1. Dermis and Specialized Structures, Sensation

2. Dermis Collagen, elastin fibers– scatteredCollagen, elastin fibers– scattered

3. Dermal-epidermal junction Dermal papillae: parallel rows of peg-like projectionsDermal papillae: parallel rows of peg-like projections –High level of variation  Fingerprints

4. Dermis Specialized structures:Specialized structures: –Hair follicle: cells of the epidermis extend into the dermis forming a small tube –Hair bulb: base of the follicle –Hair papilla: cluster of cells (live); nourished by BV’s –Root: part of hair hidden in follicle –Shaft: visible part of hair

7. Dermis Specialized Structures (continued)Specialized Structures (continued) –Arrector pili: tiny, smooth muscle attached to base of dermal papillae & side of hair follicle Contraction  goosebumpsContraction  goosebumps

8. Specialized Structures of the Dermis Sebaceous GlandsSebaceous Glands –Secrete oil (sebum) for hair/skin –Ducts open into hair follicles –Accumulated sebum enlarges ducts  white heads –Darkened sebum  black head

10. Specialized Structures of Dermis Sudoriferous GlandsSudoriferous Glands –Eccrine Glands WidespreadWidespread Watery FluidWatery Fluid ThermoregulationThermoregulation –Apocrine Glands Armpits/GenitalsArmpits/Genitals Thick/milky fluidThick/milky fluid Produce odor whenProduce odor when exposed to bacteria

13. Pacinian Corpuscle Deep in the dermisDeep in the dermis Deep pressure touchDeep pressure touch High frequency vibrationHigh frequency vibration

14. Meissner’s Corpuscle Superficial – within dermal papillaeSuperficial – within dermal papillae Light touchLight touch

15. Krause’s end bulb Touch/ low frequency vibrationTouch/ low frequency vibration ColdCold

16. Temperature sensation Heat and Cold detected by free nerve endingsHeat and Cold detected by free nerve endings Method of detection not fully understoodMethod of detection not fully understood

17. Pain reception Free (dendritic) endingFree (dendritic) ending Respond to physical or chemical disturbance  perceived as painRespond to physical or chemical disturbance  perceived as pain

18. Thin vs. Thick Skin