3. Epidermis
Outermost layer of the skin
Comprised of epithelial cells
Contains no blood vessels (avascular)
Nutrients diffuse over from dermal blood vessels
Is thicker in areas of significant wear and tear
(palms of hands and soles of feet)
Keratin
Protein that replaces epidermal cell cytoplasm in
order to thicken and protect the skin
Also comprises hair and nails
7. Epidermal Cells
Keratinocytes
Major epidermal cell type
~28 day transit time from stratum basale to stratum corneum
Melanocytes
Scattered between cells of stratum basale
Contain organelles called melanosomes, in which the melanin
pigment is synthesized
Melanosomes are quickly released and phagocytized by
neighboring keratinocytes (epidermal melanocytes do not retain
their melanosomes)
Langerhans cell – involved in immune response
Merkel cell – touch receptor
10. Dermis
Comprised of elastic connective tissue
Allows for skin to stretch
Contains blood vessels (vascular) and nerves
(innervated)
Location of accessory structures (sweat glands,
oil glands, and hair)
Dermal papillae
Extensions of dermis into epidermal layer
Are what form fingerprints
13. Hypodermis
aka, subcutaneous layer
NOT part of the skin
Connects skin to surface muscles
Consists of loose connective tissue and fat
(adipose) tissue
14.
15. Burns
1st Degree (aka, superficial
partial-thickness)
Epidermis and possibly a
portion of dermis
Tissue is reddened and may
blister
2nd Degree (aka, deep partial-
thickness)
Epidermis and portions of
dermis
Tissue is blistered and broken
3rd Degree (aka, full-thickness)
Full skin and possibly
subcutaneous tissue
Tissue is broken, dry and
pale, or charred
Rule of Nines – estimate % of body
surface area in treatment of
burns
17. Sebaceous (Oil) Glands
Sebum – oily secretion
Lubricates skin and coats hair
Prevents drying
It is believed that bacterial lipases break down
triglycerides of sebum into irritative fatty acids that cause
acne.
Ducts open into hair follicles
Meibomian glands
Modified sebaceous glands
Lubricate eyes
18.
19.
20. Questions to answer (place on separate
paper and turn them in on the way out)
1) Why is a third degree burn so much more
devastating than a first degree burn?
(Answer based on the specific skin layers
and structures involved.)
2) Why does washing your hair actually
damage it? How do we treat this
damage?
22. Sudoriferous (Sweat) Glands
Cool the body via evaporation
Eccrine Sweat Glands
Distributed over entire body except lips and parts
of external genitalia
Ducts open directly onto surface of skin
Excrete salts, urea, ammonia, and uric acid
along with water
23.
24.
25. Sudoriferous (Sweat) Glands (cont.)
Apocrine Sweat Glands
Located in armpits (axillae), nipples, and groin area
Duct empties into hair follicle superficial to sebaceous
gland
Become active at puberty
Secretion is initially odorless; bacteria on the skin
metabolize secretory products to produce malodorous
compounds
Secrete in response to emotional stimuli (not heat)
Modified apocrine sweat glands
Ceruminous glands – ear canal; produce cerumen (ear wax)
Ciliary glands - eyelids
Mammary glands – produce milk (breasts)
26.
27. Hair
Two types in adults
Vellus hairs – thin, short and poorly pigmented
Terminal hairs – thicker, longer and more heavily
pigmented
Composed mainly of “hard keratin” (as opposed
to “soft keratin” in the epidermal cells)
Arrector pili muscle causes hair to raise, forming
goose bumps
Hair color is determined by relative amounts of
eumelanin (black/brown) & pheomelanin
(reddish color)
28. Hair (cont.)
Shaft – portion of hair above the skin
Root – portion of hair below the skin
Follicle – sheath of epithelial and connective tissue that
surrounds the hair
Bulb – located at base of follicle
Three phases in life cycle of each hair
Anagen – the period of active growth (0.04 cm per day)
Catagen – the period of involution (degeneration) when the
lower part of the follicle below the arrector pili muscle atrophies
Telogen – the resting period between the end of follicular
atrophy and the shedding of the hair
30. Nails
Comprised of hard keratin from stratum corneum
Nail plate – hard portion of nail
Nail bed
Comprised of stratum basale and stratum spinosum
Nail plate rests on the nail bed
Nail root – proximal part of nail (covered by skin)
Nail matrix – contains stem cells that cause nail to
grow
32. Functions of Skin
Protect against infection
Protect against dehydration
Membrane-coating granules (MCG’s) seal spaces between
keratinocytes to prevent entry of pathogens and loss of water
Regulate body temperature
Vasoconstriction (blood vessels become narrower) – conserve
heat
Vasodilation (blood vessels open wider) – promotes
radiation/dissipation of heat to surrounding air
Sweat
Sensory reception
Pain
Temperature changes
Touch (and pressure)
33. Skin Discoloration
Albinism – lack of melanin production due
to genetic mutation
Cyanosis – bluish skin color due to
decreased O2 in blood
Jaundice – excessive bile pigments
(bilirubin) in the blood causes skin to turn
yellow in color
36. Skin Disorders
Dermatitis (aka, eczema)
Inflammation of the skin
Due to irritants such as oil of poison oak or
poison ivy, detergents, acids, etc.
Atopic Dermatitis
Intense itching
Skin inflammation
Crusting of skin surface
38. Skin Disorders (cont.)
Psoriasis
Faster than normal renewal of cells resulting in
accumulation of cells in the stratum corneum
Produces red (erythematous), flat areas
(plaques) covered with silvery scales
Unknown etiology (cause)
42. Skin Disorders (cont.)
Wart (aka, verruca)
Small tumor
Caused by viruses of
the human
papillomavirus (HPV)
family
Notas del editor
Childs, Gwen V. “Skin.” University of Texas Medical Branch: Cell Biology Graduate Program. 2002. The University of Texas Medical Branch. 10 July 2008 <http://cellbio.utmb.edu/microanatomy/skin/skin_and_mammary_glands.htm>.
Childs, Gwen V. “Skin.” University of Texas Medical Branch: Cell Biology Graduate Program. 2002. The University of Texas Medical Branch. 10 July 2008 <http://cellbio.utmb.edu/microanatomy/skin/skin_and_mammary_glands.htm>.
Hale, Laura P. “Introduction to Systemic Histology.” Duke University. 10 July 2008 <http://pathology.mc.duke.edu/research/PTH225.html>.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Cohen, Barbara J. Memmler’s The Human Body in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2005.
Cohen, Barbara J. Memmler’s The Human Body in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2005.
Cohen, Barbara J. Memmler’s The Human Body in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2005.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Cohen, Barbara J. Memmler’s The Human Body in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2005.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Cohen, Barbara J. Memmler’s The Human Body in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2005.
Slomianka, Lutz. “Blue Histology – Integumentary System.” School of Anatomy and Human Biology – The University of Western Australia. 2006. 10 July 2008 <http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm>.
Cohen, Barbara J. Memmler’s The Human Body in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2005.