Integumentary

System
 Name the parts of the Integumentary system and discuss the function of
each part.

 Define the combining forms used in building words that relate to the
Integumentary system.

 Identify the meaning of related abbreviations.

 Name the common diagnoses, laboratory tests, and clinical procedures

used in testing and treating the Integumentary system.
 • Consists of skin, hair, nails and
various glands
• Two major components:
• Cutaneous membrane (skin)
• Epithelial tissues
• Epidermis - superficial
• Dermis – underlying
connective tissue
• Accessory structures
• Hair, nails, exocrine glands
• Hypodermis (subcutaneous
layer) – loose connective tissue
under the dermis
• Separates the integument
from deeper tissues and
The Integumentary organs
• Often not considered part of
the integumentary system
System
Accessory structures
• originate in the dermis
• Some extend through
the epidermis to the
skin surface
• Hair
• Nails
• Multicellular exocrine
glands
 General Functions of
the Integument
1. Protection
• Skin covers underlying tissues and
prevents fluid loss

2. Temperature maintenance
• Skin regulates heat exchange with the
environment

3. Synthesis and storage of nutrients

• Epidermis synthesizes vitamin D 3
• Dermis stores lipids in adipose tissue
 General Functions of
the Integument
4. Sensory reception
• Receptors for pain, pressure, touch, and
temperature detect stimuli and send
information to the nervous system

5. Excretion and secretion

• Glands excrete salts, water, and organic
wastes
• Specialized mammary glands secrete milk
6. Production of melanin and keratin
SEATWORK #1
1 – 2 Two components of the integumentary system
3 – 4 2 layers of the skin
5 – the scientific term for SKIN
6 – the scientific term for hypodermis
7 – what does avascular mean?
8 – 10 3 glands in the integumentary system
10 – 15 five functions of the integumentary system
Structure
and
Function
Layers of
the skin
 Epidermis

 Outermost skin layer

 Consists of several sublayers
 Top sublayer is called the
stratum corneum
 Nonvascular
 Keratin is found in the cells
 Stratum germinativum is the
bottom sublayer where new cells
are produced that push up
toward the stratum corneum
 Epidermis
Stratified Squamous Epithelium
• Thick skin has five layers (palms,
soles)
• Thin skin has four layers (rest of
body)
• Layers are called strata, from deep
to superficial
Stratum basale
Three intermediate layers
• Stratum spinosum, stratum granulosum, and
stratum lucidum
Stratum corneum
 • Also called stratum germinativum
• Attached to the basement
membrane by
Stratum Basale •
hemidesmosomes
Forms epidermal ridges down into
the dermis
• Dermis has dermal papillae up into
epidermis
• Epidermis is avascular
• Ridges and papillae increase
the surface area for diffusion
between the dermis and
epidermis
• Contains basal or germinative
cells
 Stratum
Basale
• Contours of skin follow ridge
patterns
• Ridge contours are
genetically determined =>
unique to each person and
don’t change
• Fingerprints – ridge patterns
of the fingers
 • Stratum spinosum is the
result of stem cell division
Intermediate • Stratum granulosum cells
Strata •
make a lot of keratin
A protein that provides water
resistance and the
foundation for hair and nails
• In others, horns, hooves,
feathers, baleen
• Stratum lucidum cells are
densely packed into a
highly keratinized layer –
only thick skin
 Stratum Corneum
• At the exposed surface of the skin
• Contains 15–30 layers of keratinized
or cornified dead cells
• Cells are connected via
desmosomes and are therefore shed
in large groups (sheets rather than
individuals)
• Takes 7-10 days to move from
stratum basale to stratum corneum
• After two weeks in stratum
corneum, shed or washed away
 Skin Color
Role of pigmentation
• Carotene is orange-yellow,
accumulates in the epidermis,
and comes from orange-
colored foods
• Can be converted to vitamin A
• required for normal maintenance of
epithelial tissues
• Synthesis of photoreceptors in the eye
Skin Color Role of pigmentation
• Melanin is brown, yellow-
brown, or black, produced
by melanocytes near
stratum basale cells,
absorbs ultraviolet (UV)
radiation protecting deeper
layers
• Freckles are areas of
greater melanin
production
• Small amount of UV –
good for stimulating
vitamin D
• Larger amounts cause
burns
• Variations in skin color are
due to differences in
melanin production not
number of cells
Melanocytes
• Melanocytes are highly
differentiated cells that
produce the pigment melanin
within melanosomes.
• This cell has a dark
appearance and a dendritic
shape.
• Melanin production is the
primary function of
melanocytes.
 Melanin and
sunburn
Melanin helps to block harmful
UV rays to some extent, which is
why people with naturally darker
skin are less likely to get
sunburned, whereas people with
lighter skin are more likely to
burn. Sunburns can increase
your chances of developing skin
cancer, including melanoma.
 Melanin
• Melanin is a substance in your body
that causes pigmentation in your hair,
eyes, and skin.
• The more melanin you produce, your
eyes, hair, and skin will be darker.
• The amount of melanin in your body is
determined by several factors,
including genetics and the amount of
sun exposure your ancestors received.
 Skin color
distribution
Prior to the last 500 years of mass
global migrations of people, dark skin
color was mostly concentrated in the
southern hemisphere near the equator,
while light skin color gradually
increased farther away, as shown in
the map below. In fact, the majority of
people with dark skin lived within 20
degrees north of the equator. The
majority of the lighter-pigmented
people lived north of 20° N latitude,
where ultraviolet radiation is much
less intense on average.
 Albinism
• Light-colored skin or hair
• Melanin is not produced in melanocytes
even though in normal abundance
• The reduced amount of melanin can
cause eye problems. This is because
melanin is involved in the development of
the retina, the thin layer of cells at the
back of the eye.
• Because people with albinism lack
melanin in their skin, they're at increased
risk of getting sunburn and skin cancer.
Skin Color
Role of dermal circulation
• Oxygenated blood is bright red resulting
in a flushed, red skin color when dermal
blood vessels dilate
• Short-term paling of the skin occurs
with vasoconstriction
• Cyanosis, a bluish coloration, occurs
when blood oxygen supplies are
diminished
Beneficial Effects of Sunlight on Skin
Vitamin D 3 is derived from:
• A cholesterol-related steroid in the
epidermis when exposed to sunlight

