Chpt 14 Lecture Notes
Chapter Emphasis
General Senses
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Visceral Sensations
Touch
Temperature
Pain
Proprioception
Special Senses
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Taste
Smell
Hearing
Equilibrium
Vision
General Senses - Cannot live without these basic senses
Sense organs are extensions of the CNS (central nervous system) that allow monitoring of outside/inside
animal
Sensory receptors (dendrites), when stimulated, generates nerve impulse that travels via CNS and
interpreted as particular sensation (pain, pleasure, hot, cold, etc)
4 General types
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2.
3.
4.
Mechanical stimulus (touch, hearing, balance)
Thermal (hot, cold)
Electromagnetic (vision)
Chemical (taste, smell)
Visceral sensations
Miscellaneous category of internal sensations (think hunger/ thirst) that makes an animal initiate a
behavior that will provide substances needed (food/water) to maintain equilibrium (homeostasis) within
the body.
Touch
Touch, pressure= tactile sensations
Temperature
Monitors body’s temperature homeostasis
Pain
Receptors called nociceptors are most common sensory receptors within body/skin, found everywhere
throughout the body (except where…?). Four processes contribute to nociception:
1. Transduction- Stimuli converts to nerve impulse from sensory nerve ending (example: Poke dog
in cephalic vein with needle to draw blood)
2. Transmission- Sensory fibers take nerve impulse to spinal cord
3. Modulation- “changing” of the sensory nerve impulse along spinal cord on the way to the brain
4. Perception- How several different areas of the brain perceive the pain impulses. This can vary
based on various things (pain impulses received while anesthetized vs. awake, acute pain vs.
chronic pain, species of animal, personality??)
Proprioception
Knowing what position your legs/body is in at all times. Helps make smooth body movements, maintain
equilibrium and compatibility with life 
Special Senses - You can live without them (but would you want to??). Includes the four
basic senses plus equilibrium
Taste (aka gustatory sense) Taste buds are chemical receptors located in the mouth, on the sides of
papillae
Smell (olfactory sense) Chemical sense similar to taste. Not as important for humans as for other
prey/predator species. Two patches of olfactory epithelium located in each nasal passage contains the
olfactory cells that send nerve impulses to the brain when stimulated by an odor molecule.
Hearing (auditory sense) Mechanical sense used to convert vibrations in the air into nerve impulses that
are interpreted as different sounds. Divided into external, middle and internal ear.
Equilibrium Mechanical sense of balance, its receptors located in the vestibule and semicircular canals
located in the inner ear. Information received by eyes and proprioceptors throughout body also affect
equilibrium.
Semicircular Canals Contains endolymph that moves hairs that generate nerve impulses that tell the
brain you are moving.
Vision Eye contains photoreceptors in the back of the eye (the retina) that send information to brain
Tapetum lucidum Reflective “eyeshine” that aids vision in low-light situations