The Integumentary System

Front 1

The skin is also known as the integument, whereas the integumentary system consists of the skin and its accessory organs--the hair, nails, and cutaneous glands.

Back 1

True

Front 2

What is the scientific study and medical treatment of the integumentary system called?

Back 2

dermatology

Front 3

The skin is the body's largest and heaviest organ. In adults, it covers an area of 1.5 to 2.0 m2 and accounts for about 15% of the body weight.

Back 3

true

Front 4

What are the two layers of skin?

Back 4

a stratified squamous epithelium called the epidermis.

a deeper connective tissue layer called the dermis.

below the dermis is another connective tissue layer, the hypodermis, which is not part of the skin but is studied in conjunction with it.

Front 5

most of the skin is 1 to 2 mm thick, but it ranges from less than 0.5 mm on the eyelids to 6mm between the shoulder blades. The difference is due mainly to variation in thickness of the dermis, although skin is classified as thick or thin based on the relative thickness of the epidermis alone.

Back 5

true

Front 6

describe thick skin

Back 6

it covers the palms, soles, and corresponding surfaces of the fingers and toes. Its epidermis alone is about 0.5mm thick, due to a very thick surface layer of dead cells called the stratum corneum. It has sweat glands but no hair follicles or sebaceous (oil) glands.

Front 7

Describe thin skin

Back 7

has an epidermis about 0.1mm thick, with a thin stratum corneum. It possesses hair follicles, sebaceous glands, and sweat glands.

Front 8

what are stratum corneum?

Back 8

very thick surface layer of dead skin cells.

Front 9

What are the functions of skin?

Back 9

-Resistance to trauma and infection

-Other barrier functions (water, ultraviolet rays, chemicals etc)

-Vitamin D synthesis

-Sensation

-Thermoregulation

-Nonverbal communication

Front 10

What is the acid mantle of the skin?

Back 10

The acid mantle is a protective acidic film on the skin. Bacteria and fungi colonize the skin's surface, but their numbers are kept in check by its relative dryness, its slight acidity (pH 4-6), and certain defensive antimicrobial peptides called dermcidin and defensins.

Front 11

The skin carries out the first step in the synthesis of vitamin D, which is needed for bone development and maintenance. Where is the process completed?

Back 11

in the liver and kidneys

Front 12

What are thermoreceptors?

Back 12

Cutaneous nerve endings that monitor the body surface temperature.

Front 13

describe the epidermis

Back 13

a keratinized stratified squamous epithelium. That is the surface consist of dead cells packed with the tough protein keratin. Like other epithelia, the epidermis lacks blood vessels and depends on the diffusion of nutrients from the underlying connective tissue (hypodermis or subcutaneous fat).

Front 14

epi

derm

Back 14

epi = above, upon

derm = skin

Front 15

integument

dermat

logy

Back 15

integument = covering

dermat = skin; logy = study of

Front 16

Cells of the epidermis

Back 16

Stem Cells

Keratinocytes

Melanocytes

Tactile cells

Dendrite cells

Front 17

stem cells

Back 17

undifferentiated cells that divide and give rise to the keratinocytes. They are found only in the deepest layer of the epidermis, called the stratum basale.

Front 18

keratinocytes

Back 18

the great majority of epidermal cells. They are named for their role in synthesizing keratin.

Front 19

Melanocytes

Back 19

These are also found only in the stratum basale. They synthesize the brown to black pigment melanin.

Front 20

Tactile cells

Back 20

receptors for touch. Also found in the basal layer. The tactile cell and its nerve fiber are collectively called tactile disc.

Front 21

Dendritic cells

Back 21

found in two layers of the epidermis called the stratum spinosum and stratum granulosum. They are immune cells that originate int eh bone marrow but migrate to the epidermis and epithelia of the oral cavity, esophagus, and vagina. They stand guard against toxins, microbes, and other pathogens that penetrate into the skin. If detected, they alert the immune system.

Front 22

What are the layers of the epidermis?

Back 22

Stratum corneum

stratum lucidum

stratum granulosum

stratum spinosum

stratum basale

Front 23

In most skin, which stratum is the thickest?

Back 23

Stratum spinosum

Front 24

dendr

Back 24

dendr = tree, branch

Front 25

lucid

Back 25

lucid = light, clear

Front 26

what four important developments occur in the stratum granulosum?

Back 26

1. Keratohyalin granules release a protein called filaggrin that binds the cytoskeletal keratin filaments together into coarse, tough bundles. 2. The cells produce a tough layer of envelope proteins just beneath the plasma membrane, resulting in a nearly indestructible protein sac around the keratin bundles. 3. Membrane-coating vesicles release a lipid mixture that spreads out over the cell surface and waterproofs it. 4. Finally, as these barriers cut thekeratinocytes off from the supply of nutrients fro below, their organelles degenerate and the cells die, leaving just the tough waterproof sac enclosing coarse bundle of keratin.

