The Senses: Introduction and Receptors

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

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

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

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

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

Classification According to Location

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

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

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

Classification According to Stimulus

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

2. Thermoreceptors temperature changes

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

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

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

Classification by Structure