1. Chapter 6

2. Functions o protection (vestigial) o sexual attraction o insulation (head loses most of heat)

3. Location- o all external skin surfaces except palmar, plantar and labial (lips) o females have quiescent hairs - "sleeping" waiting for hormones o AKA lanugo (babies) and vellus hair in women

4. Structure of a hair o shaft is the visible part-dead part of hair o root + epithelial cells + connective tissue = follicle o hairs are alive if attached o no new follicles after birth (sorry!!!)

5. Hair Growth o 1 cm per month o There are phases of growth that are not predictable or under our control o Zn 2+ may influence hair growth or lack of growth also selenium will help (Se)

6. Arrector pili muscle o smallest muscles in body (most numerous) o one per hair o responds to cold or fear (tickle)

7. Sebaceous o produce oil (body oil) o attached to hair follicle o most numerous in scalp

8. Sebaceous o sebum is the combination of dead cells and oil o holocrine type of gland o cells break down to become the secretion of the gland

9. Sebaceous gland functions o lubricate skin o stop water loss o antibacterial action

10. Sebaceous gland pathology o plugs of sebum can block the duct (opening) o blackheads are made up of sebum o pimples - infected oil glands or hair canals (pus)

11. Sudoriferous glands AKA eccrine glands ( eccrine = water) o regulate body temperature o They make sweat!!!! o small excretory function - circumstantial evolutionary evidence (frogs) o aid in establishing a firm grip powder is used to counteract sweat!

12. Sudoriferous glands o salt is lost through sweating (must be replaced) o 1 liter per day (usually unnoticed in daily activities) o since evaporation gives the body the cooling action, humidity can lessen the effect of perspiring

13. Eccrine sweat glands o Sweat exits the skin through pores o (seen as tiny white spots in this image)

14. Apocrine sweat glands o location  axial-armpits  genital-groin

15. Apocrine sweat glands o Function  produce pheromones  chemical messenger  sexual attraction  similar to musk oil