Integumentary Vocab and Identification

Cutaneous Membrane

The skin proper, consisting of the epidermis and dermis layers.

Keratin

Fibrous protein that provides strength, durability, and waterproofing to skin, hair, and nails.

Keratinization

Process by which cells move from deep layers to surface, accumulating keratin and eventually dying to form protective barrier.

Epidermis

Outermost layer of skin;.

Epidermis - Make up

stratified squamous epithelial tissue that is avascular (no blood vessels). Contains 4-5 layers depending on location

Epidermis - Image

Dermis

Middle layer of skin

Dermis - Make up

Made up of connective tissue. Contains blood vessels, nerves, hair follicles, and glands. Has two sublayers

Dermis - Image

Hypodermis (Subcutaneous Layer)

Deepest layer beneath dermis.

Hypodermis (Subcutaneous Layer) - Make up

Composed of adipose and areolar connective tissue. Provides insulation, energy storage, and shock absorption.

Hypodermis (Subcutaneous Layer) - Image

Stratum Basale

Deepest layer of epidermis.

Stratum Basale - Make up

Single layer of stem cells that continuously divide. Contains melanocytes.

Stratum Basale - Image

Stratum Spinosum

Layer above stratum basale.

Stratum Spinosum - Make up

Several layers of keratinocytes connected by desmosomes. Contains Langerhans cells.

Stratum Spinosum - Image

Stratum Granulosum

Middle layer

Stratum Granulosum - Make up

3-5 layers of flattened cells containing keratohyalin granules. Cells begin to die here.

Stratum Granulosum - Image

Stratum Lucidum

Clear layer found only in thick skin (palms, soles).

Stratum Lucidum - Make up

Consists of 2-3 layers of dead, transparent cells.

Stratum Lucidum - Image

Stratum Corneum

Outermost layer of epidermis

Stratum Corneum - Make up

20-30 layers of dead, flattened, keratin-filled cells that are continuously shed.

Stratum Corneum

Keratinocytes

Produce keratin protein. Migrate from basal layer to surface over ~30 days. Most abundant cell type in epidermis.

Melanocytes

Cells that produce melanin pigment. Located in stratum basale. Protect nucleus from UV radiation.

Langerhans Cells

Immune cells in stratum spinosum. Part of body's defense system against pathogens.

Merkel Cells

Sensory cells in stratum basale that detect light touch when paired with nerve endings (tactile discs).

Melanin

Primary pigment determining skin color. Protects against UV radiation. Stored in melanosomes.

Melanin

Eumelanin

Brown/black type of melanin. More common in darker skin tones.

Pheomelanin

Red/yellow type of melanin. More common in lighter skin tones and red hair.

Melanosomes

Vesicles containing melanin that are transferred from melanocytes to keratinocytes.

Melanosomes

Carotene

Yellow/orange pigment obtained from diet (vegetables). Contributes to skin color, especially in palms and soles.

Cyanosis

Blue-purple discoloration of skin due to low oxygen levels in blood.

Erythema

Redness of skin due to increased blood flow (sunburn, inflammation, emotion).

Jaundice

Yellow discoloration due to excess bilirubin in blood (liver dysfunction).

Papillary Layer

Upper layer of dermis

Papillary Layer - Make up

Areolar connective tissue with dermal papillae projecting into epidermis.

Papillary Layer

Reticular Layer

Lower layer of dermis.

Reticular Layer - Make up

Dense irregular connective tissue with collagen and elastin fibers.

Reticular Layer

Dermal Papillae

Projections of papillary dermis into epidermis. Create fingerprints and increase surface area for attachment.

Dermal Papillae

Lines of Cleavage (Langer Lines)

Natural tension lines in skin created by collagen fiber arrangement. Important for surgical incisions.

Sebaceous Glands

Oil glands associated with hair follicles. Produce sebum to lubricate skin and hair, inhibit bacterial growth.

Sebaceous Glands

Sebum

Oily secretion from sebaceous glands. Contains lipids that waterproof and protect skin.

Sudoriferous Glands

Sweat glands. Two types

Eccrine (Merocrine) Glands

Most common sweat glands. Produce watery sweat for temperature regulation. Abundant on palms, soles, forehead.

Eccrine (Merocrine) Glands

Apocrine Glands

Sweat glands associated with hair follicles. Located in armpits, groin, around nipples. Produce protein-rich secretion.

Apocrine Glands

Ceruminous Glands

Modified apocrine glands in ear canal that produce earwax (cerumen).

Mammary Glands

Modified apocrine sweat glands that produce milk in females.

Hair Follicle

Structure in dermis where hair grows. Composed of epithelial and connective tissue layers.

Hair Follicle

Hair Shaft

Visible portion of hair above skin surface.

Hair Root

Portion of hair within follicle, from bulb to skin surface.

Hair Bulb

Enlarged base of hair follicle containing matrix and dermal papilla.

Hair Matrix

Growing region in bulb where cell division produces hair shaft. Contains trichocytes and melanocytes.

Hair Papilla

Cluster of cells in hair bulb that directs hair growth and supplies nutrients.

Trichocytes

Specialized cells in hair matrix that produce hair shaft.

Arrector Pili Muscle

Smooth muscle attached to hair follicle. Contraction causes "goosebumps" and hair to stand up.

Hair Cuticle

Outermost layer of hair shaft. Overlapping scales that protect inner layers.

Hair Cortex

Middle layer of hair shaft. Contains most of hair's mass and determines strength and color.

Hair Medulla

Central core of hair shaft. May be absent in fine hair.

Nail Plate (Nail Body)

Visible portion of nail made of dead, keratinized cells.

Nail Root

Portion of nail embedded in skin at base.

Nail Matrix

Growing region under nail root where new nail cells are produced.

Nail Bed

Tissue beneath nail plate that nourishes growing nail.

Lunula

Pale crescent visible at base of nail. Represents visible part of matrix.

Lunula

Free Nerve Endings

Detect pain, temperature

Tactile (Merkel) Discs

Sense of touch and pressure

Lamellated Corpuscles

Sense Vibrations

Transepidermal Water Loss

Normal process of water evaporation through skin.

Anhidrosis

Inability to sweat normally.

Hyperhidrosis

Excessive sweating.

Alopecia

Hair loss or baldness.

Hirsutism

Excessive hair growth, especially in women.