Integumentary Systems

Dermis vs. Epidermis

*Epidermis* - outermost layer of skin made of many sheets of flattened scaly epithelial cells - mostly dead *Dermis* - innermost layer of skin made up of mostly living cells. - Lies under the epidermis - has blood vessels, nerve endings, glands, sense organs, smooth muscle and hair follicles.

What happens if oil ducts become clogged with too much sebum, dead cells, or bacteria?

Acne

What determines hair color?

Amount of melanin

Where is Hair Produced?

At the base of the hair follicle found in the dermis layer of skin

Skin Problems

Blisters Burns Psoriasis

How are Burns classified?

By how much damage they cause

Function of Dermis Layer

Control Body Temperature • Humans are endothermic and normally have a constant body temperature of 98.6F. • To control body temperature the blood vessels in the dermis layer can narrow to conserve heat. • To cool off, blood vessels expand, warming the skin and increasing heat loss to the outside air.

Causes of Burns

Fire Hot Water Sunlight Electricity Chimicals

What is Hair?

Large column of dead cells that have been filled with keratin to provide strength

Sebum

Oil produced by the Sebaceous Glands

Sweat Glands

Operate to Cool the body: ● Nerves cause production of sweat when temperature of the body increases. ● As sweat evaporates on the skin's surface, it cools the air surrounding us making it feel cooler

Most important role of skin

Protection from bacteria, chemicals, UV rays and injury

What is the largest organ of the body?

Skin - makes up 12 - 15% of total body weight.

Advantages of thick epidermis Layers on palms and soles of feet

They are used a lot and need extra protection

What are Hair Follicles

Tube shaped pockets of epidermis cells that extend into the dermis.

Nail Matrix or Nail Root

Where the nails grow from where cells quickly divide

Function of hair

aid in protection and insulation

What is Sweat Made up of?

salt, water and other compounds

Goose bumps

when frightened or cold the smooth muscle fibers attached to hair follicles contract and pull the hair upright producing "goose Bumps

Scaling

● Associated with Psoriasis ● When cells in the outer layer of skin reproduce faster than normal and pile up on the skin's surface

Blister

● Caused by rubbing that will separate the layer of epidermis, or the dermis. ● Fluid collects between the layers

Psoriasis

● Chronic (long-lasting) skin disease characterized by scaling and inflammation 1-2 % of American's have psoriasis ● All ages and male/female ● No cure - just treatments

Third-Degree Burns

● Entire Epidermis is burned away ● May effect the Dermis Layer ● Can be fatal - because of infection and dehydration

Melanocytes

● Found in the epidermis layer ● Produce *melanin* - a dark pigment ● Amount of melanin in our skin cells determines the color of skin ● Amount of melanin is skin is determined by 1. heredity and 2. length of time the skin is exposed to UV rays (amount of time in the sun) ● More melanin is produced when the skin needs to filter out increased UV rays. ● Both dark and light skinned people have the same number of melanin producing cells, but the amount of melanin produced is different

Sebaceous Glands

● Function to create oil, or *sebum* that keeps the keratin rich epidermis flexible and waterproof. ● Sebum also coats the shaft of hairs and surface of skin to prevent water loss and lubricates and softens skin and hair ● Sebum also possible acts as mild toxin to some bacteria.

Structures of the Integumentary System

● Hair ● Nails ● Glands ● Skin

Hair vs. Nails

● Hair is produced at the base of the hair follicle found in the dermis layer of skin, while nails grow from the nail root, also called the nail matrix, an area where cells quickly divide. ● Hair is a large column of dead cells that have been filled with keratin to provide strength. While the nail cells are dividing they are filled with keratin to produce a similarly strong nail plate.

Second-Degree Burns

● May cause blistering ● Deep layers of epidermis are damaged ● Inflammation (swelling), blisters and pain

Hypodermis

● Not an official layer of skin - it is a *subcutaneous* layer - lies under the dermis layer ● is made mostly of fat and loose connective tissue insulating the body and acting as an energy reserve.

First-Degree Burns

● Only affect the epidermis ● Painful but do not blister EX: Sunburns

Epidermis

● Outer most layer of skin ● Composed of many sheets of flattened scaly epithelial cells ● Mostly Dead cells ● Washed away every 14 - 28 days ● Older cells become flattened and lose their cellular contents.

Functions of the Skin

● Protection ● Temperature Regulation ● Sensory Reception - including heat, pressure, pain biochemical synthesis (creates vitamin D)

Two Types of Glands found in the Skin

● Sweat Glands ● Sebaceous Glands

Dermis

● The innermost layer of skin Composed of living ● Lies beneath the epidermis and contains: 1. blood vessels 2. nerve endings 3. glands 4. sense organs 5. smooth muscle 6. hair follicles.

Treatments for Psoriasis

● Topical Solutions - steroids and salicylic acid creams ● Phototherapy - artificial UV light is applied ● pills/injections in extreme cases

Keratin

● Tough protein found in the basic structure of hair and nails. ● In other animals - keratin forms cow horns, reptile scales, bird feathers and porcupine quills ● When keratin producing cells (keratinocytes) die - they form a tough flexible waterproof covering on the surface of the skin