The integumentary system consists of the skin, hair, nails, and skin glands. The skin is composed of two principal layers - the epidermis and dermis. The epidermis is made up of stratified squamous epithelium and provides a protective barrier. The dermis lies below the epidermis and contains collagen, elastic fibers, and vasculature that provide strength and nourishment to the skin. Skin appendages include hair follicles, sebaceous glands, sweat glands, and nails. The skin regulates body temperature, protects the body, and plays a role in sensation and immune function.

1. THE INTEGUMENTARY
SYSTEM
Chona Araga, M.D.

2. COMPOSED OF:
• 1. SKIN
• Heaviest, largest single organ
• 2.SKIN APPENDAGES:
A.sweat gland
B. sebaceous gland
C. hairs
D. nails

4. SKIN called integument
• - also
• - simply means covering
• FUNCTIONS:
5. Keeps water and other precious molecules in
the body
6. Keeps water out
7. Protects the body from external agent
8. Insulates and cushions deeper body organs
9. Protects body from mechanical, chemical,
thermal damage and also bacteria

5. FUNCTIONS
• 6. Regulates heat loss from body surface
• 7. Acts as mini-excretory system, urea, salt,
water are lost when we sweat
• 8. Manufactures several proteins important to
immunity
• 9. Storage of Vitamin D precursor
• 10. Contains cutaneous receptors that serve as
sensors for touch, pressure, temperature
and pain

6. 2 PRINCIPAL LAYERS
• 1. EPIDERMIS
• 2. DERMIS

7. EPIDERMIS
• Superficial protective layer of the skin
• avascular
• Composed of Stratified Squamous Keratinized
Epithelium that varies in thickness
• All but the deepest layers of epidermis are
composed of dead cells
• Composed of 4-5 layers, depending on its
location within the body
• Palms and soles have five layers because these
areas are exposed to most friction

8. • Composed of keratinocytes,nonkeratinocytes
melanocytes, Langerhans cells and Merkel’s
cells
• Constantly being regenerated every 20-30 days
• Sequence of cytological changes of
keratinocytes is referred to as cytomorphosis
• Overlies projection of the dermis (dermal
papillae), forming series of epidermal ridges
• On the fingertips are visible as finger prints

9. 1. Stratum Basale (germinativum)
• Deepest layer
• Composed of single layer of cells in contact
with the dermis
• Cells are cuboidal to columnar keratinocytes
• Mitotically active
• Source of cells replacing the shed off superficial
layers
• Attached directly to the basal lamina by
hemidesmosomes
• Contains melanocytes and Merkel’s cells

13. Stratum Spinosum
• Few layers of mitotically active polyhedral
keratinocytes (prickle cell) which have
extensions termed intercellular bridges now
known to terminate in desmosomes
• Also contains Langerhan’s cells
• Part of Malphigian layer(stratum malphigii) :
stratum spinosum and stratum basale
• Upper aspect of this layer are keratinocytes
containing membrane coating granules
– Granules are released into intercellular space in
the form of lipid containing sheets impermeable
to water and foreign substances

15. Stratum Granulosum
- Consists of only 3-4 flattened rows
of keratinocytes that contain
keratohyaline granules, bundles of
keratin filaments and occassional
monochromatic granules

17. Stratum Lucidum (Clear layer)
4-6 rows of very thin, pale-staining,
eosinophilic cells
• Nuclei,organelles,and cell
membranes are no longer visible so
this layer appears clear
• Exists only in the lips and the thickened
skin of soles & palms
• Contains a transluscent substance called
eleidin

19. Stratum Corneum
• 15-20 layers of flattened, scale-like anucleated
cells, which arecontinuously shed as flake-like
residues of cells
• This surface layer is cornified and is the real
protective layer of the skin
• Cornification is brought on by keratinization and
the hardening , flattening process that takes place
as the cells die and are pushed to the surface
• Friction at the surface of skin stimulates additional
mitotic activity of stratum basale, resulting in the
formation of a callus for additional protection
• Continuously sheds cells by a process termed
desquamation

21. Non keratinocytes in epidermis:
1. Melanocytes- present in S. basale
- synthesize the pigment melanin
providing a protective barrier to UV
radiation in sunlight
2. Langerhan’s cell
- located primarily in S. spinosum
- possess long process (ddendritic cells),
originate from monocytes
- contain characteristic paddle-shaped
Birbeck granules
- antigen presenting cells

