4
CHAPTER SUMMARY
Chapter 4 builds upon the cell and tissue information presented in Chapter 3. Students have already
gained an understanding of the similarities and differences between cells, and also have a working
knowledge of the various types of tissues in the body. Continuing with the theme of increasing levels
of organization, the next logical step is recognizing that various tissues combine together to form
membranes that have specific functions. Types of membranes are discussed first, with explanations
provided as to the similarities and differences between cutaneous, mucous, serous, and synovial
membranes.
The next section of the chapter delves into the mechanics of the integumentary system, which
students easily identify as their skin, and which they have just learned is also a special type of
epithelial membrane known as a cutaneous membrane. Because a majority of the body is water, the
skin prevents you from dripping all over the ground as you sit in class. The many functions of the skin
are often taken for granted, and this is a good opportunity for students to learn that as the largest organ
of the body, skin has a multitude of functions. The structure of the skin is presented, detailing the
layers and components of the epidermis as well as the dermis. Skin color in its various manifestations,
both normal and abnormal, are explained.
Accessory structures of the skin are discussed next. Cutaneous glands (sweat and
sebaceous), hair and hair follicles, and nails are all presented. Finally, an overview of
homeostatic imbalances affecting skin are outlined, including the effects of infections and
allergies, burns, and skin cancers. The chapter closes on an explanation of the developmental aspects
of the skin and body membranes, and students particularly enjoy learning about the skin’s aging
processes and what they can do to delay that process.
SUGGESTED LECTURE OUTLINE
I.
II.
I. CLASSIFICATION OF BODY MEMBRANES CLASSIFICATION OF BODY
MEMBRANES (pp. 108–110)
A.
Epithelial Membranes (pp. 108–110)
1.
Cutaneous Membrane—keratinized stratified squamous epithelium of
superficial skin
2.
Mucous Membranes (Mucosa)—moist lining of body cavities open to
exterior such as mouth and urinary tract and underlain by lamina propria
3.
Serous Membranes—lines ventral body cavities closed to exterior
a.
Parietal Layer—lines wall of ventral body cavity
b.
Visceral Layer—covers outside of organs within cavity
B.
Connective Tissue Membranes (p. 110)
1.
Bursae—lubricating sacs that reduce movement-related friction
2.
Tendon Sheaths—tube-like covering of tendons
INTEGUMENTARY SYSTEM (SKIN) (pp. 110–124)
A.
Basic Skin Functions (p. 111)
1.
Skin—protection and repair
2.
Skin Derivatives
3.
Prevent dehydration
4.
Thermoregulation
B.
C.
D.
E.
III.
5.
Assists excretion of urea and uric acid
6.
Vitamin D synthesis
Structure of the Skin (pp. 112–114)
1.
Epidermis—five strata of keratinized stratified squamous epithelium
a.
Stratum Basale—innermost zone containing melanin pigment
b.
Stratum Spinosum
c.
Stratum Granulosum
d.
Stratum Lucidum
e.
Stratum Corneum
2.
Dermis—dense connective tissue containing collagen and elastic fibers
a.
Papillary Layer—dermal papillae indent epidermis
b.
Reticular Layer—deepest skin layer containing blood vessels, sweat
and oil glands, and deep pressure receptors
3.
Hypodermis—mostly subcutaneous adipose tissue for insulation
Skin Color (p. 116)
1.
Pigments—three contribute to skin color
a.
Melanin—in epidermis
b.
Carotene—in stratum corneum and subcutaneous tissue
c.
Oxygen-Rich Hemoglobin—dermal blood vessels
Appendages of the Skin (pp. 116–120)
1.
Cutaneous Glands—exocrine glands that release secretions onto skin surface
via ducts
a.
Sebaceous (Oil) Glands—produce oily lubricating sebum
b.
Sudoriferous (Sweat) Glands
2.
Hairs and Hair Follicles
a.
Matrix—growth zone of hair bulb
b.
Arrector Pili—smooth muscle bands which create “goose bumps”
3.
Nails—scale-like modification of dermis
a.
Cuticle—thick proximal nail fold
Homeostatic Imbalances of the Skin (pp. 120–124)
1.
Infections and Allergies
a.
Athlete's Foot (Tinea Pedis)—fungus infection
b.
Boils and Carbuncles—bacterial infection
c.
Cold Sores (Fever Blisters)—herpes simplex infection
d.
Contact Dermatitis—allergic response to chemical exposure
e.
Impetigo—staphylococcus infection
f.
Psoriasis—autoimmune disorder causing red epidermal lesions
2.
Burns—tissue damage and cell death
a.
Rule Of Nines—11 body areas each accounting for approximately 9
percent of body surface area
b.
Degree Of Burns
c.
Critical Burns
3.
Skin Cancer
a.
Basal Cell Carcinoma—least malignant and most common
b.
Squamous Cell Carcinoma—grows rapidly and metastasizes to
adjacent lymph nodes
c.
Malignant Melanoma—cancer of melanocytes which metastasizes
rapidly and is fatal in 50 percent of cases
i.
American Cancer Society ABCD rule
DEVELOPMENTAL ASPECTS OF SKIN AND BODY MEMBRANES (p. 124)
A.
Lanugo—downy hair covering fetus
B.
Vernix caseosa—protects fetal skin
C.
Alopecia—hair thinning and baldness