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Chapter
5
The Integumentary System
CHAPTER CONTENTS
Introduction
The Practice and the Practitioners
The Skin
The Epidermis
The Dermis
Subcutaneous Tissue
Keratin and Melanin
Glands within the Skin
The Structure of Hair and Nails
Common Integumentary System Disorders and Procedures
Common Abbreviations
Exercises
Pre-Quiz Checklist
Chapter Quiz
36
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CHAPTER 5
THE INTEGUMENTARY SYSTEM
37
ntegumentum is Latin for “covering” or “shelter,” and thus the skin, nails,
and hair covering our bodies is called, collectively, the integumentary system. There are only two layers of skin, the epidermis and the dermis. The
epidermis is divisible into five sublayers and the dermis into two sublayers, the
names of which will be given later. Table 5-1 lists word elements that are used in
forming terms related to the integumentary system.
I
TABLE 5-1 WORD ELEMENTS RELATED TO THE INTEGUMENTARY SYSTEM
Word or Element
corium (KO-ree-uhm)
cutis
cyan/o
-cyte
dermatomegaly (DURmah-toh-MEG-ah-lee)
dermatoplasty (dur-MAToh-plass-tee)
derm/o; dermat/o
epifollicul/o
kerat/o
leuk/o
melan/o
onych/o
onychotomy (on-ih-KOT-oh-mee)
paronychia (pahr-oh-NIK-ee-ah)
-phyte
pil/o
subsudor/i
xer/o
Type
Latin word for “skin”
Latin word meaning “skin”;
sometimes used to form a medical
phrase, such as cutis anserina, the
technical name for “goose flesh”;
cutis is also the origin of the adjective
cutaneous, which refers to the skin.
root
suffix
derm/a/t/o (skin); -megaly (enlarged)
derm/a/t/o (skin); -plasty (surgical repair)
root
prefix
root
root
root
root
root
onych/o (nail); -tomy (incision)
para- (adjacent); onych/o (nail);
-ia (condition)
suffix
root
prefix
root
root
Refers to
synonym for dermis
skin
blue
cell
disorder in which the
skin hangs in folds
plastic surgery of
the skin
skin
upon
horn-like
white
black
nail
incision into a nail
condition resulting in
inflammation around the nail
plant
hair
below
sweat
dry
THE PRACTICE AND THE PRACTITIONERS
As shown in the preceding table, dermat/o means “skin,” and as you have already
learned, -logy means “study of.” Coupling the root dermat/o with the suffix -logy gives
us the term dermatology, which names the specialty dealing with the skin. Dropping
the -y and adding -ist gives us dermatologist, the word for a physician who specializes in dermatology and who diagnoses and treats skin abnormalities.
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PART 1
THE SKIN
The skin is said to be the body’s largest organ, and since the skin covers
the entire body—more than 20 square feet on average—and weighs about
24 pounds, the claim would seem to be true. As already noted earlier, the skin is
composed of two parts: the epidermis is the outer layer, and the dermis is the
inner layer.
The Epidermis
The epidermis protects the body from the outside world, a pretty big job for
something only three one-thousandths of an inch thick. The epidermis on the
palms of our hands and the soles of our feet is somewhat thicker than that,
but even there, it is only about two one-hundredths of an inch thick. The epidermis is divisible into five sublayers, which are listed with brief descriptions in
Table 5-2.
TABLE 5-2 SUBLAYERS OF THE EPIDERMIS
Epidermal Skin Layer
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum germinativum
Brief Description
the tough, waterproof outer sublayer of the skin
the transparent, barely discernible sublayer just
below the stratum corneum
the grainy sublayer between the stratum lucidum and stratum
spinosum
the spiny sublayer just below the stratum ganulosum; contains
cells that create an immune response to protect the body
against foreign bodies that get through the first three outer
sublayers of skin
the innermost sublayer of skin, which butts against the loose
connective tissue of the dermis; forms epidermal ridges that
connect with the dermis and also gives the stratum corneum
its distinctive pattern, as in a fingerprint
The epidermis is also sometimes referred to as epithelial tissue because it is
e avascular,
which means “without blood vessels.” However, epithelial tissue is
found elsewhere in the body, and for that reason, you should remember that the phrase
epithelial tissue is NOT synonymous with the term epidermis.
