WGU s2: integumentary system

skin PROTECT from sun by increase melanin

Thermoregulation is how the body keeps its temperature within a normal range. When the body is too hot, it cools itself by sweating and increasing blood flow to the skin, and when it is too cold, it warms itself by shivering and conserving heat.

Vitamin D synthesis begins in the skin when ultraviolet (UVB) rays from sunlight convert a cholesterol-related molecule into vitamin D₃. This inactive form then travels to the liver and kidneys, where it is chemically changed into its active form. Active vitamin D helps the body absorb calcium and supports bone health.

Keratinocyte is just the cell that makes keratin, 90% of epidermis cells are keratinocytes

Melanocyte - 8%, absorb UV radiation

Langerhans - part of immune system

Merkel cells- receptors for touch

Epidermis layers

  • stratum corneum

  • stratum lucidum (only in hairless skin)

  • stratum granulosum

  • stratum spinosum

  • stratum basale 

  • Sebaceous glands secrete sebum to soften skin and hair

  • Regular sweat glands secrete salt and water bc the evaporation lowers body temp

    • Eccrine(Merocrine)

    • Apocrine - the premium sweat in armpits and genitals released into the hair follicle; has organic compounds that attract bacteria

  • Ceruminous glands secrete cerumen AKA earwax

Tactile corpuscles (Meissner's corpuscle)

Respond to touch

Dermis of hairless skin
Found in abundance in the hands, feet, lips, and external genitalia

Pacinian corpuscle
(lamellated corpuscles)

Respond to pressure

Located throughout the body in the dermis, subcutaneous layer, and deeper regions (e.g., muscles)

Merkel disc

Respond to touch (slowly adapting)

Fingertips, hands, lips, and external genitals

Nociceptor

Extreme temperature; physical, mechanical, or chemical irritation

Epidermis (skin) and mucous membranes

Ruffini

Respond to stretching

Dermis in hands and soles of feet

Root hair plexus

Respond to the movement of hair

Wrapped around a hair follicle
Hairy skin

Inflammation is only caused by necrosis(accidental cell death)

when cells are damaged or killed they release histamine

scar tissue is collagen rich

stratum basale is what helps with first degree burn

DEEP WOUND HEALING

  • Inflammatory phase

  • Proliferation and Migratory phase

  • Maturation and remodeling phase

CANCER

SKin cancer is caused by UV radiation from the sun

  • Basal Cell Carcinoma - long term sun exposure, little bump on skin, not threatening

  • Squamous Cell Carcinoma - long term sun exposure on squamous cells, more threatening

  • Melanoma - uncontrolled growth of melanocytes - the most fatal skin cancer

Eczema is a non fatal and annoying skin reaction - itchy and red bumps and stuff

ACNE comes from clogged hair follicles and overproduction of sebum