Intriguing Integumentary System The Skinny on the Skin

System Anatomy *Skin*Sweat *Oil Glands *Hair*Nails

System Physiology-- PROTECTION Mechanical Damage (Injury) Mechanical Damage (Injury) Chemical Damage (acids, bases) Chemical Damage (acids, bases) Bacterial Damage Bacterial Damage UV Radiation (melanin) UV Radiation (melanin) Thermal Damage (temperature receptors) Thermal Damage (temperature receptors) Drying Out (outer layer is hard) Drying Out (outer layer is hard)

System Physiology Temperature Regulation *Rich blood supply and sweat Excretion *Urea, salt, and water

System Physiology Production of Proteins *Vitamin D Sensory Receptors *touch *pressure *pressure*pain *temperature *temperature

The Skinny on the Skin 1. Epidermis –Outer layer –Stratified Squamous 2. Dermis –Fibrous Connective - Blister - Blister –When the two layers get rubbed and separate

Subcutaneous Tissue Adipose anchors skin to organs Adipose anchors skin to organs Shock absorber Shock absorber Insulates deeper tissues Insulates deeper tissues

I. Epidermis Avascular-no blood supply (shaving) Avascular-no blood supply (shaving) Made of up to 5 layers Made of up to 5 layers

Skin Layers A. Stratum Corneum cell layers thick cell layers thick Outer layer Outer layer DEAD DEAD Contains Keratin fibers (water repellant) Contains Keratin fibers (water repellant) Constantly worn away Constantly worn away You get a new epidermis every days You get a new epidermis every days

More Skin Layers B. Stratum Lucidum Only in hairless skin Extra thick Palms of hands, soles of feet C. Stratum Granulosum *Cells die D. Stratum Spinosum

More Skin Layers Stratum BasaleStratum Basale Deepest Cell Layer of EpidermisDeepest Cell Layer of Epidermis Constantly in Cell Division (millions of new cells daily)Constantly in Cell Division (millions of new cells daily) Cells get pushed to surface as they growCells get pushed to surface as they grow Melanin is in this layerMelanin is in this layer Receives nourishment from dermis by diffusionReceives nourishment from dermis by diffusion

Diagram of the Skin Layers

F. Tanning Melanocytes produce melanin in the stratum basale Melanocytes produce melanin in the stratum basale Sunlight stimulates the melanocytes to produce melanin (brown color) Sunlight stimulates the melanocytes to produce melanin (brown color) Melanin shields the nucleus from the sun’s UV rays Melanin shields the nucleus from the sun’s UV rays

Basal Cell Carcinoma Happens when cells in stratum basale divide uncontrollably Happens when cells in stratum basale divide uncontrollably Usually Slow growing and easy to remove Usually Slow growing and easy to remove

Squamous cell carcinoma Happens in stratum spinosum Happens in stratum spinosum Grows rapidly Grows rapidly Needs to be removed and followed with radiation Needs to be removed and followed with radiation

Malignant Melanoma Cancer of melanocytes Cancer of melanocytes 50% survival rate 50% survival rate Needs removal, chemotherapy Needs removal, chemotherapy Can spread to other parts Can spread to other parts

Signs that a mole might be Cancerous A.Asymmetry – mole is not symmetrical B.Border – jagged borders C.Color – multiple colors D.Diameter – larger than ¼ inch (size of pencil eraser) E.Evolution – mole is evolving or changing

II.Dermis -Strong and Stretchy (hide) A. Papillary layer -Upper layer of dermis -Dermal papillae – give nutrients to epidermis -Ridges form Fingerprints: increase gripping, friction- hands/feet --pain and touch receptors live here

B. Reticular Layer -Deepest layer of dermis -Contains BLOOD VESSELS! -Sweat and Oil glands -Deep pressure receptors -Phagocytes to eat bacteria -Collagen fibers-keep skin hydrated -Elastic fibers-decrease with age - wrinkles Dermis - Cont

Skin Appendages Sebaceous Glands (Oil) All over the body, EXCEPT palms and soles of the feet All over the body, EXCEPT palms and soles of the feet Usually empty into a hair follicleUsually empty into a hair follicle Make SEBUM: Oil and fragmented cellsMake SEBUM: Oil and fragmented cells -Lubricant: Keeps skin soft -Prevents hair from being brittle -Chemicals that kill bacteria YukYuk -Whitehead--when oil gland is blocked -Blackhead--dries and darkens

II. Sudoriferous Glands (SWEAT) A. Eccrine -Produces sweat (water, urea, salt, uric acid) -Acidic (pH 4-6, inhibits bacteria -Found all over body -Help Regulate heat

B. Apocrine -Found in Genital and Axillary regions -Large -Secrete Fatty Acids and proteins also -ODORLESS, but stinks when bacteria eats it!

First Degree Burns Only Epidermis Damaged

Second Degree Burns Epidermis and Upper Dermis Damaged

Third Degree Burns Destroys whole thickness of skin