The Dermis
The dermis, which may also be called the corium, has two sublayers: the papillary sublayer and the reticular sublayer, the latter being the deeper of the two.
Unlike the epidermis, the dermis contains blood vessels and nerves. So if you get a
scratch that hurts and/or bleeds, you will know that the scratch extends through
CHAPTER 5
Hair
THE INTEGUMENTARY SYSTEM
39
Stratum corneum
Stratum lucidum
Epidermis
Stratum granulosum
Stratum spinosum
Stratum germinativum
Dermis
Nerve ending
Epidermis lifted to reveal
papillae of the dermis
Epidermis
Dermis
Blood
vessels
Sebaceous gland
Papillary layer of dermis
Nerve endings
Reticular layer of dermis
Subcutaneous tissue
Sweat glands
FIGURE 5-1 A cross-sectional view of the skin. Adapted from: Stedman, TE, ed.
Stedman’s Medical Dictionary. 27th ed. Baltimore: Lippincott Williams
& Wilkins; 2000.
the epidermis and into the dermis. The dermis also contains both sebaceous (oilproducing) glands and sudoriferous (sweat-producing) glands.
the difference between corium, a synonym for the dermis, and corneum, as
e Note
in “stratum corneum,” the outermost layer of the epidermis.
Subcutaneous Tissue
A layer of subcutaneous tissue, located just beneath the dermis, is composed of
connective tissue. Synonyms for subcutaneous tissue include hypodermis, subfascia, and the fat layer because subcutaneous tissue stores lipids. The Latin word
cutis, which means “skin,” gives us the English adjectives cutaneous and subcutaneous. Although the subcutaneous tissue is, categorically speaking, separate from
the skin, its proximity and physiology dictate that it be considered in discussions
of the skin and its abnormalities (Figure 5-1).
Keratin and Melanin
Composed of keratinocytes, keratin is a protein that toughens the outer layer of
skin and is a key component in the formation of hair and nails. Melanin, a pigment
composed of melanocytes present in the dermis, gives the skin its color and provides protection against the sun’s ultraviolet (UV) rays. Hair and nails are both
composed of epithelial cells filled with keratin. Keratinocytes and melanocytes are
simply the cells that make up keratin and melanin (recall that the suffix -cyte
means “cell”).
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PART 1
Integumentary System
Glands
Sebaceous Glands
Suderiferous Glands
Produce Sebum
Produce Sweat
Lubricates
Hair and skin
Cools Skin
FIGURE 5-2 Glands, secretions, and functions of the integumentary
system.
careful to distinguish keratinocytes, which are cells that form keratin, from
e Be
keratocytes, which are cells in the cornea of the eye.
GLANDS WITHIN THE SKIN
The sebaceous and sudoriferous glands provide the skin, hair, and nails
with the secretions needed to keep the integumentary system in good health
(Figure 5-2).
THE STRUCTURE OF HAIR AND NAILS
A hair follicle is a mass of cells that forms a cavity, out of which a hair grows. The
word follicle is derived from a Latin word meaning “small sac.” Most sebaceous
glands are located close to, but are not part of, hair follicles. Although they are distinct from hair follicles, sebaceous glands share hair follicle ductwork to transmit
their oily secretions to each hair and its adjacent skin. Certain hairless areas of skin,
mostly on the face, chest, or back, contain sebaceous glands that have their own
follicles and ductwork.
Nails are composed of layers of hardened cells of the stratum corneum (the outermost sublayer of the epidermis).
CHAPTER 5
THE INTEGUMENTARY SYSTEM
41
DECIPHERING MEDICAL DOCUMENTS
Read the following excerpt from a hospital discharge statement and answer the questions:
On day two under spinal anesthesia, the left hip was pinned percutaneously with three cannulated screws.
Postoperatively she did well and was quite stable. Hematocrit was 32.0, hemoglobin 10.9.
1. Identify and analyze the word that means “through the skin.”
2. To what time period does “postoperatively” refer?
3. What kind of tests are hematocrit and hemoglobin?
A. biopsies
B. common blood tests
C. urinalysis
COMMON INTEGUMENTARY SYSTEM DISORDERS
AND PROCEDURES
Table 5-3 lists common integumentary system disorders and some of the procedures used in their diagnosis and treatment.
