1. Skin Accessories and Appendages
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Skin Accessories and Appendages

2. Appendages of the Skin Glands Hair/hair follicles Nails
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Appendages of the Skin
Glands
all exocrine glands (meaning they release secretions via ducts)
Sebaceous glands
Sweat glands
Hair/hair follicles
Nails

3. • Sebaceous (oil) gland • Hair follicle • Hair root
Figure 4.3 Skin structure.
Hair shaft
Dermal papillae
Epidermis
Papillary
layer
Pore
Appendages of skin
• Eccrine sweat gland
• Arrector pili muscle
Dermis
Reticular
layer
• Sebaceous (oil) gland
• Hair follicle
• Hair root
Hypodermis
(subcutaneous
tissue)
Cutaneous vascular plexus
Nervous structures
• Sensory nerve fiber
Adipose tissue
• Lamellar corpuscle
• Hair follicle receptor
(root hair plexus)

4. Sebaceous (oil) glands
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Sebaceous (oil) glands
Produce sebum (oil) which:
Lubricates skin/ slows water loss
Prevents brittle hair
Kills bacteria
Most empty into hair follicles; others directly onto skin surface
Highly active at puberty

5. Figure 4.7a Cutaneous glands.
Sweat
pore
Eccrine
gland
Sebaceous
gland
Sebaceous
gland duct
Dermal connective
tissue
Hair in
hair follicle
Secretory cells
(a) Photomicrograph of a sectioned
sebaceous gland (100×)

6. Sweat glands Two types: Eccrine glands Apocrine glands
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Sweat glands
Two types:
Eccrine glands
Produce sweat through pores all over skin surface
Sweat has salts, Vit. C, excretory wastes (uric acid)
Apocrine glands
Ducts empty into hair follicles
Activated at puberty; found in armpit and genital areas
Sweat that also contains fatty acids and proteins (milky or yellowish color)
Bacteria like this stuff – they create body odor when they use it

7. Function of sweat dissipate excess heat (homeostatic) Excretion
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Function of sweat
dissipate excess heat (homeostatic)
Excretion
Inhibits bacterial growth (acidic environment)
Make us feel really yucky 

8. Figure 4.7b Cutaneous glands.
Sweat
pore
Eccrine
gland
Sebaceous
gland
Dermal connective
tissue
Eccrine
gland duct
Secretory cells
(b) Photomicrograph of a sectioned
eccrine gland (205×)

9. hair Produced by hair follicle Root is enclosed in the follicle
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hair
Produced by hair follicle
Outer tissue= connective
Inner= epithelial
Root is enclosed in the follicle
Shaft (dead part) projects from surface of scalp or skin
Consists of hard keratinized epithelial cells
Melanocytes provide pigment for hair color
Hair grows from hair bulb in stratum basale

10. Figure 4.8c Structure of a hair and hair follicle.
Fibrous
sheath
Hair
follicle
Epithelial
sheath
Hair matrix (growth
zone) in hair bulb
Melanocyte
Hair papilla
containing
blood vessels
Subcutaneous
adipose tissue
(c)

11. Appendages of the Skin Arrector pili muscle Smooth muscle tissue
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Appendages of the Skin
Arrector pili muscle
Smooth muscle tissue
Pulls hairs upright when person is cold or frightened (gives us goosebumps)
You could consider this a vestigial structure- it has lost all of its function/use for humans

12. Figure 4.8a Structure of a hair and hair follicle.
shaft
Arrector
pili
Sebaceous
gland
Hair root
Hair bulb
in follicle
(a)

13. © 2015 Pearson Education, Inc.
Appendages of the Skin
Notice how the scale-like cells of the cuticle overlap one another in this hair shaft image (660×)

14. Figure 4.9 Scanning electron micrograph showing a hair shaft emerging from a follicle at the skin surface.

15. Nails Heavily keratinized = very hard Functions:
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Nails
Heavily keratinized = very hard
Stratum basale is responsible for growth
Lack of pigment makes them colorless
Functions:
Protection
Tools
Scratch an itch!

16. Appendages of the Skin Nail structures Free edge
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Appendages of the Skin
Nail structures
Free edge
Body is the visible attached portion
Nail folds are skin folds that overlap the edges of the nail
Growth occurs from nail matrix
Root of nail is embedded in skin
Cuticle is the proximal nail fold that projects onto the nail body