Major roles of the Major roles of the Integumentary SystemIntegumentary System

protectionprotection maintenance of normal maintenance of normal

body temperaturebody temperature storage (of fat)storage (of fat) synthesis (of vitamin D)synthesis (of vitamin D) excretion (of salts, water excretion (of salts, water

and wastes in sweat)and wastes in sweat) sensory perceptionsensory perception

The Skin: 3 Major layersThe Skin: 3 Major layers

Did You Did You Know?...Know?...

At 8-10 At 8-10 pounds, the pounds, the skin is bodies skin is bodies largest organ!largest organ!

The EpidermisThe Epidermis

The The epidermisepidermis is the outer is the outer layer of skin. The thickness layer of skin. The thickness of the epidermis varies in of the epidermis varies in different types of skin. It is different types of skin. It is the thinnest on the ______ the thinnest on the ______ at .05 mm and the thickest at .05 mm and the thickest on ______ at 1.5 mm. on ______ at 1.5 mm.

Cells of the epidermis are Cells of the epidermis are constantly sloughing off constantly sloughing off and replacing and replacing themselves…themselves…

The Epidermis cont…The Epidermis cont…5 layers5 layers Cells are shaped like Cells are shaped like

columns at the base and columns at the base and migrate upward, as dead migrate upward, as dead cells are continuously cells are continuously sloughed off at the surfacesloughed off at the surface

•stratum corneum •stratum licidum•stratum granulosum •stratum spinosum•stratum basale

Which layer of the epidermis is this?

Specialized Epidermal Specialized Epidermal Cells Cells The The melanocytemelanocyte- produces pigment - produces pigment

(melanin) (melanin) The The Langerhans'Langerhans' cell- frontline defense of cell- frontline defense of

the immune system in the skin the immune system in the skin

They aid in grasping objects, scratching, and protecting fingers and toes.

The DermisThe Dermis This layer varies in This layer varies in

thickness as well, thickness as well, depending on the area depending on the area of the body. It is a mere of the body. It is a mere 0.3 mm on the eyelid 0.3 mm on the eyelid and 3.0 mm on your and 3.0 mm on your back. back.

The The dermisdermis is is composed of 3 types of composed of 3 types of tissue….tissue….

The Dermis cont…The Dermis cont…

2 types of tissue that are present 2 types of tissue that are present throughout (not in layers). throughout (not in layers).

collagencollagen elastic tissueelastic tissue

Dermis Tissue: CollagenDermis Tissue: Collagen

Collagen is the most abundant and Collagen is the most abundant and important structural protein in your important structural protein in your body. It strengthens and supports body. It strengthens and supports many body tissues from the outside many body tissues from the outside creating an “extracellular matrix.”creating an “extracellular matrix.”

Dermis: Elastic tissueDermis: Elastic tissue

Elastic protein fibers made by cells called Elastic protein fibers made by cells called fibroblastsfibroblasts provide protection for tissues provide protection for tissues underneath the dermis as well as the underneath the dermis as well as the pliability we associate with the skin.pliability we associate with the skin.

Specialized Dermal CellsSpecialized Dermal Cells

erector pili muscle cellserector pili muscle cells support hair follicles. support hair follicles. oil (sebaceous) glands, scent glandsoil (sebaceous) glands, scent glands, and , and

sweat glandssweat glands are associated with the follicle. are associated with the follicle. Blood vesselsBlood vessels and and nervesnerves course through this course through this

layer. The nerves transmit sensations of pain, layer. The nerves transmit sensations of pain, pressure itch, and temperature, and blood pressure itch, and temperature, and blood vessels facilitate gas exchange.vessels facilitate gas exchange.

The Importance of GlandsThe Importance of Glands

Sweat glandsSweat glands play play an important role in an important role in keeping the body coolkeeping the body cool

sebaceous glandssebaceous glands secrete secrete sebumsebum which which has waterproof and has waterproof and antimicrobial antimicrobial propertiesproperties

What makes these hairs stand on end? Why?

Can you name structures 1-4?

Layer 3: The Layer 3: The SubcutaneousSubcutaneous

Also referred to as the “Also referred to as the “hypodermishypodermis,,” ” this layer of the skin is composed this layer of the skin is composed primarily of primarily of adipose tissueadipose tissue (fat). This (fat). This layer plays a key role in insulating the layer plays a key role in insulating the body and regulating the temperature of body and regulating the temperature of the skin. the skin.

The hypodermis can vary significantly in The hypodermis can vary significantly in thickness and incorporates larger blood thickness and incorporates larger blood vessels and nerves.vessels and nerves.

NailsNails

Your nails extend from the Your nails extend from the epidermis and contain a epidermis and contain a tough protein called tough protein called keratinkeratin. They play an . They play an important role in grasping important role in grasping objects, scratching, and objects, scratching, and protecting fingers and protecting fingers and toes. toes.

Did you Know?Did you Know?

Your fingernails grow about 5 times Your fingernails grow about 5 times faster than your toenails!faster than your toenails!

HairHair

Also composed of the Also composed of the protein keratin hair protein keratin hair acts as an effective acts as an effective insulator between you insulator between you and the environment.and the environment.

hair follicles originate hair follicles originate

in the dermis.in the dermis.

Did You Know?Did You Know?

Hair can grow as Hair can grow as little as 0.1 inches little as 0.1 inches per month or as fast per month or as fast as 0.5 inches per as 0.5 inches per month depending month depending on genetics and on genetics and your diet.your diet.

Aging and the integumentary system

Marked declines in: Cell division in stratum basale Melanocyte production Glandular activity Hair follicle function Elastic fiber function in dermis Blood supply to skin Rate of repair

Disorders of the skin

•Lesions and tumors•infections (bacterial, viral, fungal, parasitic)•inflammatory reactions and allergies•Genetic diseases•acne

Anatomy of a PimpleAnatomy of a Pimple