Sensation Taste, Smell and Touch

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Sensation Taste, Smell and Touch
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Objectives

• Discuss the role of the kinesthetic and
  vestibular senses in body position, balance, and
  equilibrium.
• Discuss the role played by the skin in the
  sensation of touch, including the types and
  distribution of sensory receptors in the skin.
• Explain how taste sensations are produced and
  identify the basic taste categories.
• Define pheromones, and discuss the research
  evidence supporting the notion that human
  pheromones exist.
• Describe the process of olfaction, including the
  transmission of olfactory information to the
  brain.

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Sensation

• The process of detecting a physical stimulus,
  such as light, sound, heat, pressure, etc,

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Sensory Receoptors

• Cells that specialize in each individual sense
  and respond to a specific type of stimulus.

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Transduction

• The process by which a form of physical energy is
  converted into a coded neural signal that can be
  processed by the nervous system.

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Sensory Threshold

• Our abilities to detect energy from the outside
  world is not infinite
• The point at which a stimulus is strong enough to
  be detected.

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Absolute Threshold

• The smallest possible strength of a stimulus that
  can be detected half the time.

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Gustation

• Taste is a chemical sense.
• The little bumps on our tongues are actually
  called papillae
• Inside some of these papillae are clumps of taste
  cells.
• These clumps of cells are actually the taste
  buds.

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Taste

• On average, adults have about 7,500 taste buds.
• These receptor cells are located in the tongue
  and in the mouth.
• When food dissolves on these receptors,
  TRANSDUCTION occurs
• Damaged taste receptor cells are replaced within
  a few days to 2 weeks

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Taste

• Substances dissolved by saliva activating the
  taste buds
• (cheeks, roof of mouth, throat, tongue)

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• Taste Sensations
• sweet
• sour
• salty
• bitter

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Supertasters

• People with an abundance of taste receptors
• Approximately 25 of the population

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Nontasters

• People with a minimum of taste receptors
• Taste with less intensity than the rest of the
  population
• Approximately 25 of the population

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Other Senses Smell

• Module 9 Sensation

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Other Senses
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Olfaction

• Olfactory cells in the upper nasal passages
  detect molecules in the air.
• Taste and smell interact to produce flavor.

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Olfaction

• Smell is a chemical sense.
• Olfactory receptors/cells in the upper nasal
  passages detect molecules in the air.
• Taste and smell interact to produce flavor.

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Olfactory Cells

• The chemical receptor cells for smell
• Located in the nasal passages

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Smell
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Smell
Smell
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Do Pheromones Influence Human Behavior?

• Please read the article on page 100 in your
  textbook and record your answer. Remember to
  explain your reasoning.

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Other Senses Touch
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Touch

• Touch receptors are on the skin
• Four basic skin senses are
• Pain, warmth, cold, and pressure
• All skin sensations are a combination of these
  four basic senses

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Sensitivity to Pain

• Most Sensitive
• Back of knees
• Neck region
• Bend of elbow

• Least Sensitive
• Tip of the Nose
• Sole of foot
• Ball of thumb

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• Pain messages travel on one set of nerve fibers
  containing pain gates.
• The gates are open when pain is felt.
• Other sensory messages go through another set of
  fibers.
• The non-pain fibers can close the pain gates to
  stop the sense of pain.

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Gate-control Theory of Pain

• Pain is a product of both physiological and
  psychological factors.
• The gates are open when pain is felt.

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The last sense.
Maybe.
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Kinesthetic Sense

• The technical name for the sense of location and
  position of body parts in relation to one
  another.
• Ones leg falling asleep is a disruption of the
  kinesthetic sense

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Proprioceptors

• Sensory receptors, located in the muscles and
  joints, that provide information about body
  position and movement.

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Vestibular Sense

• DEFINITION The technical name given to the sense
  of balance or equilibrium.

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Sources of Sensory Information

• Semicircular canals
• Vestibular sacs

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How Does It Work?

• Both structures are filled with fluid and are
  lined with tiny hairlike receptors. These
  structures shift in response to motion or changes
  in gravity.

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I Need Three Volunteers
Three Volunteers Please

• Who thinks they have a decent vestibular sense?

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Do That.
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Lets Review

• Name the senses
• How many do you have?
• Think again

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The Senses

1. Vision
2. Hearing
3. Tasting
4. Touching
5. Smelling

• Kinesthetic
• Vestibular

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Reviewing Our Objectives

• Winner gets three
• The other person gets two

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Reviewing Our Objectives

• Turn to your neighbor and describe all
  objectives.
• Use as many vocabulary terms as possible.

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• Discuss the role of the kinesthetic and
  vestibular senses in body position and balance.
• Discuss the role played by the skin in the
  sensation of touch.
• Explain how taste sensations are produced and
  identify the basic taste categories.
• Define pheromones, and discuss the research
  evidence supporting their existence.
• Describe the process of olfaction, including the
  transmission of olfactory information to the
  brain.

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The End