22. c) Tactile cells ( Merkel cell)
- present in small number in
S. basale
- possess desmosomes and keratin
filaments
- pale cytoplasm containing small,
dense-cored granules
- aid in tactile (touch) reception

23. COLORATION OF SKIN
• . CAUSED BY EXPRESSION OF A
COMBINATION OF 3 PIGMENTS
3.MELANIN
4.CAROTENE
5.HEMOGLOBIN

24. MELANIN
• Brown-black pigment produced by the
melanocytes of stratum basale
• Guards skin against damaging effect of UV
rays of sunlight
• Gradual exposure to sunlight promotes
increased production of melanin; hence
tanning of skin
• In albino, there is a normal number of
melanocytes but lacks enzyme tyrosinase, that
converts the amino acid tyrosine to melanin

26. • “freckles”- caused by aggregated patch of
melanin
“vitiligo”- lack of melanocytes in localized areas
of the skin causing distinct white spots
2. CAROTENE
- a yellowish pigment found in epidermal cells
&
fatty parts of dermis
- abundant in skin of Asians
- together with melanin, accounts for the
yellowish-tan color of Asians

28. 3. HEMOGLOBIN
• Not a pigment of the skin, rather it is
the oxygen-binding pigment found in
RBc
• Oxygenated blood flowing through
the dermis gives the skin its pinkish
tones

29. DERMIS
• Deeper and thicker than the epidermis
• A strong and stretchy envelope that helps to
hold the body together
• Blood vessels within the dermis nourish the
living portion of the epidermis
• With numerous collagenous, elastic and
reticular fibers that give support to the skin
• Highly vascular and glandular
• Contains many nerve endings and hair follicles

30. Layers of Dermis
1. PAPILLARY LAYER
- in contact with epidermis
- Accounts for about 1/5 of the entire
dermis
- With numerous projections called Dermal
Papillae, that extend from the upper portion
of the dermis into the epidermis
- Dermal papillae contain capillary loops,
which furnish nutients to the epidermis

31. - Some papillae house pain
receptors (free nerve
endings) and touch receptors
(meissner’s corpuscles)
- Dermal papillae form the
base for the friction ridges
on the fingers and toes

32. • Reticular layer
– Deepest skin layer
– Contains blood vessels, sweat & oil
glands, and deep pressure receptors
(Pacinian Corpuscles)
– Many phagocytes are found here;
they engulf bacteria that have
managed to get through the
epidermis
– May contain Pacinian corpuscles and
Krause’s end bulbs

33. Thick and Thin Skin
Thick skin (glabrous Thin skin (hairy skin)
skin) 75-100 um thick
• 400-600um thick Less prominent
• Prominent corneum lacks
S.corneum,well granulosum and
developed S. lucidum
granulosum and With hair follicles
distinct S. lucidum sebaceous glands
• Lacks hair and arrector pili
follicles,sebaceous
glands and arrector
pili

34. SURFACE PATTERNS
• 1. CONGENITAL PATTERNS
+ fingerprints or friction ridges
- present on palms and soles
- formed by the pull of elastic fibers
within the dermis
- function to prevent slippage when
grasping objects

35. 2. ACQUIRED LINES
• Deep Flexion Creases
- found on the palms
Shallow Flexion Lines
- seen on knuckles and surface of other joints
Furrows in the forehead and face (wrinkles)
- acquired from continual contraction of facial
muscles, such as from smiling or squinting in
bright light or against the wind; facial lines
become more strongly delineated as one ages

38. LANGER LINES
Lines of tension produced by the orientation
of collagen and elastic fibers in nonrandom
pattern of arrangement
Linear wound oriented parallel to langer lines
tend to close and heal with minimum
scarring, even if left unsutured
Linear wounds oriented perpendicular to
langer lines tend to gape and heal slowly
with consipicuous scarring if left unsutured

43. • Beneath the dermis lies the hypodermis
(Gr. hypo, under, + derma, skin), or
subcutaneous tissue, a loose connective
tissue that may contain a pad of adipose
cells, the panniculus adiposus.
• The hypodermis, which is not considered
part of the skin, binds skin loosely to the
subjacent tissues and corresponds to the
superficial fascia of gross anatomy.

