Download Thibodeau: Anatomy and Physiology, 5/e

Thibodeau: Anatomy and Physiology, 5/e
Chapter 6: Skin and Its Appendages
The "nested" or hierarchical organization of the body centers around the progression of complexity from cells to
tissues, to organs, and then to organ systems. Many students are surprised to discover that the skin and its
appendages (nails, hair, and skin glands) are considered an organ system. Skin offers the ideal opportunity to relate
structure to function, since each is so integral to the other in this system, also called the integumentary system.
Skin functions are diverse and crucial for survival. They include protection, sensing of the environment,
excretion of salt and water, synthesis of chemicals and hormones, and control of body temperature. Structures
include the epidermis and its cell types (keratinocytes and melanocytes) and cell layers, the dermal-epidermal
junction and dermis (both papillary and reticular layers).
The basic determinant of skin color is the quantity of melanin deposited in the cells of the epidermis. The
number of melanocytes in the epidermis is about the same in all races; it is the amount of melanin pigment actually
produced by these cells that accounts for a majority of skin color variations. The appendages of the skin and their
functions are also discussed. These appendages include the hair, nails, and skin glands (sweat glands, sebaceous
glands, and ceruminous glands). A protective surface film is produced by the mixing of residue and secretions with
shedding epithelial cells (desquamation).
Homeostasis of body temperature is a critical function of the skin through the phenomena of evaporation,
radiation, conduction, and convection. The chapter concludes with a discussion of burns, including how to estimate
body surface area and how to differentiate among the types of degrees of burns.
Objectives
After students have completed this chapter, they should be able to:
1.
Define the terms integument and integumentary system.
2.
Discuss the generalized functions of the skin as an organ system.
3.
Describe the cell types and cell layers of the epidermis in thick skin and give the function of each.
4.
Discuss epidermal growth and repair.
5.
Describe the layers, structural components, and functions of the dermis.
6.
Discuss factors that influence skin color.
7.
Describe the formation, structure, and growth of hair and nails.
8.
Discuss and compare the structure and function of sweat (sudoriferous), sebaceous, and ceruminous glands.
9.
Discuss the composition and function of skin surface film.
10.
Explain how the skin functions in the homeostasis of body temperature.
11.
Explain the classification of burns into first-, second-, and third-degree.
Lecture Outline
I.
Introduction (p. 160)
II.
Structure of the Skin (Figs. 6-1, 6-2)
A.
Thin and thick skin
B.
Epidermis
1.
Cell types
2.
Cell layers (Fig. 6-1)
c.
Stratum granulosum
d.
Stratum spinosum
e.
Stratum basale
Dermal-epidermal junction (p. 164)
E.
Dermis
1.
Papillary layer (Fig. 6-1)
2.
Reticular layer (Fig. 6-1)
F.
Blisters (Box 6-2)
G.
Dermal growth and repair (p. 167)
Cleavage lines (Fig. 6-4)
Skin Color (p. 168)
Pigments
1.
Melanin (Fig. 6-5)
2.
Carotene
3.
Hemoglobin
Functions of the Skin (Table 6-1)
Protection (p. 170)
1.
Surface film
B.
Sensation (Fig. 6-3; Chapter 15)
C.
Movement without injury
D.
Excretion
E.
Vitamin D production (endocrine function)
F.
Immunity
G.
Homeostasis of body temperature
1.
Heat production
2.
Heat loss (Fig. 6-6)
3.
a.
Evaporation
b.
Radiation
c.
Conduction
d.
Convection
Homeostatic regulation of heat loss (Fig. 6-7)
Burns (p. 174)
A.
VI.
Stratum lucidum
D.
A.
V.
b.
Epidermal growth and repair (p. 163)
A.
IV.
Stratum corneum
C.
1.
III.
a.
Estimating body surface area (Figs. 6-8, 6-9)
Appendages of the Skin (p. 176)
A.
Hair (Figs. 6-10, 6-11)
B.
Nails (Figs. 6-12, 6-13)
C.
Skin glands (Fig. 6-14)
1.
VII.
VIII.
a.
Eccrine sweat glands
b.
Apocrine sweat glands
2.
Sebaceous glands (Box 6-10)
3.
Ceruminous glands
Cycle of Life: Skin (p. 180)
A.
Children
B.
Adults
C.
Older adults
The Big Picture: The Skin and the Whole Body (p. 181)
A.
Major component of body's structural framework
B.
Barrier between internal and external environment
C.
IX.
Sweat glands
1.
Waterproof envelope
2.
Protection against mechanical injuries
3.
Solar radiation
Functions
1.
Support (primary function)
2.
Protection (primary function)
3.
Body temperature regulation (Box 6-8)
4.
Production of vitamin D
5.
Free movement
6.
Sensation of external environment
Mechanisms of Disease: Skin Disorders (p. 181)
A.
Dermatosis
1.
2.
Skin infections
a.
Impetigo
b.
Tinea (Fig. 6-15)
c.
Warts
d.
Boils
Vascular and inflammatory skin disorders
a.
Decubitus ulcers (bedsores) (Fig. 6-16)
b.
Urticaria (hives)
c.
Scleroderma
d.
Psoriasis (Fig. 6-17)
e.
B.
X.
Eczema
Abnormal body temperature (Fig. 6-18)
1.
Fever
2.
Malignant hyperthermia (MH)
3.
Heat exhaustion
4.
Heat stroke
5.
Hypothermia
6.
Frostbite
Skin Cancer (Box 6-4)
A.
Basal cell carcinoma
B.
Squamous cell carcinoma
C.
Malignant melanoma
1.
Cancer vaccine (Box 6-7)