Integumentary System Protecting you from the outside world

Parts of the system Skin ◦ Layers- dermis, epidermis Hair follicles Nails Sweat Glands Sebaceous Glands *Some consider other membranes as well (ex- mucosal). We will only look at skin

Skin 2 layers ◦ Epidermis ◦ Dermis Epidermis ◦ Dead, keratinized skin, made of 5 layers of dead skin ◦ Constantly shed ◦ Holds melanocytes, make melanin, skin pigment Dermis ◦ Under epidermis ◦ Made of blood vessels, connective tissue

Within the skin Hair follicles Sweat Glands Sebaceous Glands

Hair Follicles Cells within dermis divide by mitosis ◦ As cells push up, keratinization occurs (like epidermis) ◦ Type of keratin (genetically determined) results in hair’s shape (straight, curly, etc.) Goosebumps ◦ Small muscle pulls on hair, causing to stand on end ◦ Evolutionary reaction to trap heat

Sweat Glands Small tubes beginning in dermal layer Tube exits on epidermis ◦ Excretion contains  Salt  Urea  Uric acid  Ammonia  Sugar ◦ As water evaporates, removes heat from body

Sebaceous Glands Along sides of hair follicles Create oily substance that rubs onto hair and skin Increase production during puberty,  acne!

Nails Also keratinized As keratin and air mix, white substance is left on nail nearest skin Nail bed grows nails1mm per week

Diseases Eczema Poison Ivy/Poison Oak/Poisonwood Albinism Athlete’s Foot Treeman

Eczema Any inflammation of the epidermis Result of infection, allergen, or irritant Causes redness, swelling, itching

Poison _________ Plants that secrete chemicals that irritate the skin of MOST people Includes poison ivy, poison oak, poisonwood, and cashews! Once oils washed off, rash cannot be spread ◦ You cannot spread by itching the rash unless the oil is still on you

Poisonwood rashCashew

Albinism Recessive genetic mutation results in body’s inability to produce melanin, a pigment Causes very pale skin, hair, eye coloration Same mutation exists in many mammals

Albinism

Athlete’s Foot Fungal infection, primarily of feet, but can occur anywhere on body Spread by contact ◦ This is why you wear shower shoes in college!!!

Athlete’s Foot

Treeman Rare double-genetic disorder resulting in body having difficulty regulating zinc levels Causes large wart-like growths all over body

Treeman