TABLE 5-3 COMMON DISORDERS AND PROCEDURES ASSOCIATED
WITH THE INTEGUMENTARY SYSTEM
Term
dermatitis
dermatoma
dermatomegaly
dermatomycosis
dermatopathy
dermatoplasty
epidermatitis
melanoma
onychectomy
onychomalacia
onychomycosis
onychopathy
onychoplasty
onychotomy
paronychia
Definition
inflammation of the skin
skin tumor
excessive skin, often hanging in folds
fungal infection of the skin
any disease of the skin
plastic surgery performed on the skin
inflammation of the epidermis
tumor of the melanocytes
surgical removal of a nail
softening of the nails
fungal infection of a nail
any disease of the nails
surgical repair of a nail
incision into a nail
infection around a nail
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PART 1
A STUDY TABLE
5-1
THE INTEGUMENTARY SYSTEM
Term and Pronunciation
Analysis
Meaning
STRUCTURE & FUNCTION
avascular (ah-VASS-cue-luhr)
corium (KO-ree-uhm)
cutaneous (cue-TAYN-ee-uhs)
dermis (DUR-muss)
epidermal (epp-ih-DUR-muhl)
epidermis (epp-ih-DUR-muss)
follicle (FAWL-ik-uhl)
keratin (KERR-uh-tin)
keratinocyte (keh-RAT-ih-no-site)
melanin (MELL-uh-nihn)
melanocyte (MEL-uh-no-site)
sebaceous (she-BAY-shus)
stratum corneum (STRAT-uhm
COR-nee-uhm)
sudoriferous
(soo-doe-RIFF-uh-russ)
a- (“without”); vascular (adjectival
form of the nouns vessel or vein)
from the Latin (“skin”)
from the Latin word cutis (“skin”)
from the Greek word derma (“skin”)
epi- (“upon”); dermis (“skin”);
-al (adjectival suffix)
epi- (“upon”); dermis (“skin”)
from the Latin word folliculus
(“a small sac”)
from the Greek word kera (“horn”)
from the Greek word kera (“horn”);
-cyte (cell)
from the Greek word melas (“black”)
from the Greek word melas (“black”);
-cyte (cell)
from the Latin word sebum
(“tallow” and by extension, grease,
oil, fat)
Latin phrase meaning “tough
layer of skin”
from two Latin words: sudor
(“sweat”) and fero (“to carry”)
absence of vessels or veins
synonym for dermis
adjective referring to the skin
inner layer of skin
adjectival form of epidermis
outer layer of the skin
small sac in the skin from
which a hair grows
protein that forms hair, nails,
and the tough outer layer of
skin
cell that produces keratin
dark pigment present in skin
and other parts of the body
cell that produces melanin
adjective describing an
oil-producing gland
outermost sublayer of the
epidermis
adjective describing
sweat-producing glands
COMMON DISORDERS
dermatitis (dur-muh-TY-tiss)
dermatoma (dur-muh-TOH-muh)
dermatomegaly
(DUR-mah-toh-MEG-ah-lee)
dermatomycosis
(DUR-matt-oh-MI-ko-sis)
dermatopathy
(DUR-mah-TOP-ah-thee)
epidermitis (epp-ih-dur-MY-tiss)
melanoma (mel-uh-NO-muh)
onychomalacia
(ON-ih-ko-muh-LAY-shee-uh)
derm/a/t/o (“skin”); -itis
(“inflammation”)
dermat/o (“skin”); -oma (“tumor”)
dermat/o (“skin”); -megaly
(“enlarged”)
dermat/o (“skin”); myc/o (“fungus”);
-osis (“abnormal condition”)
derm/a/t/o (“skin”); -pathy (“disease”)
epi- (“upon”); -dermis (“skin”); -itis
(“inflammation”)
melan/o (“black”); -oma (“tumor”)
onych/o (“nail”); -malacia
(“softening”)
inflammation of the skin
tumor of the skin
excessive skin, often hanging
in folds
fungal infection of the skin
any disease of the skin
inflammation of the epidermis
tumor of the melanocytes
softening of the nails
CHAPTER 5
A STUDY TABLE
5-1
THE INTEGUMENTARY SYSTEM
THE INTEGUMENTARY SYSTEM (co nt inued)
Term and Pronunciation
Analysis
Meaning
COMMON DISORDERS
onychomycosis
(ON-ih-ko-my-KO-sis)
onychopathy
(on-ih-KOP-uh-thee)
paronychia (pahr-oh-NIK-ee-ah)
onych/o (“nail”); mycosis
(“fungal infection”)
onych/o (“nail”); -pathy (“disease”)
