integumentary

Dermatology

The study of the skin and its diseases.

Functions of the Skin

Protection, thermoregulation, cutaneous sensation, vitamin D production, blood reservoir, immunity, excretion of waste, water retention, and nonverbal communication.

Protection

Provides a physical barrier against bacterial and viral invasion, and physical trauma.

Thermoregulation

The process of regulating body temperature through sweat production and blood flow adjustment.

Cutaneous sensation

The ability to detect and respond to stimuli on the skin via sensory receptors.

Vitamin D production

Begins when UV light hits special molecules in the skin, converting it to active form in kidneys and liver.

Blood Reservoir

The skin can store large supplies of blood.

Epidermis

The outer layer of the skin composed of keratinized stratified squamous epithelium.

Melanocytes

Cells that synthesize and store melanin, found in the deepest layers of the skin.

Keratinocytes

The most numerous cells in the epidermis that produce keratin and form a protective layer.

Langerhans Cells

Macrophages in the epidermis that activate the immune system and present pathogen fragments.

Merkel Cells

Tactile cells in the epidermis that detect touch and are associated with nerve endings.

Stratum basale

The deepest layer of the epidermis where cell division occurs and produces keratinocytes.

Stratum spinosum

The layer of the epidermis that is 8-10 layers thick with tightly packed dividing keratinocytes.

Stratum granulosum

A layer of the epidermis that stores keratohyalin, a precursor to keratin.

Stratum lucidum

A very thin layer of dead cells only found in thick skin, like palms and soles.

Stratum corneum

The most superficial layer of the skin composed entirely of dead cells.

Keratinization

The process of cells developing in the stratum basale and migrating upwards.

Papillary Layer

The upper layer of the dermis made of areolar connective tissue with dermal papillae.

Reticular Layer

The deeper layer of the dermis that provides extensibility and elasticity.

Subcutaneous Layer

The layer beneath the dermis composed of areolar and adipose tissue, also known as hypodermis.

Melanin

A brown/black pigment stored in melanocytes that protects against UV radiation.

Erythema

Redness of the skin, often due to increased blood flow.

Sebaceous Glands

Oil glands that secrete sebum to lubricate skin and hair.

Sudoriferous Glands

Sweat glands that help regulate temperature and eliminate waste.

Epidermal Derivatives

Structures such as glands, hair, and nails that develop from the epidermis.

Basal cell carcinoma

The least malignant and most common type of skin cancer, often treatable.

Squamous cell carcinoma

Skin cancer that arises from keratinocytes; can spread quickly.

Melanoma

A rare but serious skin cancer that develops from melanocytes.

ABCD rule

A rule for detecting melanoma: Asymmetry, Border, Color, Diameter.

Albinism

A genetic inability to produce melanin.

Eczema

Itchy, weeping skin lesions often resulting from allergic reactions.

Acne

Inflammation of sebaceous glands leading to pimples.

Alopecia

Hair thinning or balding.

Burns

Injuries to the skin classified into first, second, and third degree.