Chapter 6

1. Chapter 6 Section 4: Other Senses

2. Taste: Savory Sensations • Taste occurs because chemicals stimulate thousands of receptors in the mouth, primarily on the tongue, but also in the throat, cheeks, & roof of mouth

3. Papillae: Knoblike elevations on the tongue, containing the taste buds

4. Actual receptors for taste are inside the taste buds • Cells send tiny fibers out through an opening in the bud • Receptor cells are replaced by new cells every ten days • After 40, total number of taste buds declines

5. Bitterness & sourness help us identify foods that are rancid or poisonous • Sweetness helps us identify foods that are healthful or rich in calories • Salt is necessary for all bodily functions

6. Basic tastes can be perceived at any spot on the tongue • Center has no taste buds • Taste differences are genetic, a matter of culture & learning • Attractiveness of a food can also be affected by its color, temperature, texture, & odor

7. Smell: The Sense of Scents • Smell or olfaction

8. Airborne chemical molecules enter the nose & circulate through the nasal cavity. • Vapors can also enter through the mouth & pass into nasal cavity.

9. Sniff out dangers by smelling smoke, food spoilage, & poisonous gases • Loss can be caused by infection, disease, injury, or smoking

10. Red bars show the people who could identify a substance dropped on the tongue when they were able to smell it • Blue bars show the people who could identify the substance when they were not able to smell it

11. Senses of the Skin • Protects our innards, helps identify objects, establish intimacy with others, gives us a sense of ourselves as a distinct from the environment • Basic senses- touch/pressure, warmth, cold, & pain • Tickle, itch, & burning

12. The Mystery of Pain • When the stimulus producing it is removed, the sensation may continue, sometimes for years • Chronic pain disrupts lives, puts stress on the body, & causes depression, & despair

13. The Gate Control Theory of Pain • Experience of pain depends (in part) on whether the pain impulse gets past neurological “gate” in the spinal cord & thus reaches the brain.

14. Brain influences the gate • Thoughts & feelings can influence our reactions to pain

15. Updating the Gate Control Theory • Doesn’t explain phantom pain • Brain not only responds to incoming signals from sensory nerves but is also capable of generating pain entirely on its own • A network of neurons in the brain gives us a sense of our own bodies & body parts

16. Neuromatrix Theory of Pain • Theory that the matrix of neurons in the brain is capable of generating pain (& other sensations) in the absence of signals from sensory nerves

17. The Environment Within • Kinesthesis: The sense of body position and movement of body parts • Information provided by pain & pressure receptors located in muscles, joints, & tendons

18. Equilibrium: The sense of balance • Gives us information about our bodies as a whole • Relies on three semicircular canals in the inner ear • Tubes are filled with fluid that moves & presses on hair like receptors whenever the head rotates

19. Receptors intake messages that travel through a part of the auditory nerve not involved in hearing