This document provides an overview of the integumentary system, which consists of the skin and its accessory structures like hair, glands and nails. It describes the structure and layers of the skin, including the epidermis and dermis. It details the functions of skin like protection, sensation, regulation and secretion. It discusses the cells and layers that make up the epidermis, as well as the structures in the dermis. The document also reviews skin appendages such as hair, nails and glands, and describes wound healing and scar formation.

1. Integumentary System
S.S.MOORTHY SEMENCHALAM
M.Sc. Comm Health (Occ Health) UKM
B.HSc. Nursing (Aust)
Dip Med Sc. (Moh)
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2. Learning Outcomes
After completing this system, students should be able to:
i. Identify the functions of skin
ii. List the layers of epidermis and cells that compose them
iii. State the composition of papillary & reticular layers of dermis
iv. Discuss the structure & functions of skin appendages (hair, glands
and nail)
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3. INTEGUMENTARY SYSTEM
• consists of skin & its accessory structures
(inc. glands, hair & nails)
• SKIN - cutaneous membrane
- covers external surface of body
- largest organ
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4. SKIN FUNCTIONS
• protection - against invasion of
microorganisms, water loss and dehydration.
• defense - contains macrophages, lymph nodes
and other structures which identify pathogens
and provide first line of defense against them.
• sensation - the skin contains sense organs for
light touch, pressure, temperature, and pain.
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5. Cont.
• secretion - the skin secretes the precursor to
Vitamin D (this is then activated by processing
in the liver and kidney), and melanin.
• thermoregulation - by diverting blood into or
away from the skin the body can release or
conserve heat.
• excretion – small amount of waste are lost
through the skin
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6. STRUCTURE OF THE SKIN
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7. The layers/ strata of the skin….
EPIDERMIS
 superficial
 thinner portion of epithelial tissue
DERMIS
connective tissue
 deeper, thicker
SUBCUTANEOUS LAYER
adipose & areolar tissue
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8. SUBCUTANEOUS
TISSUE
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9. EPIDERMIS
- contains 4 principal types of cell
 Keratinocytes
 Melanocytes
 Langerhan’s cells
 Merkel cells
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10.  Keratinocytes
• arranged in 4-5 layers
• 90% of epidermal cells
• Produce:
(i) Protein keratin (tough, fibrous)
- protection
(ii) Lamellar granules
- water-repellant sealant
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11.  Melanocytes
• Produce melanin (brown-black pigment);
contributes to skin color
• Everyone have same number
• shield DNA from being damaged by UV
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12.  Langerhan’s cells
• Originate from bone marrow
• Participate in immune response
• Site of invasion of HIV
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13.  Merkel Cells
• Least numerous
• Deepest layer
• Associated with Merkel (tactile) disc
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14. EPIDERMIS: STRATA
 stratum basale (germinativum)
 stratum spinosum (prickly layer)
 stratum granulosum (granular)
 stratum lucidum (clear layer)
 stratum corneum (horny layer)
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15.  Stratum basale
• deepest layer
• single row of cuboidal/ columnar of actively dividing
keratinocytes
• melanocytes, Langerhan’s cells & Merkel cells
 Stratum spinosum
• 8- 10 layers of keratinocytes
• projections of melanocytes & langerhan’s cells
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16.  Stratum granulosum
• 3-5 layers of flattened keratinocytes that
undergo apoptosis
• degeneration of nuclei and organelles
** apoptosis- genetically programmed cell death
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17.  Stratum lucidum
 present only in skin of fingertips, palms & soles
 3-5 rows of clear, flat, dead keratinocytes
 Stratum corneum
• 25-30 rows of dead, flat keratinocytes
• continously shed & replaced by cells of deeper
layer
• protection against abrasion and penetration
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18. Jan,08
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19. DERMIS
