The Immune SystemOur Personal Army!

Skin and the Immune System

What is the purpose of your skin?

Protection-1st line of defense against disease and bacteria

What are some properties of skin?

• Tough• Durable• Porous• Elastic• Flexible• Responsive

Structure of Skin• 1st layer – Epidermis Outer Layer

– outer, thin layer– composed of dead and living cells– 25-30 layers of dead skin which sheds regularly

REMEMBER THE DRY COMMERCIAL?

Scratch your hand and spell out the word “dry”That is dead skin that flakes off!

Dead skin cells contain keratin to waterproof the skin.

Put a drop of water on your hand and watch it bead off.

Structure of Skin

• 2nd layer – Epidermis Inner Layer– living cells– cells are constantly dividing and multiplying to

replace dead cells– contains melanin to color skin and protect from solar

radiation– fingerprints

EPIDERMIS

Why do we have fingerprints?

• Identification (specific to each person – coded for by

DNA!)• Ridges for gripping

CAN YOU IMAGINE TRYING TO HOLD YOUR PENCIL WITH SLIPPERY GLOVES ON?

THAT’S WHAT IT WOULD BE LIKE WITHOUT FINGERPRINTS!

Structure of Skin

• 3rd Layer – Dermis– thick, innermost layer– used for padding and protection– blood vessels, nerves, sweat glands, and oil glands

are located in the dermis– fat deposits add cushioning and are located in

dermis– hair follicles are located in the dermis

DERMIS

Functions of Skin

• Protection• Regulating body temperature

(goosebumps/sweat)• Sense organ for pain, pressure, temperature• Maintains chemical balance

What happens when your skin gets injured?

• Small scrape – skin cells divide quickly and fill in gap• Deep wound – bleeding occurs and there are further

stages of healing that may include a scab and a scar; the cells divide to fill in the gap more slowly

What happens when your skin gets injured?

• Burns! – 1st degree – redness and death of epidermal cells– 2nd degree – blisters, scars, and damage of dermis– 3rd degree – skin function is lost, lots of scarring, epidermis and

dermis are destroyed, skin grafts are necessary

Wounds…

What causes wrinkles?

• Age!– As you get older, your skin loses its natural elasticity

and wrinkles form