Vitamin D 3 is modified by:

• The liver and the kidneys into calcitriol,
essential for calcium and phosphorus
absorption in the small intestine
• Lack of vitamins can lead to weak and
flexible bones
 Detrimental
Effects of Sunlight
on Skin
Skin cancers
• Basal cell carcinoma is the
most common
Originating in stratum basale
• Squamous cell carcinoma
found in more superficial
layers
• Both are treatable in most
cases
• Surgical removal of tumor is
most common treatment
 Skin cancers
• Malignant melanoma is
the most dangerous
Usually begins from a
mole, and can metastasize
through the lymphatic
system
Survival depends on when
detected and when
treatment begins.
• Avoiding UV radiation by
Detrimental Effects using sunblock can help
prevent all three types
of Sunlight on Skin
Dermis
• Also called the corium
• Contains two sublayers the
papillary layer and the
reticular layer
• Holds many capillaries, lymph
cells, nerve endings,
sebaceous and sweat glands
and hair follicles
• Collagen fibers are found in
the connective tissue and
when collagen fibers stretch,
they form striae
The Dermal Papillary Layer
• Named for the dermal
papillae
• Just deep to, and projects up
into, the epidermis
• Contains capillaries and
nerves supplying the
epidermis
The Dermal Reticular Layer
• Interwoven meshwork of dense,
irregular connective tissue
• As well as mixed in cells of
connective tissue proper
• Elastic and collagen fibers are
present
• Combine to establish the right
balance of flexibility and
stability
• Collagen fibers extend from up
into the dermal papillae
• Down into the hypodermis
The Dermal Reticular Layer
Hair follicles and sweat glands derived from the
epidermis
• Extend down into the dermis

Cutaneous plexus —blood vessels from the

hypodermis—extends up into the reticular layer
• Provides oxygen/nutrients and removes carbon
dioxide/waste

Blood vessels, lymphatics, and nerves

• Supply nutrients, eliminate wastes, control secretions,
and respond to stimuli
The Dermis
Innervation of the Skin

Nerve fibers in skin control:

• Blood flow

• Glands secretions

• Sensory receptors provide information to the

nervous system.
• Light touch – tactile corpuscles (Meissner’s corpuscles),
located in the dermal papillae
• Deep pressure and vibration – lamellated corpuscles
(Pacinian corpuscles), in the reticular layer.
The Hypodermis
Also called the subcutaneous layer
• Deep to the dermis without a clear line
separating them

Not actually part of the integument

• But stabilizes the skin to underlying
tissues

Made of areolar tissue with many

adipose cells
• Baby fat – cushions and reduces heat loss
The Hypodermis
Fat layers change as we age
• Men – neck, upper arms, lower
back
• Women – buttocks, breasts,
hips, thighs
• Both - abdomen

No vital organs in the area

make it an ideal site for
subcutaneous injections
Thin VS Thick skin
• Except for the hands, arms, and
feet, the entire body has thin
skin. It has a thinner top layer
and no stratum lucidum layer.
• Thick skin is hairless and lacks
sebaceous glands and apocrine
sweat glands, whereas thin skin
has hair follicles as well as
eccrine and apocrine sweat
glands.
Hair and Hair Follicles
• Are accessory organs of the
integumentary system
• Hairs are nonliving structures
produced in hair follicles
• Project above the skin
surface everywhere except:
• The soles of the feet, palms of
the hands, sides of the fingers
and toes, the lips, and portions
of the external genitalia
 • Protects the scalp – UV
light, helps cushion from
the light blow, insulates
Functions of Hair • Prevents entry of foreign
particles into the nose,
eyes, and ears
• Prevents injury via
sensory perception – i.e.
swat mosquito
• Expresses emotional
state by hair standing up,
due to contraction of
arrector pili muscle
Hair and Hair
Follicles

