BN Ch.16 The Integumentary System

Question 1

Describe the structures and main functions of the skin.

Answer 1

• Structure
• The integumentary (covering) system is composed of the skin and its accessory structures: hair, nails, and glands. Cutaneous means “of the skin.”
• Function
  
  • Primary functions of the integumentary system are:
    
    • Protection
    • Thermoregulation (temperature regulation)
    • Metabolism,
    • Sensation,
    • Communication
    • Storage
  • The skin produces substances that aid in protection and metabolism.
  • Secreted oil provides waterproofing and protects the skin from drying and cracking.
  • Perspiration helps eliminate waste products and helps in cooling.

Question 2

Explain the functions of keratin and melanin.

Answer 2

• A fibrous protein, keratin, which creates a waterproof barrier and is the body’s true protector.
  
  • It prevents most microorganisms from penetrating unbroken skin.
• Melanin gives color to hair, skin, and other structures
  
  • Melanocytes are cells within the epidermis that, through a complex process, create the pigment melanin

Question 3

Identify the structures and functions of a fingernail or toenail.

Answer 3

• Structure:
  
  • Nail Plate
  • Nail Body
  • Nail Bed:
    
    • Epidermis under the nail
  • Lunula:
    
    • White, half-moon-shaped area at base of nail; white color is caused by air mixed with keratin.
  • Nail Matrix:
    
    • Where nail growth occurs
    • Part of nail grove
  • Cuticle (Eponychium):
    
    • Band of epidermis covering nail bed; called “hangnail” when it splits
  • Nail Groove (root)
  • Bone
• Nails are tightly packed cells of the horny layer of the epidermis and help protect the sensitive tips of fingers and toes.
• They also help a person grab and pick up objects.
• The nail is made up of keratinized dead cells
• Nail growth occurs in the nail matrix.
• New cells push older cells away from the nail bed at a rate of approximately 1 mm per week.
• A fingernail lost through trauma takes about 3–5 months to regrow, and a toenail takes about 12–18 months to regrow.
• A nail will continue to regrow as long as the live cells in the nail bed remain undamaged.
• Nails normally reflect a pinkish tone because of rich vascular areas in the fingers.
• When gentle pressure is applied and released, the nail becomes lighter white but quickly returns to a pink color.
• Unhealthy nails or slow blood return may point to poor circulatory status, several nutritional deficiencies, and emotional conditions.

Question 4

Compare and contrast the functions of sudoriferous and sebaceous glands.

Answer 4

• The Sebaceous glands (oil glands):
  
  • Lie close to the hair follicles, into which they usually drain.
  • Sebum is the oily secretion of these glands; it travels to the surface of the skin through hair follicles.
  • Sebum helps make the skin soft and hair glossy.
  • Sebum prevents drying of the skin, thereby protecting it from cracking.
    
    • Cracked skin can lead to infection and can allow foreign substances to be absorbed.
  • Sebum also helps waterproof the top layer of the epidermis (stratum corneum).
  • Sebaceous secretions increase at puberty.
  • Sebum may trap bacteria in the pores, causing inflammation or infection (“pimples” or acne).
• The Sudoriferous glands (sweat glands):
  
  • Located in the dermis.
  • One inch of skin contains 750– 2,000 sweat glands.
  • The three types of sudoriferous glands are
    
    • Apocrine
    • Eccrine
    • Mammary glands
• Apocrine sweat glands:
  
  • Become active during puberty, secreting a thick, oily, milky sweat into hair follicles.
  • Apocrine glands are most numerous in the axillae, pubic region, areolae of the breasts, external ear canals, and eyelids.
  • The nominal odor from these glands gives each person an individual scent.
  • Skin surface bacteria cause apocrine sweat to become odoriferous.
    
    • A “cold sweat” occurs when emotional stressors, such as anxiety or fear, stimulate these glands.
• Eccrine sweat glands
  
  • Distributed widely over the body but are especially numerous on the upper lip, forehead, back, palms, and soles.
  • There are no eccrine glands on the lips themselves or on the glans penis.
  • Eccrine glands secrete sweat into numerous ducts that empty into pores (tiny holes in the skin) and respond to external and internal heat.
  • Perspiration (sweat) is nearly 100% water, with trace amounts of urea, uric acid, salts, and other elements.
  • The primary function of perspiration is to assist in body temperature regulation by providing a cooling effect.
  • Perspiration also moisturizes the skin and excretes wastes through the pores.
  • In some diseases, the skin increases its capacity as an excretory organ, which may be a sign of pathology.
  • (Diaphoresis refers to excessive perspiration.)
• Mammary glands:
  
  • Secrete milk and are a third, specialized type of sudoriferous gland.

Question 5

Define radiation, convection, evaporation, and conduction; give an example of each.

Answer 5

• Radiation:
  
  • The diffusion or dissemination of heat by electromagnetic waves.
  • Example The body gives off waves of heat from uncovered surfaces.
• Convection:
  
  • The dissemination of heat by motion between areas of unequal intensity.
  • Example: An oscillating fan blows currents of cool air across the surface of a warm body.
• Evaporation:
  
  • The conversion of a liquid to a vapor.
  • Example: Body fluid in the form of perspiration and insensible loss is vaporized from the skin.
• Conduction:
  
  • The transfer of heat to another object during direct contact.
  • Example: The body transfers heat to an ice pack, causing the ice to melt.

Question 6

Explain the mechanism and purpose of “goosebumps” (“goose flesh”).

Answer 6

• Blood vessel constriction, shivering, and “goose flesh” are thermoregulation processes that help warm the body.
• When the body becomes too cool, dermal capillaries constrict (narrow), reducing the amount of heat lost through the skin.
• This constriction of superficial capillaries also causes the skin color to change from its normal color to a more pale color.
• The reflex action of shivering helps produce added heat, and goose flesh raises the hairs in the skin to provide insulation.
• The more subcutaneous fat a person has, the better the body’s ability to insulate itself.
• If a person has excess subcutaneous fat, it will be more difficult for that person to remain cool in a hot environment.

