1. Sponge: Set up Cornell Notes on pg. 45 Topic: 12.2 Touch: Pain Essential Question: 1. How do viscera (internal organs) respond differently to pain than surface tissues do? 2. What is referred pain? 2.1 Atoms, Ions, and Molecules 12.2 Touch: Pain Please turn in Lab 30 to printer

2. 2 Sense of Pain PAIN or NOCICEPTORS are widely distributed throughout skin and internal tissues almost every surface and organ has them…. EXCEPT the nervous tissue of the brain lacks pain receptors

3. 3 Provides protection as they are stimulated by tissue damage pain is supposed to be unpleasant so you remove source of stimulation caused by chemical or mechanical forces, and extremes in temperature Why do we need to experience pain? What is its major function?

4. 4 Injury is a major cause, but pain may also arise from an illness It may accompany a psychological condition, such as depression What types of events can be the cause of pain?

5. 5 Visceral Pain (Internal Organs) pain receptors are the only receptors in viscera (internal organs) whose stimulation produces sensations not well localized- not easy to identify Ex: damage to intestinal tissue during surgery may not elicit any pain, even in someone conscious when subjected to widespread stimulation, a strong pain sensation follows Ex: when intestinal walls undergo spasms, a strong pain sensation may follow (due to mechanoreceptors)

6. 6 Referred Pain Referred pain may feel as if coming from some other part of the body Ex: Before a heart attack the person may feel strong pain in their left arm/shoulder region

7. 7

8. 8 Pain threshold- The point at which an individual perceives a stimulus as painful Not a lot of difference between people

9. 9 Pain tolerance- The LENGTH of time an individual can endure pain before responding noticeably A LOT of variation between people

10. 10 Acute vs. Chronic Pain Acute pain associated with sharp pain pain stops when pain producing stimulus stops OR when injury heals can pinpoint where pain occurs EX: A pinch sunburn broken bone pulled muscle Chronic pain associated with dull, aching pain persists after injury heals difficult to pinpoint- stimulus may be unknown EX: Arthritis, cancer, depression Pg. 44

11. 11 Pain receptors adapt VERY LITTLE Once a pain receptor is activated, even by a single stimulus, it may continue to send impulse into the CNS for some time What is adaptation?

12. 12 Regulation of Pain Impulses Thalamus : allows person to be aware of pain Cerebral Cortex: judges intensity of pain locates source of pain produces emotional and motor responses to pain Pg. 45

13. 13 Regulation of Pain Impulses Pain Inhibiting Substances Serotonin Stimulates the release of enkephalins-suppresses pain, relieving strong pain sensations (like morphine) Endorphins Released in response to extreme pain provide natural pain control much like morphine

14. Suppressing Pain: The Brain’s Emergency Response (8m) 14

15. 15 Inability to Feel Pain Hereditary Sensory and Autonomic Neuropathies (HSANs) The inability to feel sensation, and therefore pain 5 different types People with HSANs rarely survive beyond their 20s Ex: Babies loose teeth from chewing toys Cuts and scrapes won’t heal Break a bone and keep moving it- playing- etc

16. Hidden Curse: The Inability to Feel Pain (2m) 16

17. 12-Year Old Girl Cannot Feel Pain Video 17

18. 18 Summary of Receptors of the General Senses