1. Divisions of the Nervous System Describe the structures and functions of the CNS and PNS Explain what a reflex is ID 2 ways in which the NS can be injured

2. Divisions of the NS ► Central Nervous System- consists of the brain and spinal cord ► Peripheral Nervous System- all nerves outside of the CNS

3. Central Nervous System ► The control center of the body, including the brain and spinal cord ► Brain- located in the skull, controls most functions of the body ► Spinal cord- the thick column of nervous tissue that links the brain to most nerves in the PNS

4. Central Nervous System ► Three main regions of the brain that receive and process info  Cerebrum  Cerebellum  Brain Stem

5. Central Nervous System ► Cerebrum- largest part of the brain  Interprets input from senses, controls movements, and carries out complex mental processes  Divided into right and left halves  The right- sends impulses to skeletal muscle on the left side of the body  The left-sends impulses to skeletal muscle on the right side of the body

6. Central Nervous System ► Cerebrum-  The right- Creativity, artistic ability  The left- math skills, logical thinking  Certain area are associated with smell, touch, taste, hearing, and vision as shown on pg 185

7. Central Nervous System ► Cerebellum- 2 nd largest part of the brain  Coordinates actions of your muscles and helps keep balance

8. Central Nervous System ► Brain stem- btwn the cerebellum and spinal cord  Controls body’s involuntary actions

9. Central Nervous System ► Spinal cord  The link btwn your brain and the PNS  Protected by connective tissue and watery fluid

10. Peripheral Nervous System ► Consists of a network of nerves that branch from the CNS and connect to the rest of the body ► Involved in both involuntary and voluntary actions ► 43 pairs of nerves

11. Peripheral Nervous System ► How spinal nerves function  Like a two lane highway  Impulses travel both to and from the CNS  Sensory n. carry impulses from the body to the CNS  Motor n. carry impulses from CNS to body

12. Peripheral Nervous System ► Nerves of PNS are divided into 2 groups  Somatic ► Controls voluntary actions (tying your shoes)  Autonomic ► Controls involuntary actions ► Regulates contractions of smooth muscles

13. Reflexes ► An automatic response that occurs very rapidly and without conscious control ► Help protect the body

14. Reflexes ► Reflex pathway  Sometimes skeletal muscles contract with involvement of spinal cord only, not brain  Touch a sharp object- message to spinal cord, impulse moves to motor n. in arm and hand causing muscles to contract

15. Reflexes ► Signaling the brain  At the same time, nerve impulses make your arm muscles contract, other nerve impulses travel to the brain  The impulse reaches the brain, and you feel pain  By the time you feel pain, your hand is already removed

16. Nervous System Injuries ► Two ways  Concussions  Spinal cord injuries

17. Nervous System Injuries ► Concussions  A bruise-like injury of the brain  Occurs when soft tissue of the brain collides against the skull  May occur when your bump your head  Most of the time- you have a headache, injured tissue heals itself  More serious concussions- may lose consciousness, feel confused, or feel drowsy

18. Nervous System Injuries ► Spinal cord injuries  Occur when the spinal cord is cut or crushed  Axons in the injured area are damaged, impulses cannot pass through them  Usually results in paralysis (loss of movement)