1. The Senses: Introduction and Receptors

2. Major Groups of Senses Special Senses
produced by highly specialized and localized sense organs
includes smell, taste, sight, hearing, and balance

3. General Senses widely distributed
includes touch, pressure, pain, temperature, vibration, itch, and proprioception (position)

4. Terms
stimulus - anything from inside or outside the body that can cause a response
sensation or perception awareness of stimuli received by sensory receptors

5. Sensory Receptors
sensory receptors are structures that are specialized to respond to changes in their environment = stimulus

6. 3 Kinds of Classification
by general location
by stimulus detected
by structure

7. Classification According to Location

8. Classification According to Location
exteroceptors
stimuli outside of body
touch, sight, sound, pressure, pain, temperature

9. 2. interceptors stimuli within the body
tells about status of internal organs
chemical changes, pressure, stretching tissue
cause pain, hunger, thirst

10. 3. proprioceptors located in skeletal muscles and joints
advise us of our movement and body position

11. Classification According to Stimulus

12. Classification According to Stimulus
Mechanoreceptors
mechanical forces
ex: inner ear - sound, pressure - touch of skin, stretch receptors in bladder, lungs, and blood vessels

13. 2. Thermoreceptors
temperature changes

14. 3. Photoreceptors retina of eye (rods and cones)
stimulated by light energy

15. 4. Chemoreceptors chemicals in solutions taste buds
olfactory - odor molecules
interceptors responding to changes in O2, CO2, and ions

16. 5. Nociceptors nocere = to injure
respond selectively to potentially damaging stimuli
pain - includes all stimulus when in excess

17. Classification by Structure