Chapter 5 - Integumentary System

Dermal papillae

Peg-like folds or projections from the papillary layer of the dermis

Impetigo

Pink, fluid-filled lesions in epidermic caused by bacterial infection; most common in school-age children

Melanin

Polymer made of tyrosine amino acids; packaged in melanosomes and distributed within the deeper layers of the epidermis; major determinant of skin, eye, and hair color

Hair Follicle

Pouch of epidermis from which hair grows

Root

Remainder of the hair deep within the follicle (keratinization is ongoing)

Nail

Scalelike modification of the epidermis that forms a clear protective covering on the dorsal surface of the distal part of a finger or toe

Cleavage lines

Separations between bundles of collagen fibers in reticular region of the dermis

Desquamation

Shedding of the epidermis

Nail folds

Skin folds of the nail

Tissues found in the skin

Stratified squamous epithelium, loose connective tissue, dense irregular connective tissue

Location of healthiest cells in epidermis

Stratum basale

Stratum granulosum

Strongest and toughest epidermal layer; cell death begins here due to lack of nutrients from capillaries

Alternate name for hypodermis

Superficial fascia

Bulb

The deep end of hair located within the dermis

Blue hair

The production of air bubbles and light refraction makes hair this color

Hyponychium

The slightly thickened layer of skin that lies beneath the free edge of the nail plate

Body of nail

The visible part of the nail

Nail matrix

Thickened proximal portion of nail bed that is responsible for nail growth

Shaft

Hair that projects from the skin; keratinization is complete

Alopecia

Hair thinning or male pattern baldness (from maternal grandfather)

Dermis

Has a righ supply of nerve fibers, blood vessels, lymphatic vessels, glands, and hair follicles

Gray hair

Lack of melanin production makes hair this color

Tonofilaments

Large, cable-like parallel rays that keratin filament cells grown into

Apocrine gland

Largest but least numerous of sweat glands; found mainly in skin of axillary and genital regions; inactive until puberty

Hair Pigmentation

Made by melanocytes at base of hair follicle

Collagen

Made of three polypeptide chains coiled together to form a triple helix; Fibrous protein that gives the skin form and strength

Striae

Medical term for stretch marks

Vitamin D

Acts as a hormone and is formed from sunlight exposure; Absorbs calcium from intesting in the GI tract

Stratum spinosum

Melanin granules and Langerhans cells are most abundant in this location

Basal cell carcinoma

Most frequent type of skin cancer, but is least malignant

Eccrine glands

Most numerous of the sweat glands, particularly abundant on the palms, soles of feet, and forehead

Hair

Also called pili; flexible strands of dead keratinized cells

Rule of nines

Anterior and posterior head and neck is 9%; anterior and posterior upper limbs is 18%; anterior and posterior trunk is 36%; perineum is 1%; anterior and posterior lower limbs is 36%

Merkel cells

Associated with nerve endings involved in the sense of touch

ABCDE rule

Asymmetry, Border irregularity, Color, Diameter, Elevation

Vellus hair

Body hair of children and adult females; pale and fine hair

Cortex

Bulky layer surrounding the medulla, consists of several layers of flattened cells

Flexure lines

Dermal folds that ocur at or near joint; deep creases on palms

Terminal

Coarser, longer hair of eyebrows and scalp; may be darker; typically found on face, chest, arms, legs of adult males

Keratin

Contains carbon, hydrogen, nitrogen, oxygen, and sulfur; functions as a fibrous protein; provides protection

Arrector pili muscles

Contract under stresses of cold or fright, straighten the hair follicles, and raise the hairs, producing goosebumps

Cuticle of hair

Outer layer of hair; most heavily keratinized part of the hair; provides strength and keeps inner layers tightly compacted

Where hair is not found

Palms, soles, lips, nipples, and parts of external genitalia

Areolar connective tissue is found in

Papillary layer of dermis

Arrector pili

a smooth muscle attached to hair follicles that causes "goose bumps" to appear on the skin when contracted; contractions force sebum out of hair follicles, acts as a lubricant

Medulla

Central core of hair; consists of large cells and air spaces; contains soft keratin

Eponychium

Cuticle of the nail

Friction ridges

Epidermal ridges assumed to enhance the gripping ability of the fingers and feet; "fingerprints"

When is new epidermis made

Every 25-45 days

Hirsutism

Excessive hairiness; may result from an adrenal gland or ovarian tumor that secretes abnormally large amounts of androgens

Lanugo

Fine, delicate hairs of a fetus

Tinea

Fungal infection of the skin; includes ringworm, athelete's foot, jock itch

Appendages of the Skin

Glands, hair, blood vessels, nerve endings, nails

Trichosiderin

Iron-containing pigment producing red hair

Lunule

Region that lies over the thick nail matrix that appears as a white crescent ("half moon")

Medical name for Vitamin D

calcitriol

Lamellated granules

helps to waterproof and are major factor in slowing water loss across the epidermis