45. CUTANEOUS GLANDS
• 1. SEBACEOUS (OIL) GLANDS
- found all over the skin, except on palms and
soles
- ducts usually empty into a hair follicle but
some open directly onto skin surface
- secretion is called sebum, a mixture of oily
substance and fragmented cells that keep
skin
soft and moist and prevents hair from
becoming brittle

46. • - if the drainage pathway for sebaceous
glands becomes blocked for some reason,
the glands may become infected, resulting
in acne
• - sebum also contains chemicals that kill
bacteria
• - become very active when sex hormones
are produced in increased amounts during
adolescence, thus skin is oilier during this
period of life

48. • SWEAT GLANDS
- also called sudoriferous glands
- widely distributed in the skin; numerous in
palms, soles, axillary and pubic regions
- secretion evaporates and cools in the body
6 TYPES:
1. Eccrine
2. Apocrine

49. ECCRINE SWEAT GLAND
• - more numerous and found all over the
body especially in forehead, back, palms
and soles
• Innervated by cholinergic fibers
• Secretion reaches skin surface via a duct
that opens directly on surface of skin
through sweat pores
• Secretion is mostly water with few salts

50. Secretory unit composed of:
• 1. dark cells – secrete mucus-rich material
• 2. clear cells – secrete a watery,
electrolyte rich material
• 3. myoepithelial cells – contract and aid
nin expressing the gland’s secretion into
the duct
• Ductal unit is narrow and lined by
stratified cuboidal epithelium

51. 2. APOCRINE SWEAT GLANDS
• - much larger, localized gland found in axillary
and pubic regions where they secrete into
hair follicles
• Not functional until puberty
• Responsive to hormonal influence
• Secretion is thick and rich in organic
substances which is odorless when released
but quickly broken down by bacteria into
substances responsible for body odor
• Innervated by adrenergic fibers

54. MAMMARY GLAND
• Found within the breasts
• Specialized sudoriferous or sweat
gland that secrete milk during
lactation
• Under the stimulus of pituitary
gland

55. ADIPOSE

56. HAIR
• An invagination of the epidermis
• Characteristic of all mammals, but its
distribution, function, density and texture varies
across mammalian species
• Humans are relatively hairless, with only the
scalp, face, pubis & axilla being densely haired
• Men with more obvious hair because of the
male hormone
• Certain regions of body are hairless like the
palms, soles, lips, nipples, penis,labia minore
• Lifespan 3-4 mos for eyelashes, 3-4 yrs-scalp

57. Primary Function of Hair: Protection
e.g. scalp hair, eyebrows- protect
from sunlight

58. • PARTS OF HAIR:
1. Shaft – the visible but dead portion of
hair projeting above surface of the skin
• Consists of medulla,cortex and cuticle
• 2. Root – enclosed in the follicle
• 3. Bulb – terminal expanded region in
which hair is rooted
• Deeply indented by a dermal papilla
which contains capillary loops for
nutrition
• Contains cells that form internal root
sheath and medulla

59. • 1. Internal root sheath – deep to the
entrance of sebaceous glands
• Composed of Henle’s layer, Huxley’s layer
and cuticle
• 2. External root sheath
• - direct continuation of the S. malphigii
• Glassy membrane – noncellular layer
• Separates the hair follicle from the
surrounding dermal sheath

61. 3 DISTINCT KINDS OF HAIR IN
HUMANS
• 1. LANUGO –
- fine, silky fetal hair that appears during
the last trimester of development
- Usually not evident on a baby at birth
unless it has been born prematurely
2. ANGORA
- grows continuously in length, as on scalp
and on face of males

62. • 3. DEFINITIVE
- grows to a certain length and then ceases to
grow
- most dominant type of hair
e.g. eyelashes, eyebrow,pubic, and axillary hair
- A sebaceous gland and an arrector pili muscle
are attached to the hair follicle
- When the muscle involuntarily contracts due to
thermal or psychological stimuli, the hair follicle
is pulled into an upright position, causing the
hair to”stand on its end” and producing
goosebumps

64. NAILS
• Found on distal dorsum of each fingers and
toes
- Forms from a hardened, transparent, stratum
corneum of epidermis
- Consists of:
- Nail Body
- visible attached portion
- Nail Root
- part of the nail covered by skin

65. Nail Bed
- where nail root and nail body
are attached
Free edge
- the distal exposed border
attached to undersurface of
hyponychium
Hyponychium
- beneath the free edge

66. Eponychium ( Cuticle)
- covers the nail root
- frequently splits causing a
hangnail
Nail Matrix
- proximal part of the nail bed
- growth area of the nail
Lunula
-whitish crescent (half moon)
shaped area at the
proximal aspect of nail

67. -Fingernails grow at
approximately 1 mm per week
- Growth of toenails is slower
- nails are transparent and
nearly colorless but they look
pink because of the rich blood
supply in the underlying
dermis

69. Thank You