1. THE SENSES Chapter 9

2. Sense Organs  Microscopic receptors widely distributed throughout the body in the skin, muscles, tendons, joints, and other internal organs SSmell TTaste VVision HHearing EEquilibrium GGrouped into localized areas or into complex organs GeneralSpecial

3. Common Characteristics of Sense Organs SSense or detect a stimulus or a change in/of the stimulus CChange stimulus into an electrical signal: nerve impulse NNerve impulse travels to brain where it can be perceived

4. General Sense Organs  Distribution is widespread  Single-cell receptors are common  Most are in the skin

5. Free Nerve Endings  in the skin and mucosa  pain, crude touch, temp, itch, and tickle WhereWhat

6. Meissner’s Corpuscles  skin (in the papillae of the dermis) and fingertips and lips  fine touch and low frequency vibration WhereWhat

7. Ruffini’s Corpuscles  Skin (dermal layer) and subcutaneous tissue of fingers  touch and pressure WhereWhat

8. Pacinian Corpuscles  subcutaneous, submucous, and subserous tissues  around joints in mammary glands and external genitals of both sexes  pressure and high frequency vibration WhereWhat

9. Krause’s End-Bulbs  skin (dermal layer), subcutaneous tissue, mucosa of lips and eyelids, and external genitals  touch and possibly cold WhereWhat

10. Golgi Tendon Receptors (proprioceptors)  near junction of tendons and muscles  Deep within skeletal muscle tissue  sense muscle tension  cause muscle to relax (protective) WhereWhat

11. Muscle Spindles  skeletal muscles  sense of muscle length  cause muscle to contract WhereWhat