Front 27

What is Dandruff?

Back 27

Dead keratinocyes exfoliate (flake off) from the epidermal surface as specks called dander. Dandruff is composed of clips of dander stuck together by sebum (oil).

Front 28

dermato

phag

Back 28

Dermato = skin; phag = eat

Front 29

Pap

illa

Back 29

pap = nipple; illa = little

Front 30

dermal papille

Back 30

the upward waves that are fingerlike extensions of the dermis.

Front 31

epidermal ridges

Back 31

the downward waves that are extensions of the epidermis

Front 32

reti

cul

Back 32

reti = network; cil = little

Front 33

hypo

derm

Back 33

hypo = below; derm = skin

Front 34

two ZONES of the dermis

Back 34

papillary layer

reticular layer

Front 35

papillary layer

Back 35

a thin zone of areolar tissue in and near the dermal papillae. This loosely organized tissue allows for mobility of leukocytes and other defenses against organisms introduced through breaks in the epidermis. This layer is especially rich in small blood vessels.

Front 36

recticular layer

Back 36

The reticular layer of the dermis is deeper and much thicker. It consists of dense irregular connective tissue. The boundary between the papillary and reticular layers is often vague.

Front 37

hypodermis or subcutaneous layer

Back 37

a layer beneath the skin that generally has more areolar and adipose tissue. It pads the body and binds the skin to the underlying tissues.

Front 38

Subcutaneous fat

Back 38

hypodermis composed predominantly of adipose tissue. It serves as an energy reservoir and thermal insulation. It is not uniformly distributed; for example, it is virtually absent from the scalp but relatively abundant in the breasts, abdomen, hips, and thighs. The subcutaneous fat averages about 8% thicker in women than in men, and varies with age.

Front 39

Epidermis

Back 39

Keratinized stratified squamous epithelium

Front 40

stratum corneum

Back 40

Dead, keratinized cells of the skin surface

Front 41

stratum lucidum

Back 41

Clear, featureless, narrow zone seen only in thick skin

Front 42

stratum granulosum

Back 42

Two to five layers of cells with dark-staining keratohyalin granules; scanty in the skin.

Front 43

stratum spinosum

Back 43

Many layers of keratinocytes, typically shrunken in fixed tissues but attached to each other by desmosomes, which give them a spiny look; progressively flattened the farther they are from the dermis. Dendritic cells are abundant here but are not distinguishable in routinely stained preparations.

Front 44

stratum basale

Back 44

Single layer of cuboidal to columnar cells resting on basement membrane; site of most mitosis; consists of stem cells, keratinocytes, melanocytes, and tactile cells, but these are difficult to distinguish with routine stains. Melanin is conspicuous in keratinocytes of this layer in black to brown skin.

Front 45

dermis

Back 45

Fibrous connective tissue, richly endowed with blood vessels and nerve endings. Sweat glands and hair follicles originate here and in hypodermis.

Front 46

Papillary layer

Back 46

Superficial one-fifth of dermis; composed of areolar tissue; often extends upward as dermal papillae.

Front 47

Reticular layer

Back 47

Deeper four-fifths of dermis; dense irregular connective tissue.

Front 48

Hypodermis

Back 48

Areolar or adipose tissue between skin and muscle.

Front 49

two forms of melanin

Back 49

a brownish black eumelanin

a reddish yellow sulfur-containing pigment, pheomelanin

Front 50

explain dark skin color

Back 50

People of different skin colors have essentially the same number of melanocytes, but in dark skin, the melanocytes produce greater quantities of melanin, the melanin granules in the keratinocytes are more spread out than tightly clumped, and the melanin breaks down more slowly. Thus, melanized cells may be seen throu

Front 51

Hair is divisible into three zones along its length:

Back 51

(1) the bulb, a swelling at the base where the hair originates in the dermis or hypodermis; (2) the root, which is the remainder of the hair within the follicle; and (3) the shaft, which is the portion above the skin surface.

Front 52

lan

vellus

Back 52

lan = down, wool

vellus = fleece

Front 53

dermal papilla

Back 53

a bud of vascular connective tissue that provides the hair with its sole source of nutrition. The hair bud grows around the dermal papilla.

Front 54

hair matrix

Back 54

a region of mitotically active cells immediately above the papilla which is the hair's growth center.

Front 55

in a cross section the hair reveals up to three layers:

Back 55

medulla

cortex

cuticle

Front 56

The medulla

Back 56

a core of loosely arranged cells and air spaces. It is most prominent in thick hairs such as those of the eyebrows, but narrower in hairs of medium thickness and absent from the thinnest hairs of the scalp and elsewhere.

