Other Senses: Outline

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Other Senses Outline

• Balance (Vestibular System)
• Taste
• Smell
• Touch

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Balance

• Three sources of balance
• Vision
• Stretch receptors in muscles
• Vestibular system
• Worst case scenario
• getting up in the middle of the night (no
  vision), from your futon (poor info from stretch
  receptors), in a yacht (poor vestibular info).

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Vestibular System Functions

• Balance
• Coordinates head body movements
• Keep eyes fixed when head moves
• Semicircular Canals
• Rotations (3-D)
• Dizziness is triggered
• By rotation (kids)
• By hot water in ear stimulates movement of fluid
  in vestibular chambers
• vertigo

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• Vestibular Sacs Function
• linear accelerations
• static head positions

From inner ear, output goes to Medulla from
there to - Spinal Cord, - Oculomotor Nerve,
- Cortex, - Cerebellum
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Taste

• Flavor is inferred from
• Taste (5)
• Smell (500-10,000 odors), and
• Tactile information, pain receptors (chili
  peppers)
• Supertasters
• Genetic differences in receptors
• Increased sensitivity to bitterness, sweet

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Taste Receptors

• Papillae

• Bitter
• Sweet
• Sour
• Saltiness Na channel
• Umami
• elicited by the amino acid glutamate found in
  proteins (meat, fish, beans, ketchup)
• MSG (monosodium glutamate)

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Taste Pathway

• Orbitofrontal cortex (S2)
• Amygdala
• Post central gyrus and Insula (S1)
• Thalamus
• Medulla
• Cranial nerves

Amygdala OFC are important for valence,
reinforcement
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Olfactory System

• The primary mode of communication for most
  animals
• Critical for survival
• eating
• toxic substances often smell/taste bad good
  things smell good
• reproduction
• mating partners
• aggression in rivals
• location of predators and prey

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Olfactory Anatomy

• Olfactory tract projects to
• amygdala,
• hippocampus
• hypothalamus
• Insula

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Pheromones

• Airborne molecules that affect behavior
• Especially involved in reproduction
• VNO- Vomeronasal Organ
• Physically distinct
• evolved separately
• Projects to Limbic areas

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• Somatosenses
• The stimuli
• The cutaneous senses respond to several different
  types of stimuli pressure, vibration, heating,
  cooling, and events that cause tissue damage (and
  hence pain).
• Some receptors report changes in muscle length to
  the brain providing our sense of kinethesia.
• Additional receptors provide information about
  the internal organs such as the linings of
  muscles and the gastrointestinal system.

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• Somatosenses
• Anatomy of the Skin and its Receptive Organs
• Cuntaneous sense
• One of the somatosenses includes sensitivity to
  stimuli that involve the skin.
• Kinesthesia
• Perception of the bodys own movements.
• Organic sense
• A sense modality that arises from receptors
  located within the inner organs of the body.

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