• Hair matrix grows, making hair

longer, and cells become
keratinized and die
• Halfway to the skin surface, it
becomes the hair root
• Above the surface it is called
the hair shaft
• Shaft has three layers of dead
cells
• From outer to inner: cuticle,
cortex, and medulla
 Accessory structures of hair
Arrector pili
• Involuntary smooth muscle
connected to the hair root.
• Causes hair to stand up
• Produces goosebumps
Sebaceous glands
• Secrete sebum (oil)
• Lubricate the hair
• Control bacteria
Regions of the Hair
Hair root
• The lower part of the hair
beneath the surface
• Anchors hair
Hair shaft
• Part of the hair that extends
past the surface (exposed)
• Not attached to the
integuments
Hair Production
Begins at the base of a hair,
deep in the dermis
• The hair papilla contains
capillaries
• The hair bulb produces hair
matrix
• A layer of dividing basal cells
• Produces hair structure
• Pushes hair up and out of the
skin
Hair Color
Differences due to type and amount
of melanin from melanocytes
• Genetically determined

Aging results in less pigment

production
• Causing gray or white hair
• Due to lack of pigment and bubbles in
air shaft
Types of hair
Vellus hair

• Soft, fine

• Cover body surface

Terminal hair

• Thick, maybe heavily pigmented

• Eyebrows, head, and eyelashes

• Other parts of the body upon puberty

 •Secrete oily sebum into the
hair follicle
• secreted when arrector
pili muscles contract –
squeezes sebaceous
glands and forces
secretions into hair
follicles
• Lubricates and inhibits the
growth of bacteria
•Sebaceous follicles secrete
sebum directly onto:
Sebaceous Glands of • Skin of face, back, chest,
nipples, and external
genitalia
the Skin
Sebaceous Glands of the Skin
• Sebaceous glands are microscopic glands found
in hair follicles that secrete sebum.

• Sebum is an oily substance that keeps your skin

from drying out.

• Sebaceous glands can clog, so keep your glands

healthy by following a skincare routine that
includes cleansing and moisturizing your skin.

• Sebaceous glands are sensitive to hormonal

changes – accelerate at puberty

• Inflamed glands can result in acne

Different types of sebaceous glands
Simple branched alveolar glands
• Associated with hair follicles
Sebaceous follicles
• Discharge directly onto the skin
surface
Sebum
• Contains lipids and other
ingredients
• Lubricates and protects the
epidermis
• Inhibits bacteria
Sweat Glands
• Also called
sudoriferous glands
• Include two types
• Apocrine sweat glands
• Merocrine sweat glands
Apocrine Sweat Glands
• Become active at puberty
• Secrete sticky, cloudy
sweat into hair follicles
in armpits, around
nipples, and in the pubic
region
• Sweat is food source for
bacteria on skin,
increasing odor
Merocrine Sweat Glands
• Also called eccrine sweat glands
• Very numerous with high numbers on
soles and palms
• Coiled tubular structure secretes watery
perspiration directly onto the surface of
the skin
• Sweat also contains electrolytes, urea,
and organic nutrients
• Sodium chloride gives it the salty taste
• function is to cool the body through
evaporation and also provides protection
from hazards
• Dilutes harmful chemicals
• Contains dermcidin – antibiotic properties
Modified Sweat Glands
Mammary glands
• Secrete milk

Ceruminous glands
• Secrete a waxy substance that
combines with sebaceous oils to
form earwax
Nails

Protect tips of fingers and toes

Visible nail body
• Made of dense, keratinized cells
recessed under surrounding
epithelium
Nail bed
• Deeper level of epithelium
covered by nail body
Structure
Nail root
• The nail root is the portion of the nail
found under the surface of the skin at
the near (or proximal) end of the nail. It
is where the nail begins. The nail plate
(or body) is the portion of the nail that is
external to the skin.(

Lunula
• Pale crescent near root
Structure
Nail matrix
• The nail matrix is the area where your
fingernails and toenails start to grow.
The matrix creates new skin cells,
which pushes out the old, dead skin

cells to make your nails .

Structure
Cuticle
• The cuticle is a layer of clear skin
that runs along the bottom edge of
your finger or toe. This is referred to
as the nail bed. The cuticle's function
is to protect new nails from bacteria
as they grow from the nail root.
Structure
Nail Plate
to protect the living nail bed underneath.

Nail bed
area of the nail on which the nail plate
rests. Nerves and blood vessels found here
supply nourishment to the entire nail unit.

Nail fold
protect the nail matrix.