• connective tissue; collagen & elastics fibers
• 2 layers
 Papillary layer
- superficial portion (1/5)
- loose fibers
- contains dermal palpillae that house capillaries, corpuscles of touch &
free nerve endings
 Reticular layer
- deeper portion (4/5)
- dense connective tissue
- spaces between fibers; adipose cells, hair follicles, nerves, sebaceous
glands
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20. SUBCUTANEOUS LAYER
• Subcutaneous tissue
• Deep to dermis
• Storage depot for fat
• Anchors skin to underlying tissue
• Blood vessels & nerves ending: Pacinian
corpuscle (sensitive to pressure)
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21. SKIN COLOR
• 3 pigments
(i) Melanin (pale-yellow-tan-black)
(ii) Carotene (yellow-orange)
- Precursor of Vit. A
- Subcutaneous & fatty area
(iii) Hemoglobin (red)
- O2-carrying pigment
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22. Melanin
• different skin color due to amount of
pigment produce
• freckles: accumulation of melanin
• > UV exposure, > melanin production,
> protective against UV radiation
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23. APPENDAGES OF SKIN
 Hair
 Nail
 Glands
 Sweat glands
 Sebaceous glands
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24. Hair
Functions:
• warmth
• protection (scalp injury, sun)
• shield from foreign particles (e.g. eyelashes)
• filters (nostrils)
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25. Structure of the hair
• Shaft – project from surface
• Root- embedded in dermis
• Bulb- base of root; enclosed in hair
follicle; associated with arrector pili
muscle
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26. Structure of the hair
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27. Free edge
(extend past Nails
distal end)
Nail body  plates of tightly,
(visible portion) packed, hard,
keratinized epidermal
Lunula cells
 clear, solid covering
Eponychium
over dorsal of fingers
(cuticle)
Nail-root (portion;  Protection from
buried in skin fold) trauma
 “Tools”- to grasp and
manipulate
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28. Sweat (Sudoriferous) glands
• everywhere; except nipples & external
genitilia
• types:
a. Eccrine sweat glands
b. Apocrine sweat glands
c. Ceruminous glands
d. Mammary glands
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29. Eccrine sweat glands
• abundant, with odorless secretion
• most numerous (palms, soles, forehead),
originate in subcutaneous layer
• produce sweat (99% water)
• excrete salts, vitamin C, antibodies, metabolic
wastes, lactic acid
• thermoregulation (lower body temperature)
• autonomic nervous system
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30. Apocrine sweat glands
 less numerous, secretions that develop odors
 axillary, groin
 ducts empty into hair follicles
 true sweat and fatty acids
 viscous, milky, bacteria food
 active during puberty
 sympathetic nervous system (pain, stress)
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31. Ceruminous glands
• modified apocrine glands
• secrete cerumen (ear wax)
• external auditory canal
Mammary glands
■ modified sweat glands
■ secrete milk
■ breast
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32. Sebaceous (oil) glands
• groups of specialized epithelial cells
• secrete oil or sebum
• everywhere, except palms & soles
• usually secrete into hair follicles
• lubricates hair and skin
- softens dead cells (pliability)
- slows water loss
- bactericidal
• stimulated by hormones (androgens)
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33. Wound healing
 events that repairs the skin to its normal (or
near-normal) structure & function
 2 kinds (depending on depth of injury):
- EPIDERMAL wound healing
- affects only epidermis
- DEEP wound healing
- penetrates dermis
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34. Scar formation- fibrosis
• Hyperthropic scar
- scar elevated above normal epidermal
surface; but within boundaries of original
wound
• Keloid scar
- extend beyond boundaries into the normal
surrounding tissue
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35. Jan,08
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36. Differences between scar and
normal skin tissue
• Collagen fibers more densely arranged in
scar tissue
• Less blood vessel, unequal number of hairs,
skin gland & sensory structure
• More lighter in color (due to arrangement
of collagen & scarcity of blood vessel)
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37. Thank you….
Questions please!!
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