Do Now

1. Do Now • Get into a group of 3 with the people who have the same Case # as you on their Do Now paper. • Read the article and summarize it as a group. Choose someone to speak for your group!

2. Objectives • Identify and explain the different types of sensory receptors. • Explain referred and phantom pain. • Compare and contrast acute and chronic pain.

3. Special Senses 10.1-10.4

4. Phantom pain • The sensation of pain in a limb that has been amputated. • Causes aren’t completely understood • damaged nerve endings, scar tissue at the site of the amputation and the physical memory of pre-amputation pain in the affected area http://www.youtube.com/watch?v=YL_6OMPywnQ

5. Do Now • What is phantom pain? • What causes it? • What is mirror therapy? • How else could someone alleviate this pain?

6. Objectives • Identify and explain the different types of sensory receptors. • Explain referred and phantom pain. • Compare and contrast acute and chronic pain.

7. Phantom Pain • http://www.youtube.com/watch?v=hlQZmNlPdHQ

8. Receptors & Sensations Sensation • formed based on the sensory input from receptors • how brain interprets it • Projection • Brain sends the sensation back to its point of origin • person can pinpoint the area of stimulation

9. Receptive fields • Remember the 2 point discrimination in the lab? • Which part of your body had a larger receptive field?

10. Sensory adaptation • Before reading this sentence, could you feel your clothes on your skin? • The ability to ignore unimportant stimuli is called sensory adaptation.

11. Receptor categories • Somatic senses • touch, pressure, pain • Specialized senses • smell, taste, hearing, equilibrium, vision

12. Somatic receptors • Chemoreceptors • Thermoreceptors • Photoreceptors • Mechanoreceptors • Pain receptors (Nociceptors)

13. chemoreceptors • respond to changes in chemical concentrations • Ex: Monitor CO2 levels in blood and pH

14. Thermoreceptors • Respond to changes in temperature

15. Thermoreceptor activity • Place your pointer finger on your right hand in cold water and the same finger on your left hand in warm water. • Leave them in there for 1 minute • Now place them both in the room temperature water. • 

16. Photoreceptors • Responds to light • Rods- respond to light • Cones- respond to colors

17. Photoreceptor activity • Hold the ends of a pencil, one in each hand. Hold them horizontally facing each other at arms-length from your body. • 2. With one eye closed, try to touch the end of the pencils together. • 3. Now try with two eyes. • What did you experience?

18. mechanoreceptors Free nerve endings • common in epithelial tissues • simplest receptors • sense itching Meissner’s corpuscles • abundant in hairless portions of skin; lips • detect fine touch; distinguish between two points on the skin Pacinian corpuscles • common in deeper subcutaneous tissues, tendons, and ligaments • detect heavy pressure and vibrations

19. Pain receptors • “Nociceptors”- • found on free nerve endings • Respond to tissue damage Pain receptor clip: http://www.nlm.nih.gov/medlineplus/ency/anatomyvideos/000054.htm

20. Acute vs. chronic pain • Acute pain fibers: • Relatively thin, myelinated • Rapid impulse conduction, causing sharp pain • Chronic pain fibers: • Thin, unmyelinated • Conduct impulses slowly, produce a dull aching sensation

21. Referred pain • may occur due to sensory impulses from two regions following a common nerve pathway to brain • Ex: • Someone experiencing a heart attack may feel pain in their left shoulder

22. Review • What receptors detect deep pressure? • What is the difference between acute and chronic pain? • Where do you have the most receptive fields? **Monday- bring your books and notes to class! We are going to start reviewing for midterms.