fungal infection of a nail
any disease of the nails
para- (“adjacent”); onych/o (“nail”);
-ia (“condition”)
infection around a nail
dermat/o (“skin”); -logist
(“practitioner”)
dermat/o (“skin”); -logy (“study”)
a specialist who diagnoses and
treats skin diseases
study of the integumentary
system
derm/a/t/o (“skin”); -plasty
(“surgical repair”)
onych/o (“nail”); -ectomy (“incision”)
plastic surgery performed on
the skin
surgical removal of a nail
onych/o (“nail”); plasty (“repair”)
surgical repair of a nail
onych/o (“nail”); -tomy (“incision”)
incision into a nail
cuticle (CUE-tih-kuhl)
from the Latin word cutis (“skin”)
cyanosis (SY-uh-no-siss)
cyan- (“blue”); -osis
(“abnormal condition”)
epi- (“upon”); dermis (“skin”);
-oid (“resemblance”)
epi- (“upon”); onych/o (“nail”)
the common word used as a
synonym for the eponychium
abnormal condition signaled by
bluish discoloration of tissue
resembling the epidermis
PRACTICE & PRACTITIONERS
dermatologist
(dur-muh-TAHL-uh-jist)
dermatology
(dur–muh-TAHL-uh-jee)
SURGICAL PROCEDURES
dermatoplasty
(dur-MAT-oh-plass-tee)
onychectomy
(ON-ihk-EHK-toh-mee)
onychoplasty
(on-ihk-oh-PLASS-tee)
onychotomy (on-ih-KOT-oh-mee)
ENHANCEMENT TERMS
epidermoid (epp-ih-DURM-oyd)
eponychium
(ep-oh-NIK-ee-uhm)
follicular (fah-LIK-u-luhr)
lunula (LOON-yu-luh)
from the Latin word folliculus
(“a small sac”)
from the Latin word luna (“moon”)
onychia (oh-NIK-ih-ya)
onychoid (ON-ik-oyd)
onych/o (“nail”); -ia (“condition”)
onych/o (“nail”); -oid (“resemblance”)
piloid (PY-loyd)
pilosebaceous
(PY-lo-she-BAY-shus)
vellus (VELL-uhs)
pil (“hair”); -oid (“resemblance”)
pil/o (“hair”); sebaceous
(“oil-producing”)
from the Latin (“fleece”)
thin, transparent layer of skin
located at the nail root
adjective form of the
noun follicle
white, crescent-shaped area
of a nail
infection of a nail bed
adjective meaning nail-like in
structure or form
hair-like
adjective referring to the hair
and sebaceous glands
fine hair that covers much of
the body
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44
PART 1
ABBREVIATION TABLE 5-1
COMMON ABBREVIATIONS:
The Integumentary System
Abbreviation
BSA
derm
SPF
UV
Meaning
body surface area (used in describing skin damage assessment caused by
burns)
dermis
sun protection factor
ultraviolet
c Exercises
Exercise 5-1 Choosing the Correct Term
Fill in the blanks.
The outer and inner layers of the skin are called, respectively, the 1)__________________________ and the
2)_________________. The dermis is sometimes called the 3)_____________________________ and contains
4)_________________, or oil-producing glands, along with 5)___________________________, or sweat-producing
glands. Hair and nails are both composed of 6)_________________________________________ cells filled with
7)________________________________________, but nails are made even tougher by hardened cells of the
8)______________________, which is the outermost sublayer of the epidermis.
Exercises
Exercise 5-2 Converting Nouns to Adjectives
Convert each of the following nouns to its adjective form using one of the
following suffixes: -al, -aneous, -eous, -otic, -ular, -oid, -ous.
Noun
Adjective Form
1. vessel
____________
2. epidermis
____________
3. sebum
____________
4. cutis
____________
5. cyanosis
____________
6. follicle
____________
7. keratin
____________
CHAPTER 5
THE INTEGUMENTARY SYSTEM
45
Exercises
Exercise 5-3 Matching Terms with Definitions
Match the numbers in Column 1 with the letters in Column 2 according to
the corresponding terms and definitions they designate.
