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

secretionsUV radiation – melanin pigment protectsThermal damage – cold/pain receptorsDessication – 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

EpidermisKeratinocytes that can make the protein keratin (become hard & tough)

DermisConnective tissue that contains glands, capillaries and nerves

EpidermisThe 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 RemovalDermabrasion

Salabrasion (rub with salt)

Cryosurgery

Excision

Latest: Q-switched lasers

Different lasers for different color pigments

Black, purple, red easiest

Yellow, green hardest

Burns: 1st Degree

1st 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

PsoriasisSilvery, scaly patches of skin overgrowth

Prevalence 2 – 3 %

Onset: 15-25 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 matchBorder irregularity: borders are not smooth but exhibit indentationsColor: 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