Integumentary System

Epidermis

top layer of skin

Dermis

middle layer of skin

Hypodermis

the layer of skin beneath the dermis, which serves as a storage repository for fat

stratum corneum

the most superficial layer of the epidermis consisting of dead cells

stratum lucidum

a layer of the epidermis found only in the thick skin of the fingers, palms, and soles

stratum granulosum

3rd layer of the epidermis where cells stop reproducing and start to die

stratum spinosum

second deepest layer of epidermis

stratum basale

the deepest layer of the epidermis consisting of stem cells capable of undergoing cell division to form new cells

Melanocytes

cells that produce melanin

melanin

A pigment that gives the skin its color

cyanosis

a bluish discoloration of the skin resulting from poor circulation or inadequate oxygenation of the blood.

Carotene

the yellow pigment of the skin

Merkel cells

touch receptors in the skin

Langerhans cells

epidermal macrophages that help activate the immune system

Keratinocytes

The most abundant epidermal cells, they function mainly to produce keratin.

cutaneous carcinoma

Skin cancers originating from epithelial cells

Melanoma

skin cancer originating in a mole, most dangerous type of skin cancer

Asymmetry

Used to identify melanoma. Mole does not show symmetry.

Border

Used to identify melanoma, the edges of the mole are not defined.

Color

Used to identify melanoma, the mole contains more than one color in it.

Diameter

Used to identify melanoma, the mole is bigger than the head of a pencil eraser.

Evolving

Used to identify melanoma, the mole changes over time.

permanent tattoo

placed into the dermis. The ink molecules are too large for the immune system to break down.

henna tattoo

placed on the epidermis. Not permanent because it sheds after 2 weeks.

Cellulite

Dimpling of the skin, caused by herniations of fat within the hypodermis.

stretch marks

extreme stretching of the dermis where collagen fibers tear, leaving scars.

Abrasion

scrape of the skin due to some type of friction.

Avulsion

An injury in which soft tissue is torn completely loose or is hanging as a flap.

puncture

a small hole made by a sharp object

laceration

a cut, tear in the skin

1st degree burn

Only the epidermis is burned (red, painful, and edema)

2nd degree burn

thermal damage to the first & second layers of the skin (epidermis and dermis) Blisters will appear, and may break making the skin appear moist. Can be red or white color depending on the thermal agent. (hot water may make them appear pale) *Most painful

3rd degree burn

thermal damage to all three layers of the skin, also cooks blood vessels, so it appears to be dry and leathery- color depends on agent

Hemostasis

Stoppage of bleeding by creating a platelet plug

inflammation

a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.

Inflammatory phase of wound healing

Lasts 4-6 days; first WBC's get to the cite to ingest cell debris & bacteria. Then macrophage arrive & continue that same work while also releasing growth factors that stimulate epithelial cells & blood vessel growth. Fibroblasts are attracted by these growth factors, and fill in the wound to get ready for the next stage of healing.

Proliferative phase of wound healing

Granulation tissue forms
Epithelialization occurs
Requires fibroblast proliferation, collagen formation, wound contraction

Remodeling phase of wound healing

Last up to one year, reorganizes the collagen to produce a more elastic, stronger collagen for the scar tissue.

Vitamin D

Vitamin produced in the skin with the help of UV light

hair shaft

The portion of hair that projects above the epidermis

hair root

The part of the hair located below the surface of the epidermis.

sebaceous glands

secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis

merocrine glands (eccrine)

an exocrine gland with secretions released from a cell in secretory vesicles via exocytosis. EX: sweat glands

apocrine glands

Sweat glands that release the apical portion of the cell with the secretion. Located in the pubic and underarm areas that secrete thicker sweat, that produce odor when they come in contact with bacteria on the skin.
Other examples: Mammary, Ceruminous

holocrine glands

Exocrine glands whose secretions are made up of disintegrated cells, the thickest of the secretions.

Nails

protective coverings on the ends of the fingers and toes made up of keratin.

Poliosis

Lack of pigmentation in hair, causing the hair to be white/gray.

Fingerprints

impressions created by the papillary layer of the dermis, often called dermal ridges.

Eumelanin

Produces brown to black pigments in the hair

Pheomelanin

Produces blonde to red pigments in the hair

Hematoma

A pooling of blood

bruise

an injury where blood vessels in the skin are broken, but the skin is not cut or opened

touch receptors

The nerve endings that detect pressure on your skin

arrector pili muscle

An involuntary muscle fiber attached to the underside & base of the hair follicle, causes "goosebumps"

epithelial tissue

Sheets of tightly packed cells that line organs and body cavities; avascular

Connective Tissue

Animal tissue that functions mainly to bind and support other tissues, having a sparse population of cells and fibers like collagen and elastin scattered through an extracellular matrix. *Located in the dermis and epidermis

adipose tissue

fat

vasodilation

widening of the blood vessels that allows for increased blood flow; can cause the skin to look red in appearance.