Question 7

Discuss the skin’s role in sensory awareness.

Answer 7

• The skin receives stimuli from the outside world, providing a dynamic interaction between external and internal environments (sensory awareness). This is part of the skin’s role in protection.
• Nerve endings in the dermis register pain and pleasure, as well as hot and cold, vibration, and pressure, and provide these stimuli to the brain.
• Some areas are more sensitive than others, such as the fingertips.
• The body may react with a reflex response, for example, by withdrawing the hand from a hot stove. (Reflexes are discussed in later chapters.)
• The skin can also detect comfortable sensations, such as a loving touch.
• The skin and blood vessels are involved in foreplay, lovemaking, and sexual response.
• Much communication between a newborn and its parents comes via touch.
• Nurses also use therapeutic touch in client care.
• Communication also occurs through facial movements and changes in skin color.

Question 8

Name five changes that occur in aging skin.

Answer 8

• Melanin is either lost or migrates and clusters in the epidermal layer
• Epidermal and dermal layers flatten.
• Skin becomes thinner.
• Glandular secretion decreases
• Capillary bed in dermis becomes more friable (fragile)— blood can ooze into dermis
• Capillaries leak small amounts of blood into tissues
• Individual may have loss of sensation
• Loss of elasticity in dermis, loss of subcutaneous layer of fat, and loss of collagen fibers

Question 9

Describe four ways to protect the skin from damage.

Answer 9

• The skin and accessory structures guard the body from invasions by pathogens and other foreign substances.
• Retarding body fluid loss
• Assisted in heat regulation
• Excreting waste products

Question 10

__________ are patches of melanin clustered together on the skin.

Answer 10

Freckles

Question 11

The __________ is the outermost protective layer of the skin.

Answer 11

Epidermis

Question 12

Microorganisms cannot penetrate unbroken skin because of the presence of __________.

Answer 12

Keratin

Question 13

Melanin is a brown-black pigment produced by __________ which are found mostly in the basal layer of the epidermis.

Answer 13

melanocytes

Question 14

__________ is a skin condition in which the melanocytes stop making melanin, causing distinct, localized areas of white.

Answer 14

Vitiligo

Question 15

The integumentary system is responsible for maintaining the body’s internal temperature through a process called __________.

Answer 15

thermoregulation

Question 16

__________ plays a role in absorbing calcium from the body’s gastrointestinal tract.

Answer 16

Calcitrol

Question 17

What is the thin superficial layer on the body?

Answer 17

Epidermis

Question 18

The thick layer of living tissue below the epidermis.

Answer 18

Dermis

Question 19

The layer on top of the muscle

Answer 19

Hypodermis

Question 20

Write the correct sequence from outer to inner layers of the skin in the boxes provided below.

1. Hypodermis
2. Epidermis
3. Dermis

Answer 20

2. Epidermis
3. Dermis
4. Hypodermis

Question 21

What is the integumentary system composed of?

Answer 21

The integumentary system is composed of the skin and its accessory structures, including hair, nails, and glands.

Question 22

What is the function of the stratum basale or stratum germinativum?

Answer 22

The function of the stratum basale or stratum germinativum is germinating new cells. This is the deepest level of the epidermis, where the process of mitosis (division and replication of cells) occurs.

Question 23

How are fingerprints formed?

Answer 23

The dermis reaches up into the epidermis, causing ripples on the skin surface that form the finger- prints.

Question 24

What is the purpose of the subcutaneous
tissue?

Answer 24

The purpose of the subcutaneous tissue is to attach the epidermal and dermal layers to underlying organs. It helps in the formation and storage of lipocytes (fat cells), and it cushions and protects the underlying areas of the skin. The subcutaneous tissue also acts as a heat insulator.

Question 25

What are the three types of sudoriferous or sweat glands?

Answer 25

• The three types of sudoriferous glands are
  
  • Apocrine
  • Eccrine
  • Mammary glands

Question 26

What is the role of nerve endings?

Answer 26

The role of nerve endings is to register pain and pleasure.

Question 27

The nurse answers a client’s questions regarding the integumentary system and helps the client learn about mechanisms of heat loss, heat production, and heat conservation. 1. What should the nurse accurately measure as an indicator of sudden physiologic changes that occur in the client’s body?

Answer 27

The nurse should accurately measure the body temperature of the client. Body temperature is an indicator of physiologic changes occurring in a person’s body.

Question 28

A nurse measures the body temperature of a 25-year-old client with fever and finds that it is increasing rapidly. What can the nurse do to reduce the body temperature of the client?

Answer 28

• The nurse should place a cool cloth on the client’s forehead or give the client a tepid bath, so that the heat can be transferred by conduction.
• Conduction is the transfer of heat from one object to another by direct contact.

Question 29

A client whose skin has developed a bluish hue is diagnosed by the healthcare provider as having cyanosis. What causes cyanosis, and what should the nurse monitor in such a case?

Answer 29

Cyanosis is a condition caused by hypoxia, or lack of oxygen in the bloodstream. It can also occur because of hypothermia or a severe decrease in body temperature.

The nurse should monitor the oxygen level in the client’s bloodstream and should also check the body temperature of a client who has developed cyanosis.

Question 30

What should the nurse know about vasoconstriction in the extremities?

Answer 30

Vasoconstriction can occur when blood needs to be directed away from the periphery (i.e., the skin) and moved toward the major organs of the body, such as the heart and brain, to maintain homeostasis (regulation of blood pressure and cardiac output) in the body.