2. Spinal cord and Peripheral nervous system \

3. Spinal cord - Functions  Sensory and motor pathway

4. Reflex arc (spinal cord)  Reflex center –  Sensory receptor  Sensory neuron  Interneuron (association neuron)  Motor neuron (effector)  An effector organ

5. Spinal Cord Anatomy  Association neuron  Motor http://www.bayareapainmedical.com/wspin ecrd.html http://www.bayareapainmedical.com/wspin ecrd.html  Gray Matter – “butterfly” interneurons  White Matter – myelinated

6. Spinal cord Anatomy

7. Spinal Cord tracts  Sensory  1. Dorsal column 2. Spinothalamic  Ascending tracts  temperature, pressure, pain, light, touch

10. Spinal cord tracts continued Motor tracts 1. Corticospinal  Decending  Skeletal tone, voluntary muscle movement

11. Nerves attached to Sp. Cord  Dorsal Root Ganglia – bundle of sensory nerves  Ventral Root Ganglia – bundle of motor fibers

12. Peripheral Nervous system

13. Somatic Nervous System  Includes all nerves in the musculoskeletal system, sense organs  Receptor (receives impulse) to Effector (muscle fiber)

14. Autonomic Nervous System  Motor neurons that control internal organs (involuntary)  Innervate all organs  Two divisions of

15. Autonomic Nervous System  Sympathetic  “Fight or flight response”  Inhibits digestion  Pupils dilate  Accelerates heart rate  Increase breathing rate.  Parasympathetic  Normal state  Promotes digestion  Pupils constrict  Normal heartbeat  “feed and breed”

16. The Eye: Photoreceptor  Lens – refraction and focusing  Iris – controls entrance of light into eye  Pupil – window into the eye  Choroid – blood vessels, absorbs stray light

17. Eye anatomy continued  Sclera – white fiborous layer, protection  Humors –  Aqueous humor – between the cornea an lens  Viterous humor – fills large cavity, gelatinous material

18. Eye Anatomy continued  Ciliary body – holds lens in place  Retina – contains receptors  Cones – color vision  Rods – black and white vision  Optic Nerve

19. Rods and Cones Illustration

20. Eye Anatomy Continued  Optic Nerve – picks up impulse  Ciliary muscles – controls the shape of the lens  Accommodation –  Additional focusing power  Near object – ciliary muscle contracts, lens becomes round

21. Physiology of sight  Focusing – light rays bent by cornea, focus on the retina, refraction and inverted

22. Fields of VisionFields of Vision Illustration Refer to Lab on eye dissection

23. Cross section of head

24. Normal Vision 20/20  at a distance of 20 feet, you can read a certain line (labeled 20) on the chart and that your vision is normal.  20/40 -

25. Nearsightedness (myopic) Farsightedness (hyperopia)

26. Disorders of the Eye: Glaucoma – built up pressure in the eye due to lack of aqueous humor drainage

27. Vision of a person with Glaucoma

28. Cataracts- clouding of the lens