The Integumentary System

Integumentary System Integumentary system = Skin Nails Hair Glands Nerve endings

Integumentary System: Functions PROTECTION from: Mechanical damage Chemical damage Bacterial damage – antibacterial secretions UV radiation – melanin pigment protects Thermal damage – cold/pain receptors Dessication – keratin waterproofing

Even more functions… Helps with heat loss or heat retention – sweat glands and capillaries Helps excrete urea – perspiration Makes Vitamin D – sunlight converts cholesterol molecules in our skin

Skin Structure

2 Types of Skin Tissue Epidermis Keratinocytes that can make the protein keratin (become hard & tough) Dermis Connective tissue that contains glands, capillaries and nerves

Epidermis The Stratums Corneum Lucidum Granulosum Spinosum Basale College Life Gives Snoopy Brains

Stratum Basale These are the “stem cells” of skin As they mature, they climb the layers of epidermis Melanocytes are here and make melanin (keratinocytes gobble up the melanin)

Melanin Pigment

Melanin Pigment Protects Nucleus

Stratum Spinosum

Stratum Granulosum

Stratum Lucidum By this point, cells are full of keratin and are dead

Stratum Corneum 20 to 30 layers of dead skin cells filled with keratin Waterproofing material This layer is thicker on palms and soles “Beauty is only skin deep”?!

Harlequin Ichthyosis Autosomal recessive Generate in 1 day the amount of skin a normal person would generate in 14 days Constant care, moisturizing, bathing to remove keratin layer Oldest living person is 24 Blind from corneal abrasions

Harlequin Ichthyosis

Dermis: Papillary and Reticular

The Dermis – Home of the Tattoo

Tattoo Removal Dermabrasion Salabrasion (rub with salt) Cryosurgery Excision Latest: Q-switched lasers Different lasers for different color pigments Black, purple, red easiest Yellow, green hardest

Burns: 1 st Degree 1 st degree: only epidermis is damaged Heal in 2 to 3 days without a problem Sunburn without blistering

Burns: 2nd Degree Injury to the epidermis and part of the dermis Characterized by pain, redness, swelling, and blisters Still enough epithelial cells to regenerate “Partial-thickness” burn

Burns: 3rd Degree Worst Entire epidermis and dermis is destroyed No more stem cells, no blood supply No nerve endings (no pain, but only at first) Must skin graft

Examples of Burns

Rules of Nines

Skin Grafting

Albinism: Melanocytes, but no melanin

Albinism

Visual Problems in Albinism

Vitiligo: Destruction of Melanocytes

Psoriasis Silvery, scaly patches of skin overgrowth Prevalence 2 – 3 % Onset: years of age Thought to be autoimmune

Cold Sores Viral infection Herpes Simplex Type 1

Hansen’s Disease (Leprosy) Spinalonga, Greece

3 Main Types of Skin Cancer Basal cell carcinoma: most common least malignant sun-exposed areas 99% cure rate with excision

3 Main Types of Skin Cancer Squamous cell carcinoma: Shallow ulcer that won’t heal Sun-exposed areas Can grow rapidly Metastasizes (travels to lymph nodes and other parts of the body)

3 Main Types of Skin Cancer Malignant melanoma: Only about 5% of all skin cancers, but incidence is on the rise Arises from accumulated damage to DNA in a melanocyte Chance for survival: 50% ABCD rule

ABCD Rule of Malignant Melanomas Asymmetry: 2 sides of the pigmented spot do not match Border irregularity: borders are not smooth but exhibit indentations Color: pigmented spot contains areas of different colors (black, brown, tan, red) Diameter: spot is larger than 6 mm in diameter (size of pencil eraser)

Skin Appendages Sebaceous (Oil) Glands Sweat Glands Hair and Hair Follicles Nails

Sebaceous Glands Everywhere except palms and soles Usually empty into hair follicle Makes “sebum” Keeps skin soft/moist Antibacterial Increased production during puberty When gland is blocked: whiteheads/blackheads

Sweat Glands: 2 Types Eccrine glands: make “sweat” Clear secretion of water, salts, urea, lactic acid Acidic, inhibits bacteria Apocrine glands: axilla (armpit) and genital area Contain sweat plus proteins/fats (not antibacterial)

Hair Follicles Hair follicle: makes the hair Hair root: alive Hair shaft: dead material; almost all protein Arrector pili: tiniest muscles; goose bumps

Nails Body: thickened keratin Root,nail fold and nail bed are alive Lunula: white moon