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INTEGUMENTARY SYSTEM
Cutaneous membrane
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Skin
Largest organ
Covers an area of about 2 square meters
Weighs 4.5 to 5 kg
Serves as a barrier
1st line of defense for you body
SKIN
• Skin is our protective covering.
• It has 2 names
– Integument
– Integumentary system
Integumentary system
• Formed by the skin and its derivatives
– Sweat glands
– Oil glands
– Hair
– nails
Factoids
• You will shed about 40 pounds of skin in a
lifetime
• There are over a million dust mites,
microscopic organisms on you mattress
and pillow eating the dead skin cells you
shed during the night.
Factoids
• Skin must be cleaned regularly or it will
become cracked or inflamed.
• Dead cells along with the dead skin cells
are a food source for bacteria called a
slurry. This slurry will emit a foul smell.
• As you age, skin becomes thinner and is
easily damaged. It will sag due to loss of
elasticity.
INTERESTING FACTS
• A human loses an average of 40 to 100
strand of hair a day.
• A fetus acquires fingerprints at the age of
3 months
• Every person has a unique tongue print.
• An average human scalp has 100,000
hairs.
• By the age of 60, most people have lost ½
of their taste buds.
• Every square inch of human skin consists
of 20 feet of blood vessels.
• Every square inch of the human body has
an average of 32 million bacteria on it.
• Fingernails grow faster than toenails
• Humans shed about 600,000 particles of
skin every hour.
• That’s about 1.5 pounds a year.
• By the age of 70 years of age, an average
person will have lost 105 pounds of skin.
SEVEN FUNCTION OF THE SKIN
• Protection
• Body temperature
regulation
• Waterproof
• Excretion and
absorption
• Helps to manufacture
vitamin D
• Cutaneous
sensations
– Site of many nerve
endings
• Temporary storage of
fat glucose, water,
and salts such as
sodium and chloride
• Screens out harmful
ultraviolet radiation
(UV) contained in
sunlight.
• It can absorb certain
drugs and other
chemicals
Layers of skin
• DERMIS
– 2nd layer
– Has wider variety of
sensory receptors
– Contains dense
connective tissue
• EPIDERMIS
– Outer most
– Has sensory receptors
– Contains stratified
squamous epithelial
cells
Layers of epidermis
• 5 layers
• In order from deep to superficial
– Stratum basale
– S. spinosum
– S. granulosum
– S. lucidum
– S. corneum
S. Corneum
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Dead cells
Outermost layer
waterfproof
Cells rub off
Replaced every 35-45 days
LUCIDUM, GRANULOSUM,
SPINOSUM
• Cells become flattened
• become full of keratin
• die
S. Basale
• Composed of single rstem cells that
undergo cell division to continually
produce new kertinocytes.ow of cuboidal
or columnar keratinocytes.
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EPIDERMIS
• Avascular
• Contains melanocytes
– Cells that make melanin
• Keratinocytes
– Most epidermal cells
– Produce keratin which is a protein that helps to give
epidermis its protective layer
• As these cells are pushed upward, keratin will
become the dominant structure in the cells.
Melanin
• Responsible for the color of skin, eyes,
hair
• Melanocyte
– Cell with projections that weave between
other cells
– Produce melanin
• Melanocytes are in greatest concentration
in nipples, anal region, and armpits
• Protects from UV radiation
• Pigment ranges from yellow to black
• Pigment protects from UV
• Freckles/moles
– Melanin concentration in one spot
• Over exposure to UV can cause cancer.
Langerhans cells
• Langerhans – easily damaged by UV
• works with immune system against
microbes that invade the skin
Merkel cells
• Merkel cells contact the flattened process
of a sensory neuron called a tactile
(Merkel
PARTS OF THE SKIN
Label the diagram and give the
function of the following parts
PARTS OF THE SKIN
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Epidermis
Dermis
Hair shaft
Papillae
Arrector pili muscle
Sebaceous gland
Sweat gland
Pore
Subcutaneous layer
• Nerve
• Blood vessels
• Adipose
DERMIS
• Composed of areolar connective tissue
containing collage and elastic fibers
• Dermal papillae section with small
fingerlike projections that indent the
epidermis.
