Integumentary System Michelle Mason, Hunter Eisenhower, Micaela Lincoln, Liam Murray

What is the integumentary system?  Organ system that protects the body from damage  Guards the body’s physical and biochemical integrity  Functions:  Waterproof, cushion, and protect deeper tissues, excrete waste, regulate body temperature, attachment point for sensory receptors, vitamin D synthesis

The Skin  The skin is the body’s integumentary system  Largest of the body’s organ systems  12% - 15% of body’s weight  Is composed of a minimum of 3 layers:  Epidermis  Dermis  Hypodermis

Epidermis  Outermost layer composed of epithelial cells  Composed of 4 layers: stratum basale, spinosum layer, stratum granulosum, stratum corneum  Has no blood supply and depends on diffusion from dermal cells for metabolic needs

Stratum Basal  Bottom most layer responsible for constantly renewing epidermal cells  Contains one row of undifferentiated columnar stem cells that divide frequently  Half of the divided cells move to the next layer to begin the maturing process  Other half stays in basal layer and divides over and over to replenish basal layer  Contains melanocytes: the cells responsible for creating melanin, the pigment responsible for skin color

Spinosum Layer  Cells transferred here change from columnar to polygonal  Cells begin to synthesize keratin  Keratin is the key component in making up the outer layer of skin, along with hair and nails.

Stratum Granulosum  Cells here have lost their nuclei and are characterized by dark clumps of cytoplasmic material  Here keratin proteins and water-proofing lipids are produced and organized

Stratum Corneum  Cells here known as coreocytes and have flattened out  Cells here are composed of mainly keratin protein which add strength but also allow absorption of water  Responsible for integrity and hydration of skin  Disruptions in this layer can result in a variety of skin problems

Dermis  2 Layers  Stratum papillare  Stratum Reticulare  Dermis layer responsible for:  Cushioning body  Sense of touch  Made up of  Collagen  Elastic Fibers  Hair Follicles

Stratum Papillare  Makes up upper part of dermis  It forms the sharp, wave shaped border of the dermis  The wavy surface increases the contact with the epidermis  Made of loose connective tissue  Connects the dermis to the epidermis

Stratum reticulare  Makes up a lower part of the dermis  Much thicker then the papillary  The protein fibers give the layer  Strength  Extensibility  Elasticity  Contains  Roots of hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels

Hypodermis  Sometimes referred to as the Subcutaneous layer and the superficial fascia  The lowermost layer of the integumentary system  It contains larger blood vessels and nerves than those in the dermis  A major storage site for adipose tissue

Contents of The Hypodermis  Cells  Fibroblasts  Adipose  Macrophages  Subcutaneous Fat  Layer of insulation to hold in heat  Assists in Homeostasis

Accessory Structures of the Skin  Sudoriferous and sebaceous glands  Hair and hair follicles  Nails

Sudoriferous and Sebaceous Glands  Sebaceous Glands: (oil glands) found surrounding hair follicles and deposit sebum, oily substance that lubricates the hair and skin, onto the hair shaft  Sudoriferous glands: (sweat glands) located in the dermis and secrete a watery substance that is important in body temperature regulation and excretion  Four types: Eccrine, apocrine, ceruminous, and mammary glands

Eccrine & Apocrine Glands  Eccrine Glands: major sweat glands of the human body; products contain mainly water, salts, and nitrogen-containing wastes  Apocrine Glands: don’t become active until after puberty; found only in the axilla, genital area, and areolae of the nipple; products contain lipids and proteins

Ceruminous & Mammary Glands  Modified suderiferous glands  Ceruminous Glands: Found in ear canal. Produce a waxy substance (cerumen) that prevents foreign substances from entering the auditory canal.  Mammary Glands: Found in breasts. Synthesize and secrete milk after appropriate hormonal stimulation.

Integumentary Illnesses  Sunburn  Athlete’s foot  Albinism  Acne  Herpes  Blisters  Rashes

Souces  m m  biobk/biobookintegusys.html biobk/biobookintegusys.html  836/epidermis 836/epidermis  science.com/_int/_en/topic/topic_sousrub.aspx?t c=SKIN_SCIENCE_ROOT%5EAN_ORGAN_REVEALED %5ETHE_DERMIS&cur=THE_DERMIS science.com/_int/_en/topic/topic_sousrub.aspx?t c=SKIN_SCIENCE_ROOT%5EAN_ORGAN_REVEALED %5ETHE_DERMIS&cur=THE_DERMIS 