Chapter 6- Disease and the First Line of Defense

Integumentary System

“Covering”, also called the cutaneous. Skin - largest organ of the body. Appendages (accessory structures) - hair, glands, and nails.

Epidermis

Outermost portion, contain many layers of strata. Made of epithelial cells. No blood vessels.

derm/o

means skin

epi -

means above

Dermis

Framework of connective tissue. Contains blood vessels.

Epidermis replaces itself every ___ days.

28 days

Stratum basale (stratum germinativum)

Layer closest to the dermis; constantly dividing and pushing upward.

corn/e

(cornified, keritanized)

Stratum corneum

Uppermost layer; replaced during exfoliation.

Keratin

Protein that replaces the dead epithelial cells that protects the skin.

Melanin

Found in the deepest layer, pigment.

Melanocytes

Cells that produce the pigment.

melan/o

(dark, black)

Dermis

“True skin”, Elastic connective tissue, blood and nerve supply. Sweat glands, oil glands and hair located here.

Dermal papillae

Thick dermal skin on the tips of fingers and toes (prints), ridges and whirls determined by heredity.

Subcutaneous Layer

Hypodermis, superficial fascia. Below the dermis, connects skin to the surface muscles. Consists of loose connective tissue (adipose). Blood vessels that supple the skin come through the subcutaneous layer. Rich in nerve endings.

sub-

(under, below)

Sebum

Oily secretion; lubricates skin and hair. Opens into the hair follicle.

Vernix caseosa

“cheesy vanish”, babies are covered in this when born.

Meibomian Glands

In eyelash line, lubricate the eye.

Sebaceous cyst

Becomes blocked with sebum and grows in size.

Sudoriferous (Sweat) Glands

Coiled, tube-like found in dermis and subcutaneous tissue. Function is to cool the body.

Eccrine Sweat Glands

Throughout body; secretory portion and excretory portion extends to outside the skin through a pore.

Apocrine Sweat Glands

Armpits and groin, active in puberty, body odor.

ap/p

(separation from, derivation of)

Ceruminous glands

Ear canal; secrete ear wax (cerumen).

Ciliary glands

Edges of the eyelid.

Mammary glands

In the breasts.

Hair

Composed of keratin.

Hair follicle

Hair develops from this bulb.

Shaft

Part that shows above the skin.

Root

Portion below the skin.

Arrector pili

Muscle that raises hair.

pil/o

(hair)

Nails

Made of hard keratin.

Nail root

Growth region

Nail plate

Remainder of the nail that rests on the nail bed. Nails are clear, color shows through from bed.

Lunula

“Little moon” at proximal end of nail.

Cuticle

Seals in the nail plate, stratum corneum. Changes can indicate health problems.

Integumentary System

What is the name of the system that comprises the skin and all its associated structures?

Moving from the superficial to the deeper layers, what are the names of the two layers of the skin?

Epidermis and dermis.

What is the composition of the subcutaneous layer?

Loose connective tissue and adipose tissue, blood vessels and nerves.

What is the name of the skin gland that produces an oily secretion?

Sebaceous gland

What is the scientific name for the sweat glands?

Sudoriferous glands

What is the name of the sheath in which hair develops?

Hair follicle

Where are the active cells that produce a nail located?

Epidermis

Functions of the Skin

Protects against infection - first line of defense. Protects against dehydration - we are waterproof. Regulates body temperature - vessels constrict when we’re cold to reduce blood flow and keep heat inside; dilate when warm to help cool the body, plus sweat. Collection of sensory information.- free nerve ending and sensory receptors, such as Meissner corpuscle (touch), and Pacinian corpuscle (deep pressure). Other functions - Absorption medicine patches, sunlight. Water and electrolytes excretion, nitrogenous wastes. Vitamin D manufactured through ultraviolet light.

Discoloration

Any distinct change in skin color. Melanin is main pigment; also in hair eyeball.

