HS1 integumentary system

7 Functions 1. Protection 2. Regulates body temperature 3. Manufactures Vitamin D 4. Sensory perception 5. Temporary storage of fat, glucose, water and salts 6. Screens out harmful ultraviolet radiation 7. Absorbs certain drugs

Layers of your Skin

3 Layers of your Skin 1. Epidermis 2. Dermis 3. Subcutaneous tissue Outermost covering Epithelial cells Avascular 2. Dermis True skin Connective tissue Vascular 3. Subcutaneous tissue

Layers broken down….

Layers of the Skin Epidermis

EPIDERMIS Thickness varies on location *thinnest on eyelids *thickest on palms of hands & soles of feet.

EPIDERMIS 4 cell types Keratinocytes produces keratin which keeps skin dry and is a barrier to UV & bacteria 2. Merkel Cells Sensory receptors for touch 3. Melanocytes Make protein “melanin” – give you your color. The more melanin the darker you are Freckles = patches of melanin 4. Langerhans Cells defend microorganisms

Epidermis cont… 5 layers Stratum Germinativum (deepest) Stratum Spinosum Stratum Granulosum (keratinization begins & cells die) Stratum Lucidum Stratum Corneum

Epidermis cont… Lower edge of layer #1 has ridges known as “papillae” - very pronounced in fingers/soles/palms -provide resistance to slipping for holding/grasping objects -create individual fingerprints & footprints.

Layers of the Skin Cont…. Dermis

Dermis Consists of Connective Tissue Collagen tissue bands Elastic fibers Nerve endings Muscles Hair follicles Oil & sweat glands Fat Cells Thickest over soles of feet & palms of hands

Dermis cont… Contains nerve receptors • Sensory nerves – heat, cold, touch, pain and pressure • Touch receptors close to the surface • Pressure receptors are deeper Blood vessels in dermis aid in the regulation of body temp. An or in outside temp makes blood vessels dilate to bring warmed blood flow to the surface of your body.

Layers of the Skin Cont… *Subcutaneous

Subcutaneous Also called “Superficial fascia” or “Hypodermal” Layer Not a true part of integumentary system (attaches dermis to surface muscles)

Subcutaneous Consists of loose connective tissue Contains ½ of body's stored fat. Some injections can be given here (abbreviated SQ – given at 45 degree angle)

Appendages of the Skin Includes Hair, Nails, Sweat Glands, & Oil Glands

Appendages of the Skin Hair

Hair Almost everywhere on the body (except palms, soles, glans penis, & inner vaginal labia) Length, thickness, type and color varies

Hair Length, thickness, type and color varies Outer layer = CORTEX (as one ages, pigment replaced with air and looks white/gray) Inner layer = MEDULLA Part under the skin = ROOT Part outside the skin = SHAFT (protects skin surface)

Hair cont… FOLLICLE = pocket in epidermis, hair inside (determines straight or curly hair) PAPILLA = tuft of tissue in root, contains capillaries ARRECTOR PILI MUSCLE = attached on side of each follicle, when stimulated by a sudden chill it contracts and causes skin to pucker “Goosebumps”

Appendages of Skin Nails

Nails Formed in the nail bed “matrix” Epidermal cells fuse together and fill with keratin

Sweat Glands “SUDORIFEROUS GLANDS” Appendages of Skin Sweat Glands “SUDORIFEROUS GLANDS”

Sweat Glands Perspiration = sweat (99% water) Distributed over the entire skin surface Large numbers under the arms, palms of hands, soles of feet and forehead

Sweat Glands Duct extends to form a pore in the skin, perspiration excreted through the pores May be activated by heat, pain, fever and nervousness Average fluid loss is 500 ml per day

Oil Glands “Sebaceous Glands” Appendages of Skin Oil Glands “Sebaceous Glands”

Oil glands Secret oil (SEBUM) that protects and lubricates the skin Keeps skin soft & pliable