Dr. Karen Coker Tennessee State University Integumentary System Dr. Karen Coker Tennessee State University

SKIN Skin reflects one’s personality and character Much can be learned just by looking at an individual’s skin

SKIN Wrinkles indicate mood, age, social habits, overexposure to the sun

Skin Tone Color reflects one’s ethnicity as a result of the melanin content

Melanocyte

Skin Texture The skin’s texture indicates one’s life occupation from repeated mechanical forces or weather exposure

Reflects Emotion-gestures Skin reflects one’s emotions as it moves fluidly with the underlying muscles and connective tissue.

SKIN Skin abnormalities can be a response to a disease process, injury, allergy, or medication Contact Dermatitis from a silver watch band http://www.iacdworld.org/skin/contact.htm

Wounds Skin wounds that are partial thickness heal with skin Skin wounds that are full thickness heal with scar tissue

Skin-Two Distinct Layers Epidermis and dermis Largest organ Functions Temperature regulation Excretion of sweat and electrolytes Oil secretion Vitamin D synthesis Sensation

Skin-Two Distinct Layers Epidermis Outermost layer Waterproof Protects body from infection

Skin-Two Distinct Layers Dermis Contains nerves, vessels, lymphatics, elastic fibers, sweat and sebaceous glands, hair follicles Contains collagen fibers that give skin its strength and elasticity

Skin Subcutaneous tissues and fat

5 layers to the epidermis Stratum corneum-dead cells that shed Stratum lucidum-soles and palms (thickness) Stratum granulosum Stratum spinosum Stratum basale-produces epidermal cells

Cell adherence Epithelium: Cells bind the skin cells to each other Cells bind the stratum basale of the epidermis to the dermis

Dermal-epidermal Junction Dermal papillae and epidermal pegs meet together to create a bond that will withstand friction and shear forces to the skin

Sensation Informative Protective Skin has sensors that pick up information and send that information to the brain If the skin senses danger or pain, a quick reflex to move away from the pain protects you from further injury

Skin Renewal New skin cells (keratinocytes) are located in the epidermis in the stratum basale If skin needs to heal, the fibroblasts in the dermis are the major cells involved

Prevention of fluid loss The outer most layer of the epidermis is the stratum corneum It is a barrier to fluid loss Homeostasis (balance) is maintained Water loss can cause dry skin or irritant dermatitis

Immunity In addition to the physical barrier skin provides, Langerhans cells (stratum spinosum in the epidermis: are alerted by foreign microbes that come on the skin) pH (acidic pH of 4.2-6 that is an “acid mantle” for a chemical barrier to microbes) Antimicrobial peptides and lipids (prick the microbe cell membrane and destroy its integrity, making it inactive)

Thermoregulation Skin responds to changes in temperature Dermal blood vessels: arteries constrict when cold to preserve inner body heat In heat, arteries dilate to allow more blood to circulate near the skin surface and dissipate the heat Sweat glands Eccrine sweat glands allow fluid to evaporate (apocrine sweat glands are stress related: armpits, groin)

Protection from Ultraviolet Rays Presence of melanin Provides color variation Provides protection of underlying tissue from the UV rays of the sun

Synthesis and Storage of Vitamin D Vitamin D is necessary for calcium metabolism and bone formation Stratum basale and stratum spinosum have keratinocytes that secrete Vitamin D Process is stimulated by sunlight At least 10 min per day is recommended

Aesthetics and Communication Appearance and sexual attraction Skin color Texture Hyper/hypopigmentation Apocrine sweat glands in the armpit and groin are dependent on sex hormones and they secrete sex pheromones that can influence behavior

Wound Healing Primary Intention: incision is sutured or fibrin glued or staples back together Delayed primary intention: wounds left open a few days, then sutured Secondary Intention: healing by letting it close on its own: inflammatory response, granulation tissue formation, re-epithelialization Partial thickness wounds: epithelial cell mitosis and migration

Wound Healing Hemostasis: blood clot formation (6-12 hours) Inflammation (1-7 days) Invaders killed Wound debridement Neo-angiogenesis Proliferation (6 days-8 weeks) Maturation/Remodel (2 weeks -2 years)

Hemostasis: blood clot formation (6-12 hours)

Inflammation (1-7 days)

Proliferation (6 days-8 weeks) Eschar (needs debridement) Neo-genesis Proliferation

Maturation/Remodel (2 weeks -2 years) Re-epithelialization of a wound: skin cells grow over the granulation tissue to seal the wound

Reference Text and Atlas of Wound Diagnosis and Treatment by Rose L Hamm. 2015. McGraw-Hill Education.