Chapter 6

Chapter 6. Section 4: Other Senses. 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. Papillae: Knoblike elevations on the tongue, containing the taste buds.

Chapter 6Section 4: Other SensesTaste: 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

Papillae: Knoblike elevations on the tongue, containing the taste budsActual 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

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

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

Smell: The Sense of Scents

Smell or olfaction

Airborne chemical molecules enter the nose & circulate through the nasal cavity.

Vapors can also enter through the mouth & pass into nasal cavity.

Sniff out dangers by smelling smoke, food spoilage, & poisonous gases

Loss can be caused by infection, disease, injury, or smoking

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

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

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

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.

Brain influences the gate

Thoughts & feelings can influence our reactions to pain

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

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

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

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

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