Key Terms

Albinism.................. 118.
Arrector pili muscle.......... 119
Basal cell carcinoma......... 125
Callus................... 116 ..
Corium.................... 118
Corns.................... 116.
Cortex.................. 119 ..
Cuticle.................. 119 ..
Cyanosis.................. 118
Dermis................... 113.
Desmosomes............... 116
Epidermis................. 113
First-degree burns.......... 119
Full-thickness burns......... 119
Hair...................... 118

Hair follicle............... 119.

Hypodermis ................ 118

Keratin .................... 116

Keratinization............. 116.

Lunula................... 122.

Malignant melanoma........ 125

Medulla................. 119 ..

Melanocytes.............. 117.

Melanin................. 117 ..

Nail bed................. 122 ..

Nail body.................. 122

Nail root.................. 122

Papillary portion............ 118

Partial-thickness burns....... 119

Reticular portion ............ 118

Chapter

6

Root.................... 119 ..

Sebaceous glands........... 122

Sebum.................. 122 ..

Second-degree burns........ 119

Shaft................... 119

Squamous cell carcinoma ..... 125

Strata (stratum)............ 116

Stratum basale............ 117.

Stratum corneum........... 116

Stratum germinativum ....... 117

Stratum granulosum........ 116

Stratum lucidum............ 116

Stratum spinosum.......... 116

Sweat glands.............. 123

Third-degree burns .......... 119

Introduction

The integumentary system is made up of the skin and its
appendages. See Concept Map 6-1: Integumentary Sys-tem.
The appendages or modifications of the skin are hair, nails,
sebaceous, ceruminous, and sweat glands. The word
integument means a covering, and the skin of an average
adult covers well over 3000 square inches of surface area of
the body. The skin weighs about 6 pounds (this is nearly
twice the weight of the brain or the liver). It receives
-approximately one-third of all the blood circu-lating
through the body. It is flexible yet rugged and un-der
normal conditions can repair and regenerate -itself. Our
skin is almost entirely waterproof. It protects us from the
harmful ultraviolet rays of the sun through special

pigment-producing cells. It is an effective barrier to most

harmful chemicals, keeping them from entering our inter-

nal environment. It participates in the dissipation of water

through sweating and helps regulate our body temperature.

The Layers Of The Skin

Our skin consists of two main layers (Figure 6-1). The

epidermis (ep-ih-DER-mis) is a layer of epithelial tissue

that can further be divided into sublayers. It is found on top

of the second layer of the skin called the dermis. This is a

layer of dense connective tissue that connects the skin to

tissues below it, like fat and muscle. Beneath the dermis is

the subcutaneous layer, sometimes called the hypodermis.

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