1. INTEGUMENTARY SYSTEM
THE STRUCTURES

2. See figure 5-2 on page 73 and leave open to reference back to
LAYERS OF THE SKIN
Epidermis
Dermis
Subcutaneous
See figure 5-2 on page 73 and leave open to reference back to

3. EPIDERMIS Outer layer; no blood vessels present (avascular)
Stratum corneum
Outermost of three epidermal layers
Made of dead cells
Contains keratin: protein that renders the skin dry and provides a waterproof covering
Stratum germinativum
Undergoes continuous cell division
Deepest epidermal layer
Contains keratinocytes and melanocytes

4. Epidermis continued… Melanocytes and melanin Papillae
Melanocytes make melanin
Melanin: protein which protects the skin against the UV rays of the sun
Papillae
Ridges in the stratum germinativum
Come from the dermal layer and push into the stratum germinativum
Pronounced in the fingers, soles of the feet, and palms of the hands and raise the skin into permanent ridges
Prevents slipping when grabbing objects
What do these papilae create?

5. DERMIS Thicker, inner layer Connective tissue
Blood vessels: aid in regulating body temp.
Dilate to bring warmed blood to surface be cooled (when warm)
Constrict bring warmed blood closer to vital organs (when cold)
This dilation or constriction cannot be maintained for long periods of time
Nerve endings
Those for touch are near the surface and those for pressure are deeper
Muscles
Hair follicles
Oil and sweat glands
Fat cells

6. SUBCUTANEOUS Hypodermal layer or superficial fascia
Not a true part of the integumentary system
Consists of loose connective tissue and about ½ of the body’s stored fat (adipose)
Attaches the integumentary system to the surface muscles underneath

7. APPENDAGES Hair Nails Glands Sudoriferous/Sweat Sebaceous/Oil
Related ducts

8. HAIR
Distributed over most of the surface of the body and composed of a root shaft, outer cuticle layer, and inner medulla
Length, thickness, type, and color of the hair vary with the different parts of the body
Cortex and medulla
Cortex: the outer cuticle layer and consists of elongated, keratinized, nonliving cells; hair pigment is located here
Medulla: inner cuticle layer

9. continued Root and shaft
Root: part of the hair that is implanted in the skin
Shaft: projects from the skin surface
Hair follicle: in-pocketing of the epidermis where the root is embedded
Papilla: contains capillaries which nourish the hair follicle cells
Arrector pili muscle: smooth muscle that is attached to each hair follicle on the side toward which it slopes
When stimulated it contracts and causes the skin to pucker around the hair (called “goosebumps”)

10. LOOK AT FIGURE 5-3 ON PAGE 76

11. NAILS
Some disease conditions may be revealed by the color of a person’s nails. (Look on the bottom of page 76, the table and figure)
Matrix
Nail bed where the nail forms
Epidermal cells first appear as elongated cells
Keratin
Elongated cells then fuse together to form hard, keratinized plates

12. GLANDS Sudoriferous/Sweat Sebaceous/Oil
Perspiration is 99% water with only small quantities of salt and organic materials (waste products)
Distributed over the entire skin surface
Sebaceous/Oil
Sebum: thick, oily substance that protects the skin; lubricates the skin, keeping it soft and pliable
Discussed more in the next section: Function