– Meissner corpuscles
– Free nerve endings
Reticular layer
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Deeper layer of dermis
Contains blood vessels
Sweat / oil glands
Deep pressure receptors
Hair follicles
Collage and elastic fibers in the region
provides the skin with strength and
extensibility and elasticity
Accessory structures of skin
HAIR
• Protects the body
• Not present on palms, palmar surfaces of
fingers, soles and plantar surfaces of toes
• Head region – guards the scalp from injury
and the sun’s rays
• Eyebrows / eyelashes – protect the eyes
• Nostrils – protects against inhaling insects
and foreign particles
Hair structures
• Cuticle – single layer of cells (shingles)
– Cntains keratin
– As it wear away hair gets fizzy and gets split
ends
• Cortex – inner layer
• Medulla – central core
• Shaft – central portion and is above the
suface
• Root – portion below the surface and
penetrates into the dermis and
subcutaneous layer
• Hair follicle – surrounds root
– Contains growth region
• Arrector pili - when contracted it causes
hair to stand up – goose bumps
Glands
• Sebaceous galnds
• Sudoriferous glands
– Eccrine
– Appocrine
• Ceruminous glands
Sebaceous glands
• Oil glands
• Found all over the skin, except palms and
soles
• Ducts empty into the hair follicle
• Some open directly onto the dkin
• Sebum
Sebum
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Product of sebaceous glands
Oily
Contains chemicals that kill bacteria
Lubricant
– Keeps skin soft, moist
– Keeps hair from becoming brittle
• More active during adolescence
Sudoriferous glands
• Sweat glands
• Widely distributed in skin
• Two tyes
– Eccrine
– apocrine
Eccrine glands
• Most common
• Start to function soon after birth
• Found all over body, except margins of
lips, nail beds of fingers, toes, glans penis,
glans clitoris, labia minor, and eardrums
• produce sweat – contains water, salts,
urea, uric acid, vit. C
• pH 4 to 6
• Regulates body heat
Apocrine Sweat Glands
• Found in the skin of the armpit, groin, areolae of
the breasts, bearded regions of the face in
males.
• Duct empties into hair follicle
• Secretion - fatty acids and proteins along with
normal substances found in sweat
• Bacteria live on skin and when they break down
these secretion, body odor results
• Stimulated during emotional stress, sexual
excitement
• Do not begin to function until puberty
Ceruminous glands
• Se-ROO-mu-nus glands
• Present in external auditory canal
• \combination of secretions of ther
ceruminous and sebaceous glands
• Called earwax
• Forms a sticky barrier against foreigh
bodies.
Additional sensory receptors
• Free nerve endings
– Simplest
– No structural specializations
– Receptors for pain, thermal, tickle, itch, and
some touch sensations
• Encapsulated
– Dendrites are enclosed in a connective tissue
capsule
Touch
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Meissner corpuscles
Hair root plexuses
Merkel disks
Ruffini corpuscles
Pressure / vibration
• Pacinian (pa-SIN – e – an )
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Skin color
• 3 pigments
– Melanin
– Carotene – yellow orange pigment.
– Hemoglobin – oxygen carrying pigment in
RBS
• Freckles
• Age spots
Disease / disorders
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Skin graft
Psoriasis
Jaundice
Cyanotic
Hirsutism
transdermal drug administration
Albinism
Decubitus ulcers
wart
Burns
• Burns are traumatic injury as the result of
radiation from the sun, heat lam or contact
with boiling water, steam, fire, chemicals,
or electricity.
• When the sin is burned, dehydration, and
infection may occur.
• Either condition is life-threatening
Degree of burns
• First
• Second
• Third
Skin cancer
• Associated with exposure to UV light
Common types of skin cancer
• Basal cell carcinoma
• Squamous cell carcinoma
• Malignant melanoma
What to look for
• Brown or black irregular parch which
occurs early
• Color or size change in preexisting wart or
more
The skin and its relationship to
microorganisms
• An intact skin is the best way the body can
protect itself against pathogens and water
loss.
• Cracking of dry skin can be prevented by
lotions and creams
• The skin’s surface is not a favorable place
for bacteria to grow because it is too dry.
• Skin bacteria grows where there is
nutrients and moisture present.
• Most bacteria are found where the hair
follicles and sweat glands are located.
• Underarm perspiration odor is caused by
the interaction of bacteria on perspiration.
• This can be prevented by washing and
using deoderants.
HANDWASHING
• #1 way to prevent the spread of disease.
• 10 – 30 seconds normal
• 2 – 4 minutes if you are in contact with
infectious material.
• Exposure to blood or body secretions –
wash hands, apply gloves, remove gloves
and rewash hands.
AGING
• Most visible sings of aging are visible on
the skin.
• Secrete less oil therefore skin becomes
dry and more fragile.
• Skin loses elastin fibers causing the skin
to lose elasticity.
• Loss of subcutaneous fat causes wrinkles,
lines, and sagging.
• The dermal vascular network decreases in
its ability to respond to heat and cold.