1. WARM UP 3/17 1. What is a Schwann cell? 2. What are interneurons? 3. What are the 2 divisions of the autonomic? 4. What are the 3 meninges in order? 5. What is the sympathetic system? 6. Name 3 things that the sympathetic does?

2. NOTES CH 10: 3/17 SPINAL CORD

3. FUNCTION 1. Brings messages to and from the brain 2. Reflex center

4. STRUCTURE Approx. 17” long From brain base to 1 st lumbar vertebrae Size of thumb

5. Center looks like an “H” - gray matter – cell bodies - white matter – myelinated axon (more white mater on top – all axons from body go through there)

6. TRACTS = bundles of nerves 1. ASCENDING TRACTS – carry impulses up the sp cord (afferent neurons) 2. DESCENDING TRACTS – carry impulses down the sp cord (efferent neurons)

8. A pair of SPINAL NERVES exit from each segment of the sp cord 31 pairs total: 8 prs – cervical nerves 12 prs – thoracic 5 prs – lumbar 5 prs – sacral 1 coccygeal

9. EXTRA CREDIT OPP. There are 31 pairs of spinal nerves…… If you can memorize all 31 in 2 minutes, then you get an ec slip….BUT If you don’t get them all, then you have to lose 5 participation points from your grade. WHO WANTS TO PLAY?????????????

10. SPINAL CORD NERVE NAMES C1, C2, C3, C4, C5, C6, C7, C8 T1, T2, T3….. T12 1L, 2L …5L 1S, 2S …. 5 S coccygeal

11. PARALYSIS – if sp cord cut or crushed, loss of senses and motor of area below it PARAPLEGIC – legs paralyzed QUADRAPLEGIC – arms and legs paralyzed

12. LABELING 1. Dura mater 2. Subdural space 3. Arachnoid 4. Pia mater 5. Skin 6. Periosteum 7. Bone

13. 8. Dura mater 9. Arachnoid 10. Pia mater 11. Spinal cord 12. Dorsal root 13. Ventral root ** Central canal

14. 14. Dura mater 15. Arachnoid 16. Pia mater 17. Spinal nerves 18. vertebrae (bone)

15. On labeling sheet HOW A MESSAGE TRAVELS THROUGH THE BODY

16. 1. Stimulus detected by receptors 2. Impulse travels through afferent neurons to spinal cord (* see steps through a neuron) 3. Ascending tract up spinal cord to brain 4. Brain interprets message 5. MESSAGE CAN STOP HERE OR CAUSE A REACTION

17. 6. Brain sends response 7. Descending tract down spinal cord from the brain 8. Impulse travels through efferent neurons to muscle or gland 9. Body response