THE INTEGUMENTARY
SYSTEM
THE SKIN AND ITS ACCESSORY STRUCTURES
VIDEO: SKIN
• http://www.youtube.com/watch?v=fXIcwm1oqQw
Incredible Human Machine – SKIN
10:08 mins
BODY MEMBRANES
• Function of body membranes
• Cover body surfaces
• Line body cavities
• Form protective sheets around organs
• Classified according to tissue types
CLASSIFICATION OF BODY MEMBRANES
• Epithelial membranes
Also called covering and lining membranes
• Cutaneous membranes
• Mucous membranes
• Serous membranes
• Connective tissue membranes
• Synovial membranes
BEGIN NOTES HERE...
CUTANEOUS MEMBRANE
• Cutaneous membrane = skin
• Composed of keratinized stratified
squamous epithelium
• Underlying dermis is mostly dense
connective tissue
• Dry membrane
Cutaneous
membrane
(skin)
(a) Cutaneous membrane (the skin)
covers the body surface.
Figure 4.1a
• Mucosa
MUCOUS MEMBRANES
• Composed of
• Stratified squamous epithelium (mouth, esophagus) OR
• Simple columnar epithelium (rest of digestive tract)
• Underlying dermis = loose connective tissue
(lamina propria)
• “Wet” or moist membranes
• Lines all body cavities that open to the
exterior body surface
• Often adapted for absorption or secretion
Mucosa of
nasal cavity
Mucosa of
mouth
Esophagus
lining
Mucosa of
lung bronchi
(b) Mucous membranes line body cavities
open to the exterior.
Figure 4.1b
• Serosa
SEROUS MEMBRANES
• Composed of:
• Simple squamous epithelium (surface)
• Underlying dermis = thin layer of areolar
connective tissue
• Lines body cavities that are closed to the
exterior of the body
• Occur in pairs
• Visceral layer covers the outside of the organ
• Parietal layer lines a portion of the wall of ventral
body cavity
• Layers separated by serous fluid
secreted by both membranes
• Serous fluid allows organs to slide around.
Outer balloon wall
(comparable to parietal serosa)
Air (comparable to serous cavity)
Inner balloon wall
(comparable to visceral serosa)
(d) A fist thrust into a flaccid balloon demonstrates
the relationship between the parietal and visceral
serous membrane layers.
Figure 4.1d
SEROUS MEMBRANES
• Specific serous membranes
• Peritoneum
• Abdominal cavity
• Pleura
• Around the lungs
• Pericardium
• Around the heart
Parietal
pleura
Visceral
pleura
Parietal
peritoneum
Visceral
peritoneum
Parietal
Visceral
pericardium pericardium
(c) Serous membranes line body cavities
closed to the exterior.
Figure 4.1c
CONNECTIVE TISSUE MEMBRANE
• Synovial membrane
• Composed of connective tissue only
• Line the fibrous capsules surrounding joints
where they provide a smooth suface and
secrete a lubricating fluid.
• Also lie small sacs called bursa and tendons
• Both cushion organs moving against each
other
Ligament
Joint cavity
(contains
synovial fluid)
Articular (hyaline)
cartilage
Fibrous
capsule
Synovial
membrane
Articular
capsule
Figure 4.2
INTEGUMENTARY SYSTEM
• Skin (cutaneous membrane)
• Skin derivatives
• Sweat glands
• Oil glands
• Hair
• Nails
SKIN FUNCTIONS
• Protects deeper tissues from:
1.
2.
3.
4.
5.
6.
