Transcript THE INTEGUMENTARY SYSTEM

PROTECTION – from injury, chemicals,
temperature, and bacteria
 PREVENTS water loss by producing
KERATIN – a water proofing protein
 REGULATES body temperature
 EXCRETES excess water and salt
 PRODUCES vitamin D
 SENSES our environment

EPIDERMIS – outer layer
composed of stratified
squamous epithelium
DERMIS – located directly
below the epidermis –
composed mostly of
dense connective tissue
SUBCUTANEOUS or
HYPODERMIS – located
below the dermis –
composed mostly of
adipose tissue

COMPOSED OF FIVE
LAYERS (STRATA)
› Stratum corneum
› Stratum lucidum
› Stratum granulosum
› Stratum spinosum
› Stratum basale

STRATUM BASALE
› Receives the most
adequate nourishment
because it is closest to
the dermis
› Constantly undergo
mitosis
› Daughter cells are
pushed upward closer
to the skin’s surface
and away from
nutrition
› Also called stratum
germinativum
• STRATUM SPINOSUM and
STRATUM GRANULOSUM
• Cells become
increasingly flat and full
of keratin.
• STRATUM LUCIDUM
• layer in which cells die
– only found where
skin is hairless and
extra thick – palms of
hand and soles of feet

STRATUM CORNEUM
› 20 to 30 cell layers
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thick
Cells are completely
dead and fully
keratinized
Creates hard layer
that protects cells
underneath
Average person loses
40 lbs. of this layer in
their lifetime!
Replaced by cells of
stratum basale every
25 – 45 days.
Specialized cells found
primarily in the stratum
basale
 Produce the pigment
known as MELANIN –
ranges in color from
yellow to brown to
black
 Production is
stimulated by sunlight
 Freckles and moles are
seen where melanin is
concentrated in one
area.

Melanin production
is genetically
determined.
PAPILLARY LAYER
› Upper dermal region
› Has projections called
PAPILLAE which
indent the epidermis
above
› Papillae of hands and
feet are arranged in
definite patterns –
these form fingerprints
› Layer that houses
touch ( Meissner’s
corpuscles) and pain
receptors (free nerve
endings)
Papillary layer

RETICULAR LAYER
› Deepest skin layer
› Contains blood
vessels, sweat, and oil
glands
› Has deep pressure
receptors called
Pacinian corpuscles
› Contains collagen
which gives skin its
strength
› Contains elastic fibers
which give skin
elasticity or
“stretchiness”
Reticular layer

Amount of MELANIN – ranges from
yellow to brown to black
 Amount of CAROTENE – a yellow-orange
pigment found in foods like carrots – the
body deposits it in stratum corneum and
subcutaneous layer
 Amount of HEMOGLOBIN – blood
pigment that shows through from the
dermal capillaries


SEBACEOUS GLANDS
› Produce oils
(sebum) that keep
skin moist and soft
› Prevent hair from
becoming brittle
› Sebum contains
chemicals that kill
bacteria
Sebaceous
gland

SWEAT(SUDORIFEROUS)
GLANDS
› ECCRINE sweat glands
secrete primarily water
and empty from pores
distributed on the
body’s surface
› APOCRINE sweat glands
are primarily in the
axillary and genital
regions and secrete into
hair follicles – associated
with body odors
Sweat
glands

HAIR
› Produced by an
EPIDERMAL structure
called the hair FOLLICLE
› Composed of three
layers: medulla, cortex
and cuticle
› The cuticle is formed by
highly keratinized, dead
epithelial cells.
› The arrector pili muscle
attached to the hair
follicle are the cause of
“goose bumps”
Hair Structure
Medulla
(core)
Cortex
Cuticle

NAILS
› Modification of the
epidermis having a
free edge, body
(visible attached
portion) and root
(embedded in skin)
› Heavily keratinized
and colorless –
appear pink because
of blood supply
below.
› Grows from the nail
bed or matrix

BURN – damage or cell death caused by
heat, electricity, radiation, or chemicals
› 1st Degree – only the epidermis is damaged
› 2nd Degree – damage the epidermis and
upper region of the dermis – blisters are likely
› 3rd Degree – entire thickness of the skin is
destroyed – regeneration isn’t possible – skin
grafts must be done to replace damaged
tissue
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ATHLETE’S FOOT – itchy, red, peeling condition
between toes – caused by a fungus
COLD SORES – fluid filled blisters that itch and
sting – caused by herpes simplex virus –
activated by upset, fever, or UV light
PSORIASIS – chronic condition producing too
many skin cells – believed to be an
autoimmune condition in which the immune
system attacks a person’s own tissues.
ACNE – condition caused by over-production
in the sebaceous glands – prevalent in teens
because of hormonal changes

SKIN CANCERS
› Basal Cell Carcinoma – least
malignant and most
common – appear as lesions
in areas that have been
exposed to a lot of sun –
relatively slow growing
› Squamous Cell Carcinoma –
appears as a scaly, red
lesion – eventually forms an
ulcer on the surface of the
skin – appear most often on
scalp, ears, and lips – also
believed to be sun-induced.

SKIN CANCERS
› Melignant Melanoma
– begins wherever there
is pigment – appear
spontaneously or where
there is existing pigment
› DIAGNOSIS
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Asymmetry
Border irregularity
Color
Diameter
Elevation