1. 5-7 Hair
Hair, Hair Follicles, Sebaceous Glands, Sweat Glands, and Nails
Integumentary structures
Derived from embryonic epidermis
Located in
Project through the skin surface
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2. 5-7 Hair Human Body The human body is covered with hair, : Palms Soles
Lips
Portions of external genitalia
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3. 5-7 Hair Functions of Hair Protects and
Guards openings against particles and insects
Is to very light touch
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4. 5-7 Hair The Hair Follicle Located deep in Produces nonliving hairs
Wrapped in a dense connective tissue sheath
Base is surrounded by sensory nerves (root hair plexus)
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5. 5-7 Hair Accessory Structures of Hair Arrector Sebaceous glands
Involuntary smooth muscle
Causes hairs to stand up
Produces “goose bumps”
Sebaceous glands
Lubricate the hair
Control bacteria
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6. 5-7 Hair Regions of the Hair Hair root Hair Lower part of the hair
Attached to the integument
Hair
Upper part of the hair
Not attached to the integument
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7. Figure 5-12a Hair Follicles and Hairs.
Sebaceous gland
Arrector pili muscle
Connective tissue sheath
Root hair plexus a
Hair follicles, showing the associated accessory structures

8. Figure 5-12b Hair Follicles and Hairs.
Hair Structure
The medulla, or core, of the hair contains a flexible soft keratin.
The cortex contains thick layers of hard keratin, which give the hair its stiffness.
The cuticle, although thin, is very tough, and it contains hard keratin.
Follicle Structure
The internal root sheath surrounds the hair root and the deeper portion of the shaft. The cells of this sheath disintegrate quickly, and this layer does not extend the entire length of the hair follicle.
The external root sheath extends from the skin surface to the hair matrix.
The glassy membrane is a thickened, clear layer wrapped in the dense connective tissue sheath of the follicle as a whole. b
Cross section through a hair follicle and a hair, near the junction between the hair root and hair shaft
Connective tissue sheath

9. Figure 5-12c Hair Follicles and Hairs.
Hair shaft
External root sheath
Connective tissue sheath of hair follicle
Internal root sheath
Glassy membrane
Cuticle of hair
Cortex of hair
Medulla of hair
Matrix
Hair papilla
Subcutaneous adipose tissue
Hair follicle
LM × 60 c
Histological section along the longitudinal axis of hair follicles

10. Figure 5-12d Hair Follicles and Hairs.
Connective tissue sheath of hair follicle
Glassy membrane
External root sheath
Internal root sheath
Cuticle of hair
Cortex of hair
Medulla of hair
Matrix
Hair papilla
Hair bulb
Subcutaneous adipose tissue d
Diagrammatic view of the base of a hair follicle

11. 5-7 Hair
Hair Production
Begins at the base of a hair follicle, in the dermis
The hair papilla contains capillaries and nerves
The hair bulb produces hair matrix
A layer of dividing basal cells
Produces hair structure
Pushes hair up and out of skin
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12. 5-7 Hair Hair Shaft Structure Medulla Cortex Cuticle The central
The middle layer
Cuticle
The
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13. 5-7 Hair Keratin As hair is produced, it is keratinized
Medulla contains flexible
Cortex and cuticle contain stiff
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14. 5-7 Hair Layers in the Follicle Internal External root sheath
The inner layer
Contacts the cuticle in lower hair root
External root sheath
Extends from skin surface to hair matrix
Glassy membrane
A dense connective tissue sheath
Contacts connective tissues of dermis
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15. 5-7 Hair Hair Growth Cycle Growing hair Is firmly attached to matrix
Is not growing
Is attached to an inactive follicle
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16. 5-7 Hair Hair Growth Cycle New hair growth cycle
Follicle becomes active
Produces new hair
Club hair is shed
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17. 5-7 Hair Types of Hairs hairs Terminal hairs Soft, fine
Cover body surface
Terminal hairs
Heavy, pigmented
Head, eyebrows, and eyelashes
Other parts of body after puberty
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18. 5-7 Hair Hair Color Produced by at the hair papilla
Determined by genes
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19. 5-8 Sebaceous Glands and Sweat Glands
Exocrine Glands in Skin
Sebaceous Glands ( )
Holocrine glands
Secrete sebum
Two Types of Sweat Glands
Apocrine glands
Merocrine (eccrine) glands
Watery secretions
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20. 5-8 Sebaceous Glands and Sweat Glands
Types of Sebaceous (Oil) Glands
Simple branched alveolar glands
Associated with hair follicles
Sebaceous follicles
Discharge
Sebum
Contains lipids and other ingredients
Lubricates and protects the epidermis
Inhibits bacteria
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21. Figure 5-13 The Structure of Sebaceous Glands and Sebaceous Follicles.
Lumen (hair removed)
Sebaceous follicle
Sebaceous gland
Wall of hair follicle
Basement membrane
Epidermis
Discharge of sebum
Lumen
Dermis
Breakdown of cell membranes
Mitosis and growth
Subcutaneous layer
Basal cells
Sebaceous gland
LM × 150

