Integument system

What makes up the integumentary system?

Skin, sweat glands, oil glands, hair, nails, nerve endings, blood vessels.

What is dermatology?

The medical field that diagnoses and treats skin disorders.

Main functions of the integumentary system?

Protection, temperature regulation, sensory reception, Vitamin D synthesis, and excretion.

3 main layers of the skin

Epidermis, Dermis, Hypodermis (Subcutaneous).

Tissue type in epidermis

Keratinized stratified squamous epithelium.

Tissue type in dermis

Dense irregular and areolar connective tissue.

Tissue type in hypodermis

Loose connective and adipose tissue.

Keratinocytes function

Produce keratin for waterproofing and protection.

Keratinocytes origin

Arise from stratum basale.

Keratinocytes life cycle

Constant mitosis, pushed upward, die at surface.

Melanocytes function

Produce melanin pigment.

Where are melanocytes found?

Deepest layer of the epidermis (stratum basale).

Melanin function

Absorbs UV rays and protects from sun damage.

Langerhans’ cells function

Act as immune cells (macrophages).

Merkel cells function

Sense touch; located where epidermis meets dermis.

Stratum corneum

Outermost layer; 20–30 layers of dead cells.

Stratum lucidum

Thin layer of dead keratinocytes; only in thick skin.

Stratum granulosum

3–5 layers; cells flatten and die.

Stratum spinosum

Several layers thick; contains melanin and Langerhans’ cells.

Stratum basale

Deepest layer; single row of cells; constant mitosis.

Thick skin location

Palms, fingertips, and soles.

Thick skin layers

Has 5 layers (includes stratum lucidum).

Thin skin location

Covers most of the body.

Thin skin layers

Has 4 layers (no stratum lucidum).

Main tissue type of dermis

Connective tissue.

Papillary layer composition

Areolar connective tissue.

Papillary layer features

Contains dermal papillae and Meissner’s corpuscles.

Dermal papillae function

Create fingerprints and increase surface area.

Reticular layer composition

Dense irregular connective tissue.

Reticular layer contents

Hair follicles, glands, blood vessels, and sensory receptors.

Main composition of hypodermis

Fat and loose connective tissue.

Function of hypodermis

Insulation and energy storage.

Sebaceous glands secrete

Sebum (oil).

Sebaceous glands function

Lubricate skin and hair; prevent water loss; inhibit bacteria.

Sebaceous gland location

Everywhere except palms and soles.

Sudoriferous glands secrete

Sweat.

Eccrine gland location

All over body; open directly to skin surface.

Eccrine gland function

Help regulate temperature and excrete waste.

Apocrine gland location

Armpits and genital areas.

Apocrine gland secretion

Sweat with fats and proteins; causes odor when broken down by bacteria.

When do apocrine glands become active?

At puberty.

Mammary glands type

Specialized apocrine glands.

Mammary glands function

Produce milk (fat, protein, sugar).

Ceruminous glands function

Produce earwax (cerumen).

Pigment in skin

Melanin.

Melanin produced by

Melanocytes.

Melanin function

Protects skin from UV damage.

Hair made of

Dead keratinized cells.

Hair color caused by

Melanin.

Hair shaft

Visible part above the skin.

Hair root

Part below skin in follicle.

Arrector pili muscle function

Causes goosebumps.

Vellus hair

Fine, soft body hair (children and women).

Terminal hair

Coarse hair (scalp, eyebrows, pubic/axillary areas after puberty).

Nails are made of

Tightly packed dead keratinized cells.

Parts of nail

Free edge, body, root.

Nail bed

Skin under nail; pink due to blood vessels.

Nail matrix

Growth area of nail.

Lunula

Half-moon at nail base; thicker area.

Cuticle

Protects nail root.

Main cause of skin cancer

UV radiation.

Basal cell carcinoma

From stratum basale; rarely spreads.

Squamous cell carcinoma

From keratinocytes; may spread.

Melanoma

From melanocytes; spreads quickly.

ABCD rule for melanoma

Asymmetry, Border irregularity, Color change, Diameter > 6mm.

First-degree burn

Only epidermis; red and painful.

Second-degree burn

Epidermis + upper dermis; blisters, pain, inflammation.

Third-degree burn

Destroys full dermis; no pain due to nerve damage; needs graft.

Rule of 9’s

Used to estimate body surface area burned.

Acne

Bacterial infection caused by blocked oil ducts.

Whitehead

Blocked oil gland under skin.

Blackhead

Blocked oil gland open to air (darkens).

Blister

Fluid between epidermis and dermis caused by friction or burns.