The organs of the integumentary system include
the skin and its accessory structures including hair, nails, and glands, as well as blood vessels, muscles and nerves
Dermatology is what?
The medical specialty for the diagnosis and treatment of disorders of the integumentary system.
Clinical term for "skin"
Where is skin the thickest?
Where is skin the thinnest?
Outer, thinner layer of skin is called ?
What is the Epidermis made of?
What is the "dermis"?
inner, thicker layer of skin
What lies beneath the dermis?
A subcutaneous (subQ) layer (also called hypodermis) which attaches the skin to the underlying tissues and organs.
What is the epidermis made of?
The epidermis is composed of keratinized stratified squamous epithelium
What are the 4 major types of cells in the epidermis?
What do Merkel cells do?
function in the sensation of touch along with the adjacent tactile discs
What do Langerhans cells do?
involved in immune responses, arise from red bone marrow
What do Melanocytes do?
produce the pigment melanin that protects against damage by ultraviolet radiation
What do Keratinocytes do?
(90% of the cells) produce keratin which is a tough fibrous protein that provides protection
I.D. the cell
ID the cell
ID the cell
ID the cell
List the layers of the epidermis.
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
composed of many sublayers of flat, dead keratinocytes called that are continuously shed and replaced by cells from deeper strata; constant friction can stimulate formation of a callus.
where continuous cell division occurs which produces all the other layers
8-10 layers of keratinocytes
comprised of keratinocytes with lamellar granules
present only in thick skin (the skin of the fingertips, palms, and soles)
What is Keratinization?
The accumulation of more and more protective keratin, occurs as cells move from the deepest layer to the surface layer
ID the Layers Top to Bottom.
•Deepest single layer of cells
•Called stratum germinativum
- •Combination of merkel cells, melanocytes, keratinocytes &
- stem cells that divide repeatedly
- •Cells attached to each other & to
- basement membrane by desmosomes & hemidesmosomes
•8 to 10 cell layers held together by desmosomes
- •During slide preparation, cells shrink
- and look spiny
- •Melanin taken in by phagocytosis from
- nearby melanocytes
•3 - 5 layers of flat dying cells
•Show nuclear degeneration
•Contain dark-staining granules
- •Contain lamellar granules that release
- lipid that repels water
- •Seen in thick skin on palms & soles
- of feet
- •Three to five layers of clear, flat,
- dead cells
•Contains precursor of keratin
- •25 to 30 layers of flat dead cells
- filled with keratin and surrounded by lipids
- •Barrier to light, heat, water,
- chemicals & bacteria
•Friction stimulates callus formation
What produces keratinocytes?
Stem cells divide to produce keratinocytes
This is composed of connective tissue containing collagen and elastic fibers
What are the 2 layers of the dermis?
- •the outer papillary region consists of areolar connective tissue containing thin collagen and elastic fibers, dermal papillae, corpuscles of touch and free nerve endings
- •The deeper reticular region consists of dense irregular connective tissue containing collagen and elastic fibers adipose cells, hair follicles, nerves, sebaceous (oil) glands, and sudoriferous (sweat) glands
can appear if the skin is stretched too
Striae or stretch marks
Finger like projections called dermal
papillae create fingerpints.
What are the functions of the papillary region?
–anchors epidermis to dermis
- –contains capillaries that feed
- –contains Meissner’s
- corpuscles (touch) & free nerve endings (pain and temperature)
•Dense irregular connective tissue
•Contains interlacing collagen and
•Packed with oil glands, sweat gland
ducts, fat & hair follicles
•Provides strength, extensibility &
elasticity to skin
–stretch marks are dermal tears from
Reticular Region of the dermis
What do Epidermal ridges do?
reflect contours of the underlying dermal papillae and form the basis for fingerprints (and footprints); their function is to increase firmness of grip by increasing friction.
Variations in skin color arise from variations in the amounts of three pigments:
melanin, carotene, and hemoglobin
Where is Melanin located and how is it produced?-
- produced by melanocytes (located
- mostly in the epidermis, where it absorbs UV radiation)
Why are people different colors?
differences in skin color is due to the amount of pigment produced
What is Carotene?
Hemoglobin - red color (located in erythrocytes
yellow-orange pigment (found in the stratum corneum, dermis, and subcutaneous layer)
is not part of the skin but, among its
functions, it attaches the skin to the underlying tissues and organs
Subcutaneous (subQ) layer
contains lamellated (pacinian) corpuscles which
detect external pressure applied to the skin.
Hair is composed of what?
dead, keratinized epidermal cells
What are the parts of the pillie (hair)?
•root which penetrates into the dermis
•epithelial root sheath
•dermal root sheath
What are the functions of hair?
•Prevents heat loss
•Eyelashes help protect eyes
- •Touch receptors (hair root plexus)
- senses light touch
Name the glands of the skin.
•Sebaceous (oil) glands
- •Sudoriferous (sweat)
•Mammary (milk) glands
Sebum does what?
- –combination of cholesterol, proteins,
- fats & salts
–keeps hair and skin soft & pliable
- –inhibits growth of bacteria &
What are the 2 types of sweat glands?
These are found in most areas of skin contain a secretory portion in dermis with duct to surface and regulate body temperature with perspiration
Eccrine (sweat) glands
These are found in the armpit and pubic region contain secretory portion in dermis with duct that opens onto hair follicle and secretions more viscous
Apocrine (sweat) glands
Where would you find Ceruminous Glands?
What are nails?
Tightly packed, keratinized cells
ID the more prominent features from L-R
- Nail Root
- Nail Bed
- Free Edge
- Nail Matrix
What are the general functions of skin?
•Regulation of body temperature
•Protection as physical barrier
•Excretion and absorption
•Synthesis of vitamin D
How does skin aid in thermoregulation?
•Releasing of sweat onto the skin
- Adjusting flow of blood to the body
- Shivering and constriction of surface
How does the skin provide protection?
- –tight cell junctions prevent bacterial
–lipids released retard evaporation
- –pigment protects somewhat against UV
- –langerhans cells
- alert immune system
True or False?
Lipid soluble substances can be absorbed through the skin
What are 3 most common types of skin cancer?
–basal cell carcinoma (rarely metastasize)
- –squamous cell
- carcinoma (may metastasize)
–malignant melanomas (metastasize rapidly)