulary
autonomic system The part of the nervous system that deals with actions you do not
usually control
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Problems Affecting the Nervous System
One of the most common causes of damage is injury to the head,
neck, or back. Since the brain is your control center, an injury can
cause memory loss, brain damage, or the loss of some physical
abilities.
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Problems Affecting the Nervous System
Other issues that affect the nervous system include:
Multiple sclerosis, or MS, which damages the outer part of some
nerves.
Cerebral palsy, which is a disease of the nervous system that either
inherited or caused by brain damage.
Alzheimer’s disease, which most often affects older adults, harms
the brain and causes loss of memory.
Parkinson’s disease, which is a brain disorder that causes shaking
and stiffness of the arms and legs.
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Problems Affecting the Nervous System
Other issues that affect the nervous system include:
Epilepsy, which occurs when signals in the brain do not send
messages in the normal way.
Viruses, such as polio, rabies, meningitis, encephalitis, and West
Nile virus.
Alcohol, which can destroy brain cells.
Other drugs, which can harm the part of the brain that helps control
your heart rate, breathing, and sleeping.
Lesson Home
LESSON 2
Your Nervous System
BIG IDEA
Your nervous system controls and sends messages throughout your body.
Caring for Your Nervous System
• Make healthful food choices, drink plenty of water, and get plenty
of sleep.
• Stay physically fit and maintain a healthy weight.
• Protect yourself against insects and avoid animals that may carry
disease.
• Wash your hands thoroughly and often.
• Use safety equipment when you participate in physical activities.
• Wear a safety helmet when riding a bike or skating.
• Wear a seat belt when riding in a car.
• Do not to use alcohol or other drugs.
Lesson Home