The Nervous System

Question???

• What to brushing your teeth, riding a bike, and solving a math problem have in common??

• ANSWER…. ___________________

ANSWER:

• They all happen from instructions from your body’s “Control Center” aka your Nervous System.

What is the Nervous System’s Job?

• It controls your thoughts and actions

Neurons

• The specialized cells that make up your nervous system.

• Also called “Nerve Cells”

• Can’t replace/repair themselves if they get damaged- different than all your other body cells!

What Does a Neuron Look Like?

Neurons

• Their job is to carry messages to and from different parts of your body.

• These messages are “weak electrical signals”

• They’re more sensitive than other cells and work very quickly!!

Parts of the Nervous System

• 3 Parts: – Brain– Spinal Cord– Many Nerves

**It is divided into 2 main sections:

-Central Nervous System- (brain and spinal cord)

-Peripheral Nervous System (nerves)

Central Nervous System

• Includes the brain and the spinal cord• The main control center, controls your body’s

actions

• Brain- gets, interprets, and sends responses• Spinal Cord- bunch of nerve tissue - organized into segments for each muscle, organ, and function/job

It Controls 2 Types of Actions:• Voluntary Actions- things you choose to

control (examples: like walking, smiling)

• Involuntary Actions- things that you can’t control (examples: breathing, heart beat)

BRAIN

• Mass or neurons that controls actions, emotions, thoughts, and memory.

• Made up of 10 BILLION neurons

• Weighs 3 lbs!!!

• It’s well protected in your skull and suspended in a fluid that’s like a shock absorber

3 Main Parts of the Brain:

• Cerebrum- senses, thinking, speech, muscle movement

• Cerebellum- balance, posture, coordination

• Brain Stem- heart beat, breathing, blood pressure, digestion

DID YOU KNOW…

• Your brain is divided into 2 halves (hemispheres)

• If you’re R Handed- your left side of the brain is more dominant

• If you’re L Handed, your right side of the brain is more dominant

(Because the R side of your Brain, controls the L side of your body!)

SPINAL CORD

• Less than 2 feet long

• Well protected by your spine

• Same diameter as your index finger

• Relays messages from your body to the brain, and from the brain to your muscles and glands.

Peripheral Nervous System

• Parts- all the nerves (that connect the brain’s signals to the rest of the body)

• The PNS is like the mailman carrying letters to and from the post office– (carries messages to and from the

brain/spinal cord)

2 Main parts of the PNS

• Somatic System- deals with actions you can control (VOLUNTARY)

• Autonomic System- deals with actions you can’t control (auto) (INVOLUNTARY)

Reflexes

• Involuntary or automatic action that your body does in response to something.

• Protect your body from things that can harm it!

• Do you know any examples???

Reflex Examples:

• Coughing when something gets in your airway

• Blinking when something is in your eye to keep it out

• Pulling your hand back when you touch a hot stove to keep your from getting burned

ACTIVITY TIME!

Short Video Review

• http://faculty.washington.edu/chudler/flash/facts.html

Problems Related to the Nervous System:

• Structural Disorders:– Head or Spinal Cord Injury

• Degenerative Disorders:– Cerebral Palsy (CP)– Multiple Sclerosis (MS)

• Infections:– Polio– Rabies, – Meningitis

GROUP ACTIVITY- pg. 296 in book!

Related Problems Cont’d:

• The most common cause of damage to the Nervous System is what??? _______

• Examples: concussion, pinched nerve, etc.

• In a sporting event, someone has a head/neck/back injury. WHAT SHOULD YOU NEVER DO??!??

Let’s See What We Learned!

• Take out a piece of paper and number it 1-

1. What are the 3 main parts that make up the Nervous System?

2. The Nervous System is divided into 2 main sections. What are they?

3. The specialized cells that make up the nervous system are called _________.

4. The 3 main parts of the BRAIN, that I showed you on the diagram, are called the __________, the _________, and the ________ ________.

5. ________ is an automatic action that your body does in response to something.

6. Why do we have reflexes?

7. The Somatic System deals with actions you __________ control, while the Autonomic System deals with actions that you __________ control.

8. Most Nervous System Injuries are caused by __________.

Check Your Answers!

1. The Brain, The Spinal Cord, and Nerves

2. Central & Peripheral Nervous Systems

3. Neurons

4. Cerebellum, Cerebrum, Brain Stem

5. Reflex

6. To protect us from dangers

7. CAN, CAN’T

8. Injuries