The Integumentary System
Anatomy and Physiology
Integumentary System
Skin
and all its appendages
(hair, nails, skin glands) are
considered organs of the
Integumentary system.
Integument is another name for
skin.
What are the major
characteristics of the skin?

Waterproof, stretchable,washable, and
automatically repairs small cuts, rips and
burns and is guaranteed to last a lifetime.
 Surface area of up to 2.2 square meters
 11 pounds
 7% of total body weight
 Pliable yet tough
What are the major layers of the skin?

Cutaneous membrane
– Epidermis (epi-upon)
 Composed of epithelial tissue (keratinized stratified
squamous)
 Non-vascularized
– Dermis – underlies the epidermis
 Tough leathery layer composed of fibrous connective
tissue
 Good supply of blood
 Subcutaneous layer (Hypodermis/superficial fascia)
– Made of adipose and areolar tissue
– Stores fat, anchors skin, protects against blows
keratin
Epidermis
Dermis
Basement membrane
Epidermis
Dermis
Hypodermis
What are the different types of cells in the epidermis?

Keratinocytes
– Produce a fibrous protein
called keratin
– Pushed upward by the
production of new cells
beneath them.
– Become dead and scale-like
– Millions rub off everyday
What are the different types of
cells in the epidermis?
 Melanocytes
– Synthesizes the
pigment melanin
– Melan-black
– Can transfer melanin
to keratinocytes
– Protects skin from
ultraviolet light.
melanocyte
Melanin in
keratinocytes
What are the different types of
cells in the epidermis?

Langerhans’ cells
– Serve a defense role
(along with helper T
cells) by triggering
immune reactions in the
case of pathogenic
conditions
– Formed in bone marrow.
– Move to the skin
Langerhans’
cell
What are the different types of
cells in the epidermis?

Merkel Cells
– Has a spiked
appearance
– Connected to nerve
cells from dermis
– Function as sensory
receptors for touch.
What are the layers of the
epidermis?

Stratum corneum
 Stratum lucidum
 Stratum granulosum
 Stratum spinosum
 Stratum basale
Stratum corneum

Outermost layer 20-30
flat dead keratinized
cells.
– Dandruff
– Average person shed 40
pounds of these cells in
their lifetime.
– Everything you see on a
human is dead!
Stratum lucidum

thin, clear, translucent
layer.
 Cells flat and closely
packed.
 Absent in thin skin.
Stratum granulosum

Keratinization is here.
 Stained granules
called keratohylin
(required for keratin
formation) present.
 This region is absent
in some thin skin.
Stratum spinosum

Intermediate layer
 Contain spiny shaped
keratinocytes.
 Cuboidal shape.
Stratum basale

Deepest layer of the
epidermis
 Undergoes rapid cell
division (mitosis).
 Columnar shaped
Epidermal Growth & Repair

To function in protection, the epidermis must rely on
its ability to create & repair itself following an
injury.
 New cells must be made at the same rate that dead
cells flake off.
 Cells push off from the stratum basale into each
upper layer until they die.
 Regeneration time for a cell is about 35 days.
Epidermal-Dermal Junction

Composed of adhesive basement membrane
 Cements epidermis to dermis
 Barrier has limited role in preventing the
passage of harmful chemicals or pathogens
 Detachment of the junction can result in
serious infection and death
What are the characteristics of
the dermis?

Made up of connective tissue
 Richly supplied with blood vessels and
lymph vessels
 Has hair follicles, oil and sweat glands and
sensory receptors
 Has papillary & Reticular layer.
– Ridges formed from the papillary layer can
form finger prints.
Papillary Layer

The thin superficial layer of dermis forms
wavy bumps called dermal papillae.
– These project into dermis to make finger prints.

Composed of loose connective tissue
Reticular layer of the dermis

Filled with dense irregular fibrous connective tissue
 Matrix is filled with thick bundles of collagen fibers
(give the skin strength)
 Serves as a point of attachment for muscle fibers
 Hair follicles have a bundle of involuntary muscles
called arrector pilli muscles.
– Make hair stand on end.

Specialized sensory receptors located in dermis
Dermal growth and repair


Does not continually regenerate like epidermis.
Regeneration usually happens only in the cause of
healing wounds.
 In the healing of a wound, fibroblasts in dermis
reproduce and form dense mass of connective
tissue fibers.
 Fibers orient themselves in patterns called
Langer’s cleavage lines.
 If elastic fibers stretch too much the result is
stretch marks.
Langer’s
cleavage Lines

Surgeons make
incisions parallel to
these lines.
 This ensures that
wounds will not
gape open.
Best incision
Incision
will gape
What are the 3 types of burns?

First-degree burns: only the epidermis is
damaged. Redness, swelling and pain are
common. (sunburn) 2-3 days to heal
 Second-degree burns: epidermis and
upper layers of dermis. Blistering can
occur. 3-4 weeks to heal.
 Third-degree burns: involves the entire
thickness of the skin.
First degree burn
Second-degree burn
Third-degree burn
Rule of 9s

Method used to estimate the amount of body area
burned.
Rule of Palms

Based on the assumption that a palm is about 1% of
the victims body.
 Also used to estimate about of body burned.
Skin Burns Brochure

Create a Brochure
describing and illustrating
the 3 types of burns
– 1st degree
– 2nd degree
– 3rd degree

Describe the characteristics
of each type of burn and the
skin layer/s affected.
 Create the brochure as if
you were informing the
public how to identify each
type of burn.

