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Chapter 5
The Integumentary System
and Body Membranes
Jeanelle F. Jimenez RN, BSN, CCRN
CLASSIFICATION OF BODY
MEMBRANES

Classification of body membranes (Figure
5-1)


Epithelial membranes—composed of epithelial
tissue and an underlying layer of connective
tissue
Connective tissue membranes—composed
largely of various types of connective tissue
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CLASSIFICATION OF BODY
MEMBRANES

Epithelial membranes
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
Cutaneous membrane—the skin
Serous membranes—simple squamous epithelium on a
connective tissue basement membrane
• Types


Parietal—line walls of body cavities
Visceral—cover organs found in body cavities
• Examples


Pleura—parietal and visceral layers line walls of thoracic
cavity and cover the lungs
Peritoneum—parietal and visceral layers line walls of
abdominal cavity and cover the organs in that cavity
• Diseases


Pleurisy—inflammation of the serous membranes that line
the chest cavity and cover the lungs
Peritonitis—inflammation of the serous membranes in the
abdominal cavity that line the walls and cover the abdominal
organs
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CLASSIFICATION OF BODY
MEMBRANES

Epithelial membranes (cont.)

Mucous membranes
• Line body surfaces that open directly to the exterior
• Produce mucus, a thick secretion that keeps the
membranes soft and moist
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CLASSIFICATION OF BODY
MEMBRANES

Connective tissue membranes



Do not contain epithelial components
Produce a lubricant called synovial fluid
Examples are the synovial membranes in the
spaces between joints and in the lining of
bursal sacs
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THE SKIN

Structure (Figure 5-2)—two primary layers called
epidermis and dermis

Epidermis
• Outermost and thinnest primary layer of skin
• Composed of several layers of stratified squamous
epithelium
• Stratum germinativum—innermost layer of cells that
continually reproduce; new cells move toward the surface
• As cells approach the surface, they are filled with a tough,
waterproof protein called keratin; eventually cells flake off
of body
• Stratum corneum—outermost layer of keratin-filled cells

Skin pigment—produced by deepest epidermal layer;
gives color to the skin
• The brown pigment melanin is produced by specialized
cells in deepest epidermal layer
• Blisters—caused by breakdown of union between cells or
primary layers of skin
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THE SKIN

Structure (cont.)


Dermal-epidermal junction—specialized area between
two primary skin layers
Dermis
• Deeper and thicker of the two primary skin layers;
composed largely of connective tissue
• Upper papillary layer of dermis characterized by parallel
rows of tiny bumps called dermal papillae
• Ridges and grooves in dermis form pattern unique to each
individual


Basis of fingerprinting
Improves grip for tool use and walking
• Deeper reticular layer of dermis filled with network of
tough, interlacing, collagenous and stretchable elastic
fibers


Number of elastic fibers decreases with age and contributes
to wrinkle formation
Dermis also contains nerve endings, muscle fibers, hair
follicles, sweat and sebaceous glands, and many blood
vessels
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THE SKIN

Accessory structures of the skin

Hair (Figures 5-5)
• Lanugo—soft hair of fetus and newborn
• Hair follicle—epidermal tubelike structure required for
•
•
•
•
hair growth
Hair papilla—structure from which hair growth begins
Hair root—lies hidden in follicle
Hair shaft—visible part of hair
Arrector pili—specialized smooth muscle that
produces “goose bumps” and causes hair to stand
up straight
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THE SKIN

Accessory structures of the skin (cont.)

Receptors (Figure 5-2)
• Specialized nerve endings—make it possible for skin
to act as a sense organ
• Meissner’s corpuscle—capable of detecting light
touch
• Pacinian corpuscle—capable of detecting pressure
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THE SKIN

Accessory structures of the skin (cont.)

Nails (Figure 5-6)
• Produced by epidermal cells over terminal ends of
•
•
•
•
fingers and toes
Nail body—visible part of nail
Root—lies in a groove; hidden by cuticle
Lunula—crescent-shaped area nearest root
Nail bed may change color with change in blood flow
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THE SKIN

Accessory structures of the skin (cont.)

Skin glands—two types
• Sweat, or sudoriferous, glands

Eccrine sweat glands
– Most numerous, important, and wide-spread of the sweat glands
– Produce perspiration or sweat, which flows out through pores on skin
surface
– Function throughout life and assist in body heat regulation

Apocrine sweat glands
– Found primarily in axilla and around genitalia
– Secrete a thicker secretion quite different from eccrine perspiration
– Breakdown of secretion by skin bacteria produces odor
• Sebaceous glands



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Secrete oil or sebum for hair and skin
Level of secretion increases during adolescence
Amount of secretion is regulated by sex hormones
Sebum in sebaceous gland ducts may darken to form a blackhead
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THE SKIN


Skin cancer
Functions of the skin

Protection—first line of defense against:
• Infection by microbes
• Ultraviolet rays from sun
• Harmful chemicals
• Cuts and tears
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THE SKIN

Functions of the skin (cont.)

Temperature regulation
• Skin can release almost 3000 calories of body heat
per day

Mechanisms of temperature regulation
– Regulation of sweat secretion
– Regulation of blood flow close to the body surface

Sense organ activity
• Skin functions as an enormous sense organ
• Receptors serve as receivers for the body, keeping it
informed of changes in its environment
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THE SKIN

Burns
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Treatment and recovery or survival depend on
total area involved and severity or depth of the
burn
Body surface area is estimated using the “rule
of nines” (Figure 5-8) in adults
• Body is divided into 11 areas of 9% each
• Additional 1% located around genitals
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THE SKIN

Burns (cont.)

Classification of burns
• First-degree (partial-thickness) burns—only the surface
layers of epidermis involved
• Second-degree (partial-thickness) burns—involve the deep
epidermal layers and always cause injury to the upper
layers of the dermis
• Third-degree (full-thickness) burns—characterized by
complete destruction of the epidermis and dermis



May involve underlying muscle and bone
Lesion is insensitive to pain because of destruction of nerve
endings immediately after injury—intense pain is soon
experienced
Risk of infection is increased
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