22. Sebaceous follicle Sebaceous gland Epidermis Dermis Subcutaneous layer
Figure 5-13 The Structure of Sebaceous Glands and Sebaceous Follicles (Part 1 of 3).
Sebaceous follicle
Sebaceous gland
Epidermis
Dermis
Subcutaneous layer

23. Breakdown of cell membranes
Figure 5-13 The Structure of Sebaceous Glands and Sebaceous Follicles (Part 2 of 3).
Lumen (hair removed)
Wall of hair follicle
Basement membrane
Discharge of sebum
Lumen
Breakdown of cell membranes
Mitosis and growth
Basal cells

24. Lumen (hair removed) Basement membrane
Figure 5-13 The Structure of Sebaceous Glands and Sebaceous Follicles (Part 3 of 3).
Lumen (hair removed)
Wall of hair follicle
Basement membrane
Basal cells
Sebaceous gland
LM × 150

25. 5-8 Sebaceous Glands and Sweat Glands
Apocrine Sweat Glands
Found in armpits, around nipples, and groin
Secrete products into
Produce sticky, cloudy secretions
Break down and cause
Surrounded by myoepithelial cells
Squeeze apocrine gland secretions onto skin surface
In response to hormonal or nervous signal
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26. Figure 5-14a Sweat Glands.
Myoepithelial cell
Sweat pore
Connective tissue of dermis
Duct
Apocrine gland cells
Duct of apocrine sweat gland
Lumen
A section through a merocrine sweat gland
Sectional plane through apocrine sweat gland
Apocrine sweat gland
LM × 459 a
Apocrine sweat glands secrete a thick, potentially odorous fluid into hair follicles.

27. 5-8 Sebaceous Glands and Sweat Glands
Merocrine
Widely distributed on body surface
Especially on palms and soles
Coiled, tubular glands
Discharge directly onto skin surface
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28. 5-8 Sebaceous Glands and Sweat Glands
Merocrine Sweat Glands (cont.)
Sensible
Water, salts, and organic compounds
Functions of merocrine sweat gland activity
Cools skin
Excretes water and electrolytes
Flushes microorganisms and harmful chemicals from skin
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29. Figure 5-14b Sweat Glands.
Sweat pore
Duct
Myoepithelial cells
Merocrine gland cells
Duct of apocrine sweat gland
Lumen
A section through a merocrine sweat gland
Merocrine sweat gland
LM × 243
Sectional plane through apocrine sweat gland b
Merocrine sweat glands discharge a watery fluid onto the surface of the skin.

30. 5-8 Sebaceous Glands and Sweat Glands
Other Integumentary Glands
Mammary glands
Produce
Ceruminous glands
Produce (earwax)
Protect the eardrum
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31. 5-8 Sebaceous Glands and Sweat Glands
Control of Glands
(ANS)
Controls sebaceous and apocrine sweat glands
Works simultaneously over entire body
Merocrine
Controlled independently
Sweating occurs locally
The main function of sensible perspiration
Works with cardiovascular system
Regulates body temperature
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