Front 57

The cortex

Back 57

constitutes most of the bulk of a hair. It consists of several layers of elongated keratinized cells that appear cuboidal to flattened in the cross section.

Front 58

The cuticle

Back 58

composed of multiple layers of very thin, scaly cells that overlap each other like roof shingles with their free edges directed upward.

Front 59

The follicle is a diagonal tube that dips deeply into the dermis and sometimes extends as far as the hypodermic. It has two principal layers:

Back 59

epithelial root sheath

connective tissue root sheath

Front 60

The bulge of the epithelial root sheath

Back 60

a source of stem cells for follicle growth

Front 61

Hair receptors

Back 61

Nerve fibers which entwine each follicle and respond to hair movements.

Front 62

pilorector muscle (pilomotor muscle or arrector pili)

pili = of hair

Back 62

a bundle of smooth muscle cells extending from dermal collagen fibers to the connective tissue root sheath of the follicle.

Front 63

A given hair goes through a hair cycle consisting of three developmental stages:

Back 63

anagen

catagen

telogen

Front 64

anagen

Back 64

at any given time about 90% of the scalp follicles are in the anagen stage. In this stage, stem cells from the bulge in the follicle multipy and travel downward, pushing the dermal papilla deeper into the skin and forming the epithelial root sheath. Root sheath cells directly above the dermal papilla form the hair matrix. Here, sheath cells directly above the dermal papilla form the hair matrix. Here, sheath cells transform into hair cells, which synthesize keratin and then die as they are pushed upward away from the papilla.

Front 65

catagen stage

Back 65

Mitosis in the hair matrix ceases and sheath cells below the bulge die. The follicle shrinks and the dermal papilla draws up toward the bulge. The base of the hair keratinizes into a hard club and the hair, now known as a club hair, loses its anchorage.

Front 66

telogen

Back 66

This is the stage when the papilla reaches the bulge and the hair goes into a resting period.

Front 67

alopecia

Back 67

Thinning of the hair, or baldness.

Occurs to some degree in both sexes and may be worsened by disease, poor nutrition, fever, emotional stress, radiation, or chemotherapy.

Front 68

Pattern baldness

Back 68

condition in which hair is lost from select regions of he scalp rather than thinning uniformly across the entire scalp.

Front 69

hirsutism

Back 69

excessive or undesirable hairiness in areas that are not usually hairy, especially in women and children.

Front 70

ana

gen

cata

telo

alopecia

hirsut

Back 70

ana = up; gen = build, produce

cata = down

telo = end

alopecia = fox mange

hirsut = shaggy

Front 71

fingernails and toenails are clear, hard derivatives of the ____________

Back 71

Stratum corneum

Front 72

hyponychium

hypo = below; onych = nail

Back 72

the epidermis of the skin underlying the nail plate

Front 73

how fast does the fingernail grow?

Back 73

1 mm per week. Toenails are slightly slower.

Front 74

How can the appearance of the fingertips and nails be valuable in medical diagnosis?

Back 74

The fingertips become swollen or clubbed in response to long-term hypoxemia -- a deficiency of oxygen in the blood stemming from conditions such as congenital heart defects and emphysema. Dietary deficiencies may be reflected in the appearance of the nails. An iron deficiency, for example, may caue them to become flat or concave (spoon like) rather than convex.

Front 75

lunule

lun = moon; ule = little

Back 75

The opaque white crescent at the proximal end of a nail.

Front 76

The skin has five kinds of glands:

Back 76

merocrine sweat glands

apocrine sweat glands

sebaceous glands

ceruminous glands

mammary glands

Front 77

Sudoriferous (sweat) glands, are of two kinds:

sudor = sweat

fer = carry, bear

Back 77

apocrine

merocrine

Front 78

apocrine glands

Back 78

Occur in groin, anal region, axilla, and areola, and in mature males, in the beard area. Ducts lead into nearby follicles rather than directly to the skins surface. They do not use apocrine mode of secretion. They use exocytosis. Sweat is thicker and more milky because it has more fatty acids in it. They are scent glands that respond especially to stress and sexual stimulation. They secrete sex pheromones.

Front 79

bromhidrosis

Back 79

disagreeable body odor

Front 80

Merocrine (eccrine) sweat glands

Back 80

Over entire body, especially abundant on the palms, soles, and forehead. Function to cool the body. Excrete some of the same wastes as the kidneys. There are 3 to 4 million merocrine sweat glands in the adult skin, with a total mass about equal to one kidney.

Front 81

Myoepithelial cells

Back 81

Specialized cells found in both apocrine and merocrine sweat glands and found amid the secretory cells at the deep end of the gland. These squeeze the base of the gland, and force perspiration up the duct---particularly under conditions of over heating, nervousness, or arousal.

