Sponge: Set up Cornell Notes on pg. 43 Topic: 12.3 Sense of Touch: Pressure, Temperature + Pain

1. 12.3 Sense of Touch: Pressure, Temperature and Pain 2.1 Atoms, Ions, and Molecules Sponge: Set up Cornell Notes on pg. 43 Topic: 12.3 Sense of Touch: Pressure, Temperature + Pain Essential Question: How do viscera (internal organs) respond differently to pain than surface tissues do? Text: 443-447 How do viscera (internal organs) respond differently to pain than surface tissues do?

2. Objective SWU: how the receptors associated with the sense of touch react to pressure, temperature, and pain SW: identify the different types/functions of touch, pressure, and temperature senses

3. Touch and Pressure Receptors Three kinds of touch/pressure receptors: • Free nerve endings: Common in epithelial tissue • Responsible for sensation of itching Free Nerve Ending Typically related to inflammation, dryness or other damage to the skin, mucous membranes or conjunctiva of the eye.

4. Touch and Pressure Receptors Three kinds of touch/pressure receptors:#7 on LAB 30 2. Tactile (Meissner’s) corpuscles: Abundant in the hairless portions of the skin • Lips, fingertips, palms, soles, nipples, and external genital organs • Provide fine touch, such as distinguishing two points on the skin, and to judge texture Free Nerve Ending

5. Touch and Pressure Receptors Three kinds of touch and pressure receptors: #8 on LAB 30 3. Lamellated (Pacinian) corpuscles: Common in the deeper dermal tissues of hands, feet, penis, clitoris, urethra, breasts • Heavy pressure and stretch stimulate them • Detect vibrations in tissues Free Nerve Ending

6. #9-10 on LAB 30 Temperature Receptors Two kinds of thermoreceptors: • Warm receptors: • Most sensitive above 77°-112 °F • Unresponsive above 113° F ---Pain receptors activated producing a burning sensation 2. Cold receptors: • Most sensitive between 50-68° F • Below 50 ° F --Pain receptors are stimulated producing a freezing sensation WARM

7. Temperature Receptors Sensory Adaptation:#6 on LAB 30 Warm and cold receptors adapt quickly • Within about a minute of stimulation the sensation of warm or cold begins to fade • Ex: jumping into a cold swimming pool or hot tub

8. How can something that’s hot FEEL cold?!?!?! Scenario: You stick your hand in the bathtub to check the temperature, and for a moment, your hand feels ice cold - but then only moments later, you realize that the water is actually piping hot. This phenomenon is called "paradoxical cold", and scientists still aren't exactly sure why it occurs. • Pain receptors that warn the body of high heat operate on the SAME SENSORY FIBERS  as cold receptors. • So the fiber signal could be misinterpreted as cold by the brain! Also, signals from the cold thermoceptors can travel to the brain up to 10 times faster than signals from warm receptors, which is why we might feel as if something feels very cold at first, but only a split second later, we can already feel the "real", hot temperature.

9. Sense of Pain • Nociceptors aka pain receptors arewidely distributed throughout skin and internal tissues • Almost every surface and organ has them….except…. • Hypothesize with your table which part of your body DOES NOT have nociceptors. • The nervous tissue of the brain lacks pain receptors

11. 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

13. Why do we need to experience pain? What is its major function? • Pain provides protection! Nociceptors are stimulated by tissue damage • Pain is supposed to be unpleasant so you remove the source of stimulation • Caused by chemicals, mechanical forces, and extremes in temperature

14. What types of events can be the cause of pain? • Injury is a major cause • Illness • It may accompany a psychological condition, such as depression

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

16. Visceral Pain (Internal Organs) • Visceral Pain (Internal organs): • Pain receptors are the only receptor found in internal organs • Pain is not well localized- not easy to identify spot of stimulation • When subjected to widespread stimulation, a strong pain sensation follows—i.e. cramps • When intestinal walls undergo spasms, a strong pain sensation may follow Damage to intestinal tissue during surgery may not elicit any pain, even in someone conscious

17. #5 on LAB 30 Referred Pain • Referred pain is when pain may feel as if coming from some other part of the body than the actual affected organ • Ex: Before a heart attack the person may feel strong pain in their left arm/shoulder region

19. Remember sensory adaptation? From your own experience, how well do you think nociceptors adapt? • 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

20. Pain threshold- The point at which an individual perceives a stimulus as painful • How do you think the pain threshold varies from person to person? • Not a lot of difference between people

21. Pain tolerance- The LENGTH of time an individual can endure pain before responding noticeably • How do you think the pain TOLERANCE varies from person to person? • A LOT of variation between people

22. Regulation of Pain Impulses • Pain Relieving Substances: • Serotonin: stimulates the release of enkephalins-which suppresses pain, relieving strong pain sensations (like morphine) • Endorphins: are released in response to extreme pain • Provide natural pain control much like morphine

23. P. 42 Homework • Pain Article– Acute and Chronic Pain • Read/Highlight/Answer ?s Generally, pain is considered chronic when symptoms extend beyond the expected period of healing. There is no longer tissue damage. 

24. Inability to Feel Pain • Hereditary Sensory and Autonomic Neuropathies (HSANs) is the inability to feel sensation, and therefore pain • 5 different types

25. Inability to Feel Pain "Anhidrosis" means the body does not sweat “Congenital" indicates that the condition is present from birth • HSANs IV- aka Congenital insensitivity to pain with anhidrosis (CIPA): • Extremely rare  • Inherited disorder of the nervous system  • Prevents the sensation of pain, heat, cold, or any real nerve-related sensations • Including feeling the need to urinate • Person can still feel pressure • Many people with CIPA do not live past their 20s • Exs: • Babies loose teeth from chewing toys • Cuts and scrapes won’t heal • Break a bone and keep moving it- playing-

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

27. Rare Medical Condition—CIPA4m12s https://www.youtube.com/watch?v=n6iOUW523BE

28. Pg. 40 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 • EXs: • 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 • EXs: • Arthritis • Cancer • Depression

29. Pg. 40 Acute vs. Chronic Pain Chronic Pain Acute Pain