Mechanical damage (bumps)
Chemical damage (acids and bases)
Bacterial damage
Ultraviolet radiation (sunlight)
Thermal damage (heat or cold)
Dessication (drying out)
SKIN FUNCTIONS
7. Aids in body heat loss or heat retention as
controlled by the nervous system
8. Aids in excretion of urea and uric acid
9. Synthesizes vitamin D
SKIN STRUCTURE
• Epidermis—outer layer
• Stratified squamous epithelium
• Cornified or keratinized (hardened by
keratin) to prevent water loss
• Avascular
• Most cells are keratinocytes
• Dermis
• Dense connective tissue
FUNCTIONS OF THE
INTEGUMENTARY SYSTEM
• Protection
• Regulate body
temperature
• Cutaneous sensation
• Synthesize Vitamin D
• Blood storage
• Excretion of wastes (sweat)
THE SKIN
• A large organ
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VIDEO
• http://www.youtube.com/watch?v=fXIcwm1oqQw
Incredible Human Machine - SKIN
LAYERS OF SKIN
Epidermis
• The superficial portion of the skin
• Composed of epithelial tissue
Dermis
• The deeper layer of the skin
• Primarily composed of connective
tissue
Hypodermis
(subcutaneous layer)
•
•
•
•
Deep to the dermis
Not a part of the skin
Consists of areolar and adipose tissue
Fat storage, area for blood vessel
passage, and an area of pressure
sensing nerve endings
OVERVIEW OF EPIDERMIS
EPIDERMIS
DERMIS
Stratified squamous epithelium
• avascular (contains no blood vessels)
• 4 types of cells
• 5 distinct strata (layers) of cells
FOUR PRINCIPLE CELLS OF EPIDERMIS
Keratinocytes
• Produce keratin
• KERATIN protects skin and underlying tissue from heat, microbes,
chemicals
 Release lamellar granules which release a lipid waterproof sealant
Melanocytes
• Produce pigment melanin
 melanin contributes to skin color and absorbs damaging ultraviolet rays
(UV rays)
Langerhans cells
• Phagocyte cells that participate in immune response
Merkel cells
• Sensory cells
• Function in the sensation of touch
5 LAYERS OF THE EPIDERMIS
From deepest to most
superficial (bottom to top)
Stratum basale
(also called stratum
germinativum)
Stratum spinosum
Stratum granulosum
Stratum lucidum
(only in palms and soles)
Stratum corneum
STRATUM BASALE
• Deepest single layer of
epidermis
• Include all 4 cell types:
merkel cells,
melanocytes,
keratinocytes &
stem cells
• Cells divide repeatedly
(MITOSIS)
• When this portion of the
epidermis is destroyed,
new skin cannot
regenerate (even
with a skin graft).
STRATUM SPINOSUM
• Provides strength
and
flexibility to the skin
• 8 to 10 cell layers
STRATUM GRANULOSUM
• Transition between the
deeper, metabolically active
strata and the dead cells of
the more superficial strata
• 3-5 layers of flat dying cells
that show nuclear
degeneration
• Contain lamellar granules
that release lipid that repels
water
• Contain dark-staining
keratohyalin granules

keratohyalin converts
into keratin
STRATUM LUCIDUM
• Present only in the
fingers tips, palms of
the hands, and soles
of the feet.
• 3 to 5layers of clear,
flat, dead cells
• Contains precursor of
keratin
STRATUM CORNEUM
• 25 to 30 layers of flat dead
cells
filled with keratin and
surrounded by lipids
• Continuously shed
• Barrier to light, heat, water,
chemicals & bacteria
• Lamellar granules in this
layer
make it water-repellent.
• Where callus, an abnormal
thickening of the
epidermis, is
formed
MNEUMONIC DEVICE
•C
•L
•G
•S
•B
SKIN STRUCTURE
Figure 4.4
DIAGRAM
LEFT SIDE
• Epidermis
• Dermis
• Hypodermis
BOTTOM
• Sweat gland
RIGHT SIDE
• Hair shaft
• Stratum corneum
• Stratum basale
• Sebaceous (oil) gland
• Arrector pili muscle
• Nerve fibers
• Hair follicle
•X
• Fat (adipose tissue)
MELANIN
•
•
•
•
Pigment (melanin) produced by melanocytes
Color is yellow to brown to black
Melanocytes are mostly in the stratum basale
Amount of melanin produced depends upon
genetics and exposure to sunlight
• Skin with too much melanin is called hyperpigmented skin.