Term
1. _____ melanin
Definition
A. oil-producing glands
2. _____ epidermis
B. protein that toughens the outer layer of the skin
3. _____ lunula
C. physician who specializes in dermatology and diag-
4. _____ sebaceous
D. responsible for pigment or color of skin
5. _____ dermatologist
E. the outer layer of the skin
6. _____ stratum corneum
F. the white, crescent-shaped area of the nail
noses and treats skin abnormalities
7. _____ avascular
G. BSA
8. _____ keratin
H. without vessels or veins
9. _____ sudoriferous glands
10. _____ body surface area
I. the outermost sublayer of the epidermis
J. sweat-producing glands
Exercises
Exercise 5-4 Identifying Skin Layers
Label the following skin layers on Figure 5-3. ?
• epidermis
• dermis
• nerve endings
• stratum germinativum
• subcutaneous tissue
46
PART 1
2
1
5
3
4
FIGURE 5-3 A cross-sectional view of the skin (Exercise 5-4).
Exercises
Exercise 5-5 True, False, and Correction
Read each statement, then indicate whether you think it is true or false. If
false, fill in the correct answer in the “Correction, if False” box at the right.
True
False
Correction, if False
1. Eponychium is a thick white layer of skin
located around the knuckles.
Statement
___
___
____________
2. Stratum corneum is the inner lens aperture
of the eye.
___
___
____________
3. Piloid is a capsule-shaped cell found in the
epidermis.
___
___
____________
4. Dermatitis is an inflammation of the skin.
___
___
____________
5. Dermis refers to the life cycle of the cuticle.
___
___
____________
6. Sebaceous describes an area consisting of
several follicles.
___
___
____________
CHAPTER 5
THE INTEGUMENTARY SYSTEM
7. A sudoriferous gland produces sweat.
___
___
____________
8. Avascular is a crowded mass of veins.
___
___
____________
9. Dermatoma is a fungus infection of the skin. ___
___
____________
10. Onychoplasty is the study of skin.
___
___
____________
11. Onychectomy is the surgical removal
of a nail.
___
___
____________
12. Onychomalacia is hardening of the skin.
___
___
____________
47
Exercises
Exercise 5-6 Complete the Sentences
Fill in the missing terms to complete the sentences.
1. Hairs grow from small sacs in the epidermis called _____________.
2. A tumor of the melanocytes is referred to as _____________.
3. The white crescent-shaped moon-like area of the fingernail is called the _____________.
4. The protein _____________ forms hair, nails, and the tough outer layer of skin.
5. The outer layer of skin is the _____________.
6. The adjective _____________ signifies an absence of veins.
7. _____________ is an adjective suffix pertaining to the epidermis.
8. Dermatomycosis is a fungal infection of the _____________.
9. Any disease of the nails may be referred to as an _____________.
10. The study of the integumentary system is called _____________.
11. _____________ is the dark pigment found in skin and other body parts.
12. Epidermitis is an inflammation of the _____________.
Pre-Quiz Checklist
_____ Study the word elements specific to the integumentary system.
_____ Review the definitions and etymologies listed in the study table.
_____ Check the exercises with the answers in the Appendix; consult the study table
again to correct any errors.
48
PART 1
Chapter Quiz
Write the answers to the following questions, using the spaces provided to the right of each
question.
1. What are the two major parts of the skin called?
1. _____________________________
2. What is the function of the epidermis?
2. _____________________________
3. Which part of the skin do you know you have
3. _____________________________
_____________________________
_____________________________
injured if you have a scratch that hurts and/or bleeds?
4. What is the layer of tissue just beneath the dermis,
and what is it composed of?
5. What protein is the key component in the formation
of hair and nails?
6. What term names the types of cells that make up
the nails?
_____________________________
4. _____________________________
_____________________________
5. _____________________________
_____________________________
6. _____________________________
_____________________________
7. What is the purpose of melanin?
7. _____________________________
8. How many sublayers do the epidermis and dermis have?
8. _____________________________
9. What do sudoriferous glands secrete?
9. _____________________________
_____________________________
_____________________________
_____________________________
10. What is a lunula?
10. _____________________________
_____________________________