You must have 2 drawings
for each burn:
– one drawing will show the
layers of the skin at a
microscopic level;
– one drawing will show a full
body with the burns as we see
it on a macroscopic level.
What causes the color of
skin?

3 pigments contribute to skin color
– Melanin- protein pigment (natural sunscreen)
 Scattered through out the stratum basale of the epidermis.
 If melanocytes cannot form melanin then albinism results.
 Prolong exposure to sun increases melanin production
– Carotene-yellow to orange pigment found in carrots.
 Most commonly found in the palms or soles. Most intense
when large amounts of carotene-rich foods are eaten.
– Hemoglobin- Red blood gives a pinkish hue to fair skin
 Unoxygenated blood results in cyanosis or blue skin
What are the major
appendages of the skin?

Hairs
 Nails
 Sweat glands
 Sebaceous glands
Why is hair useful?

Senses insects that land on the skin.
 Hair on the head protects the head from a
blow, sunlight and heat loss.
 Eyelashes shield the eye
 Nose hairs filter the air
What are hairs?

The shaft is the visible portion of hair.
 Shaft has 3 layers of cells
– Medulla(central core)
– Cortex (bulky layer)
– Cuticle (heavily keratinized; protects hair)

Sebaceous glands secrete an oily sebum to keep hair
lubricated.
Why do
humans
have
arrector pili
muscles?
What are the parts of nails?

A nail is a scalelike modification of the
epidermis
 Made of tightly compressed keratinized cells
 The nail body is the visible portion of the nail
 Root is the part of the nail that lies under the
fold of skin called the cuticle.
 Nail matrix is the region responsible for nail
growth.
What are the types of glands found
in the skin?

Sweat glands-(sudoriferous): most numerous in skin.
– Eccrine- most common sweat glands



Found everywhere except lips, ear canal, nail beds, & penis.
Helps maintain body temperature.
Secretory portion starts in subcutaneous tissue layer.
– Apocrine
– Found deep in subcutaneous layer of skin of the arm pits and
genitalia



Thought to be scent glands.
Ceruminous- produce cerumen (ear wax)
Sebaceous glands- oil glands (sebum)
– Softens and lubricates hair and skin
– Slows water loss and kills bacteria
– Over secretion can cause acne
What are the primary functions of the
Integumentary System?

Protection: provides 3 types of barriers
– Chemical barriers: low pH of skin secretions
slows bacterial growth.
– Physical barriers: very few substance are able
to enter the skin. Substances able to pass.
– Biological barriers: Langerhans’ cells- act as
macrophages police the epidermis for viruses
and bacteria.
Functions cont.

Thermoregulation- skin contains sweat glands
that secrete watery fluid, that when evaporated,
cools the body.
 Sensation- Skin contains sensory receptors that
detect cold, touch, and pain.
 Vitamin D synthesis- cholesterol in the skin is
bombarded by sunlight and converted to vitamin
D (calcium cannot be absorbed from digestive
tract)
Functions cont.

Blood reservoir- blood will be moved from
skin to muscles during strenuous activity.
 Excretion- Sweating is an important outlet
for wastes such as salt and nitrogen
containing compounds. (urine)
Skin Cancer

Benign tumors such as warts and moles are
not serious.
 Malignant tumors can start on the skin and
invade other body areas.
 Crucial risk factor- overexposure to UV
radiation
Types of Skin Cancer

Basal cell carcinoma- most common, 30% of all
white skin people get it.
– Arises from the stratum basale layer of the skin
– 99% curable if caught early
– Dome shaped nodules that form an ulcer in the center.

Squamous Cell carcinoma– Arise from stratum spinosum
– Grows rapidly and metastasizes if not removed
– Small red rounded elevation on the skin
Skin Cancer Types cont.

Melanoma
– Cancer of melanocytes (very dangerous)
– 5% of skin cancers but rising fast
– Can arise from preexisting moles
– Appears as a spreading brown or black patch
– Chance of survival is poor if the lesion is
greater than 4 mm thick
Basal Cell Carcinoma
Lesion removed from patient
Basal Cell Carcinoma
Squamous cell carcinoma
Melanoma
What is the ABCD rule?

Used for recognizing melanoma
 A-Asymmetry: two sides of the pigmented
mole do not match
 B-Border irregularity: borders are not
smooth
 C- Color: lesion has a multiple of colors
 D- Diameter the spot is larger than 6 mm in
diameter (size of a pencil eraser)
Skin Cancer Awareness Flyer

Design a flyer meant to inform the public how to
identify cancerous moles.
 Inform them about the different types of skin
cancer.
 Tell the public about the ABCD rule with
illustrations.
 These will be hung up in the hallways: you just
might inform one of your fellow classmates and
save a life!