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
3 Layers of your Skin
1. EpidermisOutermost covering Epithelial cellsAvascular
2. Dermis True skinConnective tissueVascular
3. Subcutaneous tissue
EPIDERMIS Thickness varies on location
*thinnest on eyelids
*thickest on palms of hands & soles of feet.
EPIDERMIS
4 cell types
1. 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
1. Stratum Germinativum (deepest)
2. Stratum Spinosum
3. Stratum Granulosum (keratinization begins & cells die)
4. Stratum Lucidum
5. 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.
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.
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)
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”
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