The Senses of the Nervous System

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The Senses of the Nervous System

• There are five general categories of sensory
  receptors pain receptors, thermoreceptors,
  mechanoreceptors, chemoreceptors, and
  photoreceptors.

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The Eye

• Pupil - small opening in the middle of the iris
  through which light enters the eye
• Lens - transparent object behind the iris that
  changes shape to help adjust the eyes focus to
  see near or distant objects
• Retina - innermost layer of the eye
• Cornea tough, clear covering that protects the
  eye and allows light to pass through
• Humor fluids that maintain the shape of the eye
• Iris colored part of the eye that controls how
  much light enters
• Rod - photoreceptor in eye that is extremely
  sensitive to light
• Cones - in the retina of the eye, a photoreceptor
  that responds to light of different colors,
  producing color vision

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Eye
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The Ear (Hearing and Balance)

• Hearing
• Auditory Canal ear canal, where sound enters
• Tympanum Ear Drum, vibrates as sound wave hit
  it
• Cochlea - fluid-filled part of the inner ear
  sends nerve impulses to the brain through the
  cochlear nerve
• Ear bones
• Hammer
• Anvil
• Stirrup
• Eustachian tube equalizes pressure between
  environment and inner ear
• Oval window sends waves of pressure to cochlea
• Balance
• semicircular canal - one of three structures
  within the inner ear that help an organism
  maintain balance (oriented perpendicular to each
  other)

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Ear
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Semicircular Canals
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Smell and Taste

• Chemoreceptors receptors which sense different
  Chemicals
• Taste and smell are linked closely together
• Hold your Nose
• taste bud - sense organ that detects the flavor
  of a substance

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Touch Related Senses

• Touch Mechanoreceptors
• Temperature Thermoreceptors
• Pain Pain Receptors

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Questions

1. Name the five types of sensory receptors and list
   where they are found in the body.
2. Identify the parts of the eye and the function of
   each part.
3. What parts of the ear are responsible for
   hearing? For balance?
4. Explain why you cant taste food when you have
   a bad cold.
5. Why do you feel dizzy after spinning around? How
   can a dancer or ice skater do lengthy spins?