Chapter 12 - Skin: The Integumentary System

sebaceous glands

secrete sebum that lubricates skin and discourages growth of bacteria on the skin, located in dermis layer, closely associated with hair follicles

sweat glands

help regulate body temperature and water content by secreting sweat

hair

helps control the loss of body heat

nails

protect dorsal surface of the last bone of each toe and finger

epidermis

outermost layer

epithelial tissues

form a protective covering

squamous epithelial tissue

upper layer of epidermis

basal layer

lowest layer of the epidermis

keratin

fibrous, water-repellent protein

melanocytes

produce and contain melanin

melanin

pigment that determines the color of the skin

dermis (corium)

layer below epidermis, contains connective tissue, blood and lymph vessels, and nerve fibers

sensory nerve endings

sensory receptors for stimuli

collagen

tough yet flexible fibrous protein material

mast cells

release heparin and histamine

heparin

anticoagulant, release in response to injury

histamine

release in response to allergens; causes allergic response

adipose tissue

fat

cellulite

dimpled fat around the buttocks and thighs

lipocytes (fat cells)

manufacture and store large quantities of fat

sebum

oily substance released through ducts opening into the hair follicles, moves onto the surface and lubricates the skin, slightly acidic which discourages the growth of bacteria on the skin

sudoriferous glands

tiny, coiled sweat glands

apocrine glands

sweat glands found at hair follicles

eccrine glands

sweat glands that open onto the skin

pores

opening on skin’s surface

perspiration

secreted by sweat glands, up to 1qt of liquid is perspired daily, cools the body

hidrosis

production of excretion of perspiration

mammary glands

milk-producing, modified sweat glands, sometimes classified with integumentary system

hair fibers

rod-like structures, tightly fused, dead protein cells filled with hard keratin, darkness and color determined by melanin produced by the melanocytes

hair follicles

sacs that hold the root of the hair fibers, shape determines whether hair is straight or curly

arrector pili

tiny muscles fibers attached to the hair follicles that cause the hair to stand erect, contract in response to cold or fright

unguis

fingernail or toenail, keratin plate, protects the dorsal surface of the last bone of each finger or toe

nail plate

translucent, molded to surface

nail bed

skin underneath nail plate

free edge

portion not attached to nail bed

lunula

half-moon-shaped region; place where new keratin cells form

cuticle

band of epidermis attached to the surface of the nail

nail root

fastens the nail to the finger or toe

dermatologist

physician specializing in diagnosing and treating disorders of the skin

plastic surgeon

physician specializing in surgical restoration and reconstruction of body structures

cosmetic/plastic surgeons

perform operations that are usually done for aesthetic rather than medical reasons, Ex. breast augmentation, liposuction, facelifts

acne vulgaris

triggered by hormones in puberty, pustular eruptions of the skin, overproduction of sebum around the hair follicle

comedo

noninfected lesion

whitehead

closed comedo

blackhead

open comedo

epidermoid cyst (sebaceous cyst)

closed sac found just under the skin, contain yellow, fatty material

seborrheic dermatitis

overactivity of sebaceous glands

seborrheic keratosis

benign skin growth, has a waxy or pasted-on look

anhidrosis (hypohidrosis)

lacking sweat in response to heat

diaphoresis

profuse sweating

heat rash (prickly heat)

intensely itchy rash

heat stroke (sunstoke)

caused by prolonged exposure to high temperatures

hyperhidrosis

excessive sweating

sleep hyperhidrosis (night sweats)

hyperhidrosis during sleep, potential causes: menopause, medications, infectious diseases

folliculitis

inflammation of the hair follicles

trichomycosis axillaris

superficial bacterial infection of the hair shafts

excessive hairiness (hirsutism)

excessive body and facial hair in women, usually occurs in a male pattern

alopecia

baldness

alopecia areata

autoimmune disorder that attacks the hair follicles

alopecia totalis

loss of all the hair on the scalp

alopecia universalis (AU)

total loss of hair on all parts of the body

androgenic alopecia

most common type of hair loss, male pattern baldness: receding hairline, female pattern baldness: thinning hair

clubbing

abnormal curving of the nails

koilonychia

spoon nail, outer surface of the nail is concave

onychia (onychitis)

inflammation of the nail bed

onychocryptosis

ingrown toenail

onychomycosis

fungal infection of the nail

onycholysis

separation of the nail plate from the nail bed

paronychia

acute or chronic infection of the skin fold around a nail

acanthosis nigricans

skin condition characterized by dark, velvety patches that appear in skin folds such as neck, armpits, or groin

age spots

solar lentigines or liver spots

albinism

genetic condition, deficiency or absence of pigment

chloasma

melasma or the mask of pregnancy

vitiligo

skin condition resulting from the destruction of melanocytes

contusion

injury to tissues without breaking the skin, accumulation of blood withing the skin

ecchymosis

bruise, large, irregular area of purplish discoloration

purpura

multiple purple discolorations, smaller than ecchymosis and larger than petechiae

petechiae

very small, pinpoint hemorrhages

hematoma

usually caused by an injury, swelling of clotted blood trapped in the tissues, often named for the area where it occurs

lesions

pathologic change of tissue due to disease or injury

crust

scab, collection of hard, dried serum and blood

eschar

crust-like tissue found in a full-thickness wound

erosion

wearing away of a surface

macule

discolored flat spot, less than 1cm in diameter, such as a freckle

nodule

solid, raised skin lesion

papule

small, raised red lesion

plaque

scaly, solid raised area

scales

flakes or dry patches

verrucae

warts, small hard skin lesion

wheal

welt, small bump that itches, can appear as urticaria (hives)

abscess

closed pocket containing pus, caused by a bacterial infection

purulent

producing or containing pus

exudate

fluid, such as pus, leaking out of an infected wound

cyst

abnormal sac containing gas, fluid, or semisolid material

pustule

pimple, small, circumscribed lesion containing pus

vesicle

small blister containing watery fluid; less than .5cm in diameter

bulla

large blister, usually more than .5cm in diameter

abrasion

superficial layers of skin are scraped or rubbed away

fissure

groove or crack-like break in the skin

laceration

torn or jagged wound or an accidental cut wound