Albinism

Total lack of pigment.

alb/i

(white)

Carotenemia

too much carotene in the blood, skin becomes orange

-emia

(blood)

Hemoglobin

pigment that carries oxygen in RBC

Pallor

paleness of skin; anemia

Flushing

edness of skin; fever

Cyanosis

bluish hint to skin due to lack of
oxygen; cardiac and respiratory diseases

cyan/o

(blue)

-sis

(condition, process)

Jaundice

yellowish discoloration; bilirubin
from fat digestion in liver

bili

(bile)

Lesions

Any wound or local damage to tissue

Surface lesions

rash, eruption (if raised);
localized or generalized

Erythema

redness of the skin

eryth

(red)

Macules

Neither raised or
depressed, Freckles, Measles

Papule

Firm, raised area, Chickenpox, Syphillis, Pimples, Nodule – large, firm
papule

Vesicle

Blister, small fluid-filled
sac, Chickenpox or shingles

Bulla

another term for
vesicle

Pustule

Vesicle filled with pus, Infected

Deeper Lesions

Develop from surface lesion, or trauma, Need excellent asepsis to prevent infection,
Can become systemic and cause death

Excoriation

scratch into the skin

Laceration

rough, jagged wound tearing the
skin

Ulcer

Sore, Disintegration and
death of tissue

Fissure

Crack in the skin

Superficial Burn

epidermis only, red and dry with minimal pain;
mild sunburn; first degree

Deep partial-thickness burns

epidermis and part of the dermis;
blistered, broken, and weeping surface; scalding, exposure to
flame; second degree

Full-thickness burns

full skin and sometimes underlying tissue;
broken, dry and charred; requires skin grafting; third degree

Rule of 9’s

estimation of how much surface area has been burned (page 120), Complications: infection, respiratory, circulatory from fluid and electrolyte loss

Sunburn

causes chemical
and biological changes in
skin; leads to skin cancer or
premature aging

Tissue Repair

Begins when blood has clotted and forms a
scab, Fibroblasts manufacture collagen to close the
gap

Cicatrix

scar

Keloids

excess collagen in formation of scar, Healing depends on nutrition, blood supply,
infection, and age

Factors that Affect Healing

Nutrition: needed for cell growth and
regeneration; Vitamins A and C for collagen
production, Blood supply: transport of oxygen and
nutrients; removal of wastes, Infection: promotes inflammation that
interferes with growth and repair, Age: slower to heal, lower immune response

Keratin and oily sebum

What two substances produced in the skin
help to prevent dehydration?

Dilation and constriction of the blood vessels,
and evaporation at the skin

What two mechanisms involving the skin are
used to regulate temperature?

Melanin, hemoglobin, carotene, bile

Name some pigments that give color to the skin.

Cyanosis

What is the term for a bluish discoloration caused by
insufficient oxygen?

Epithelial and connective tissues

What two categories of tissues repair themselves
most easily?

Nutrition, blood supply, infection, and age

Name four factors that affect skin healing.

Effects of Aging

Wrinkles as skin loses collagen, Dermis becomes thinner, Skin more transparent, Loss of subcutaneous fat, Hair becomes thinner and loses melanin, Sweat glands decrease in number, easily becomes overheated

Dermatosis

term for any skin disease

dermat/o

(skin)

Dermatitis

inflammation of the skin

Atopic Dermatitis (Eczema)

intense itching
and skin inflammation; starts in childhood;
sensitive to many products

Psoriasis

Chronic overgrowth of epidermis, Large, sharply outlines red flat areas covered in silvery scales, Unknown etiology, Possible immune disorder

Cancer

Most common form of cancer in US; fair skin
living in southwest, Directly caused by overexposure to UV rays

Basal Cell Carcinoma

Arise in epidermis, Face, head, neck and hands, Surgical removal

Squamous Cell Carcinoma

Arise in the epidermis, Head, face, neck, hands, Surgical removal

Melanoma

Malignant tumor of melanocytes, Originates in a nevus (mole or birthmark), Irregular in shape, Changes in color and size, Blistering sunburn, but
can show up on soles of feet

Acne

disease of sebaceous glands