1. Your Nervous System

2. What does my nervous system do?!
It receives information about what is going on inside & outside of your body
Then, it processes the information & forms a response to it

3. Neurons Neurons- basic units of the nervous system
Neurons carry impulses, or messages, from one part of your body to another
There are three types of neurons:
Sensory
Motor
Interneurons

4. Types of Neurons
Sensory= carry information about your external & internal environment
Motor= send nerve impulses to muscles & glands
Interneurons= located only in brain & spinal cord; pass impulses from one neuron to another

5. Telephone Example…
When your phone rings, SENSORY neurons carry the information about the noise to your brain.
The INTERNEURONS receive messages from your sensory neurons & your brain determines that the noise is a phone.
Finally, your MOTOR neurons signal for your muscles to pick up the phone.
All of this happens in a matter of seconds!!!

6. Neuron Structure Dendrite= carries nerve impulses to cell body
Cell body= controls cell’s basic functions
Axon= impulses travel along to other cells
Myelin Sheath= cover axons to increase the speed of an impulse
Synapse= junction between an axon & another cell

7. Nervous System Your nervous system consists of two major systems:
Central Nervous System (CNS)
Peripheral Nervous System (PNS)

8. Central Nervous System
The CNS is the control center of the body
It includes the brain & spinal cord

9. The Brain- CNS Weighs about 3 pounds
Make up of about 100 billion neurons
Protected inside skull by layers of membrane & fluid

10. The Spinal Cord- CNS
Thick column of nerve tissue that links the brain to most of the nerves in the PNS
Vertebrae protect spinal cord

11. Peripheral Nervous System
The PNS includes the network of nerves that link the rest of your body to your brain & spinal cord
Two divisions:
Sensory
Motor

12. Sensory Division- PNS
Some nerves carry information about your outside environment from your eyes, ears, nose & other sense organs
Other nerves carry information about internal body conditions such as blood pressure & heart rate

13. Motor Division- PNS
Once the central nervous system has processed the information from the sensory nerves, the motor division carries the responses back to your muscles & glands

14. Watch your nervous system in action!!
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15. Avoid head injuries!!
Concussion= bruise-like injury to the head; occurs when brain tissue hits skull
Coma= prolonged period of deep unconsciousness
Wear a helmet!
Wear your seat belt!

16. Avoid spinal cord injuries!
Paralysis= the loss of the ability to move and feel some part of the body

17. Meningitis
Nervous system infections are rare, but when they do occur they are serious
Meningitis causes inflammation of the membranes surrounding the brain & spinal cord
Symptoms are similar to the flu, but you’ll also have a very bad headache & stiff neck

18. Epilepsy
Seizure= brain experiences uncontrollable nerve impulses under certain circumstances
Causes include genetics, problems during prenatal development, and head injuries
Medication can reduce seizures in most people with epilepsy
Anyone can experience a seizure due to an injury or a bad reaction to medication

19. Headaches Most common problem of the nervous system
Avoiding triggers, proper diet, exercise & sleep can help prevent headaches
Tension headaches- caused by physical or emotional stress
Migraines- severe & long-lasting
Sensitivity to light; nausea
Cause not clear