Divisions of the Nervous System

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- 2nd 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)