• Skin with too little melanin is called hypopigmented skin.
DERMIS
• Strong, flexible connective tissue
• Heavily embedded with collagen, elastin, reticular
fibers
• Binds the entire body together like a body stocking.
(Like an animal “hide”.)
• Richly supplied with nerve fibers, blood vessels, and
lymphatic vessels.
• Contain: hair follicles, oil & sweat glands
DERMIS
• Two layers
1. Papillary layer (thin, superficial layer =
20%)
• Projections called dermal papillae
• Pain receptors
• Capillary loops
• EPIDERMAL RIDGES form on palms of
hands and soles of feet
• increase friction and enhance
gripping
• Form FINGERPRINTS
2. RETICULAR LAYER
• (80% thickness)
• Contain; blood vessels, glands, nerve
receptors
• Bundles of collagen fibers form cleavage
lines (Appear as fine lines on the skin.)
• Surgery: incisions parallel, not
perpendicular
• No skin gapes; heals faster
• Collagen & Elastin: give skin resiliency,
flexibility and bind to water to keep skin
hydrated.
• Flexure lines (deep folds) @ joints (wrists,
fingers, soles, toes)
FINGERPRINTS
There are three basic fingerprint
patterns and seven subgroups.
1.Arch
2.Whorl
3.Loop
FINGERPRINTS
• A fingerprint is an impression of the friction ridges
found on the inner surface of a finger or a thumb.
• Friction ridges are also found on the palms of the
hands and on the soles and toes of your feet.
Fingerprints are formed while a baby is still in the
womb.
• You cannot get rid of your fingerprints – you also
cannot change them, unless you do something drastic
such as chopping off a finger.
FINGERPRINTS
• Every person’s fingerprint is unique. Not even identical
twins have the same fingerprints. No two fingerprints
have ever been found to be identical.
• Secretions from the eccrine (sweat) glands can leave
impressions on smooth surfaces, such as glass, plastic,
and polished wood.
• A special type of powder is used to ‘lift’ fingerprints
from such surfaces for purposes of identification.
FINGERPRINTS
• A Frenchman, pioneered the use of physical
evidence to solve crimes. The date was 1812.
• Fingerprinting is the most commonly used forensic
evidence worldwide. It is claimed to do better than
DNA testing to identify murderers, rapists and other
serious offenders, especially in countries where DNA
testing is not widely used.
TATTOOS
TATTOOS
TATTOOS
• Tattooing is a permanent coloration of the skin in which
a foreign pigment is injected into the dermis.
• When first injected into the skin, tattoo ink spreads from the
puncture site to both the epidermis and the dermis. And as your
tattoo heals, immune cells or phagocytes in the epidermis engulf
the ink and epidermal cells flake off, carrying ink away.
• The dermis also contains cells involved in immune responses and
that recognize the tattoo ink as foreign. Tattoo ink is trapped in
the dermis in a meshwork of fibroblast cells and collagen that
form granular tissue.
• If a tattoo is done properly, tattoo ink won't reach the hypodermis.
As you get much older, the tattoo pigment may migrate deeper
into the dermis (that's why your tattoo may fade a bit over time),
but for the most part, it remains at the upper portion of the dermis,
closer to the epidermis.
SKIN COLOR
• Melanin
• Yellow, brown or black pigments
• Carotene
• Orange-yellow pigment from some
vegetables
• Hemoglobin
• Red coloring from blood cells in dermis
capillaries
• Oxygen content determines the extent
of red coloring
HOMEOSTATIC IMBALANCES
• Choose ONE homeostatic imbalance in
chapter 4. Look for the balance icon
and red heading.
• Read about it.
• Write a short summary in your notebook, identifying
the name, cause, and appearance (if listed).
• Use heading:
• “HOMEOSTATIC IMBALANCE OF THE
INTEGUMENTARY SYSTEM”