Front 82

Perspiration is about 99% water and has a pH ranging from 4 to 6, contributing the acid mantle that inhibits bacterial growth on the skin.

Back 82

True

Front 83

insensible perspiration

Back 83

the fact that perspiration evaporates about as fast as it is produced, so it is no notice.

Front 84

diaphoresis

dia = through; phoresis = carrying

Back 84

Under such conditions as heat, exercise, and circulatory shock, more copious sweat is produced and noticeably wets the skin.

Front 85

Sebaceous glands

seb = fat, tallow; aceous = possessing

Back 85

produce an oily secretion called sebum. They are flask-shaped, with short ducts that usually open directly onto the skin surface. These are holocrine glands with little visible lumen. Sebum keeps the skin and hair from becoming dry, brittle, and cracked.

Front 86

Ceruminous glands

cer = wax

Back 86

found only in the external ear canal, where their secretion combines with sebum and dead epidermal cells to form earwax, or cerumen.

Front 87

Mammary glands

Back 87

modified apocrine sweat glands that produce a richer secretion and channel it through ducts to a nipple for more efficient conveyance to the offspring.

Front 88

Cutaneous Glands

Back 88

Front 89

Skin Cancer

Back 89

Befalls one out of five people in the US. UV radiation from the sun damages DNA and disables protective tumor suppressor genes in the epidermal cells. One of the most common cancers, but one of the easiest to treat.

Front 90

There are three types of skin cancer named for the epidermal cells in which they originate:

These three type are also distinguished from each other by the appearance of their lesions (zones of tissue injury)

Back 90

basal cell carcinoma

squamous cell carcinoma

melanoma

Front 91

Basal cell carcinoma

Back 91

Most common type. Least deadly because it seldom metastasizes, but if neglected, it can severely disfigure the face. The lesion first appears as a small, shiny bump. As the bump enlarges, it often develops a central depression and a beaded "pearly" edge.

Front 92

Squamous cell carcinoma

Back 92

Arises from keratinocytes of the stratum spinosum. Lesions usually appear on the scalp, ears, lower lip, or back of the hand. They have a raised, reddened, scaly appearance, later forming a concave ulcer with raised edges. If untreated, tends to metastasize to the lymph nodes and can be lethal.

Front 93

Melanoma

Back 93

A skin cancer that arises from the melanocytes. It accounts for no more than 5% of skin cancers, but it is extremely aggressive and drug-resistant. Can be treated surgically if caught early, but if it metastasizes--which it does quickly--it is unresponsive to chemotherapy and is usually fatal. The average person with metastatic melanoma lives only 6 months from diagnosis, and only 5% to 14% of patients survive with it for 5 years.

Front 94

lesio

carcin

oma

Back 94

lesio = injure

carcin = cancer; oma = tumor

Front 95

Cancer Society suggest an "ABCD rule" for recognizing melanoma:

Back 95

"A" for asymmetry (one side different)

"B" for border irregularity (contour is not uniform but wavy or scalloped)

"C" for color (mixture of brown, black, tan and sometimes red and blue)

"D" for diameter (greater than 6mm)

Front 96

Burns

Back 96

The leading cause of accidental death. Burn deaths result primarily from fluid loss, infection, and the toxic effects of eschar--the burned, dead tissue.

Front 97

Burns are classified according to the depth of tissue involvement:

Back 97

First-degree

Second-degree

Third-degree

Front 98

First-degree burns

Back 98

involve only the epidermis and are marked by redness, slight edema, and pain. (sunburns)

known as partial-thickness burns

Front 99

Second-degree burns

Back 99

involve the epidermis and part of the dermis but leave at least some of the dermis intact. Known as partial-thickness burns. Severe sunburns and many scalds are second-degree burns.

Front 100

Third-degree burns (full-thickness burns)

Back 100

The epidermis and all of the dermis, and often some deeper tissues (muscle and bone) are destroyed. These are sometimes called fourth-degree burns. The skin can only regenerate from the edges because no dermis remains.

Front 101

The two most urgent considerations in treating a burn patient are:

Back 101

fluid replacement

infection control

Front 102

A patient may lose up to 75% of the blood plasma within a few hours, potentially leading to circulatory shock and cardiac arrest--the principal cause of death in burn patients.

Back 102

TRUE

Front 103

Eschar

Back 103

a slough or piece of dead tissue that is cast off from the surface of the skin, particularly after a burn injury, but also seen in gangrene, ulcer, fungal infections, necrotizing spider bite wounds, and exposure to cutaneous anthrax.

Front 104

debridement

de = un; bride = bridle

Back 104

medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue.