Transcript THE SKIN

CH 5 Integumentary System
SKIN
• The integumentary system
includes the skin and its
accessory organs
• Another term for the skin is
the “cutaneous
membrane”.
Facts about the SKIN…
• Skin is waterproof
• The outer surface of the skin is made of dead cells.
House dust is mainly skin flakes!
• If you laid out all your skin on a flat surface, it
would have an area of about 2 square meters (22
square feet). Skin weighs about 2.5 kilograms (1215% of body weight) - the largest organ in the
body.
• What hurts if you pull it, but doesn't hurt if you cut
it?
– Your hair, of course!
• Skin is elastic - it springs back into shape when
stretched.
Skin Facts Continued….
• Some medicines (eg: oestrogen, nicotine)
can pass through the skin, but others
cannot (eg: insulin). Why is that? Because
only fat-soluble substances can enter the
skin, not water-soluble ones.
• Your hair stands on end and you develop
goose bumps because there are tiny
muscles attached to the hair follicles and
they contract when you are frightened or
cold.
The Skin and its Tissues
• Skin functions:
• Protective covering (primary function) – barrier
to the entry of microbes, viruses, and UV
exposure
• Aids in regulating body temperature
• Slows water loss
• Houses sensory receptors
• Synthesizes various chemicals (vitamin D and
melanin)
• Excretes waste
• The skin is composed of an epidermis, dermis,
and subcutaneous layer (hypodermis).
THE SKIN
Epidermis
Dermis
Subcutaneous
(Hypodermis)
The EPIDERMIS
• 4-5 layers of 4 different types of cells.
• The deepest layer of the epidermis contains cells
undergoing cell division (mitosis) to produce new cells.
• About 90% of the epidermis are keratinocytes.
• Epidermal cells become keratinocytes when they undergo
keratinization. During this process, they mature and are
pushed toward the surface while producing keratin (takes
about 2-4 weeks). What does keratin do?
– Gives tissue a waterproof quality
• Melanocytes produce the skin pigment melanin. Melanin is
a brown/black pigment that covers the nucleus to protect
the DNA from UV radiation- which can cause mutation. The
more that cells are exposed to UV radiation, the more
melanin is produced. A sun tan is a sign of injury!!
Epidermis Continued….
• Langerhans cells- Arise from red bone marrow
and move to the epidermis where they
participate in immune responses.
• Merkel cells- Found in the deepest layer of the
epidermis where they contact the flattened part
of a sensory nerve cell and function in the
sensation of touch.
Layers of the Epidermis- from the bottom to top
1. Stratum Basale- Here is where cell division takes
place, producing new skin cells and pushing older cells
toward the surface. This layer contains prekeratinocytes, melanocytes, Langerhans cells and
Merkel cells. This layer is attached to a layer of fibers
called the basement membrane.
2. Stratum Spinosum- Contains spiny keratinocytes that
are not yet mature enough to produce keratin.
3. Stratum Granulosum- Contains keratinocytes that
produce keratin.
4. Stratum Lucidum- Clear, flat, dead cells found only in
the thick skin of palms and soles.
5. Stratum Corneum- Thickest layer- 30 layers of flat,
dead keratinocytes.
LAYERS OF EPIDERMIS
Quick Review
1. Another name for skin is the
______________ membrane.
2. What are 5 functions of skin?
3. What are the 3 layers of skin?
4. What are the 4 types of cells found in the
epidermis?
5. What are the 5 layers of the epidermis?
6. Which layer contains functioning
keratinocytes?
7. Which layer is attached to the basement
membrane?
8. Which layer is the thickest?
Skin Cancer Facts
• Most skin tumors are benign (non-cancerous)–
ex. Warts, calluses, moles
• Skin cancers metastasize, which means that
they invade other tissues. If they enter the
bloodstream and/or lymph system, they can
travel anywhere and lodge themselves in other
locations.
• The cause of skin cancer is not known, but
overexposure to ultraviolet (UV) radiation is the
main risk factor. The DNA in a cell can become
mutated, and consequently, it divides out of
control.
Basal Cell Carcinoma
• Least malignant and most common skin cancer
• Most often appears on the exposed areas of the
face
• Appears as a shiny dome-shaped nodule that
later develops a central ulcer with a “pearly”
beaded edge
• Full cure in 99% that are removed surgically
• Cells of the stratum basale no longer form
keratin and do not honor the boundary between
dermis and epidermis
Basal Cell Carcinoma
Squamous Cell Carcinoma
• Arises from the cells of the stratum spinosum
• Occurs most often on the scalp, ears, hands,
and lower lip
• Appears as a scaly, reddened elevation that
gradually forms a shallow ulcer with a firm,
raised border
• It grows rapidly and metastasizes to adjacent
lymph nodes if not removed
• Chance for complete cure is good if caught early
and removed surgically or by radiation therapy
Squamous Cell
Carcinoma
Malignant Melanoma
• Cancer of the melanocytes
• 5% of all skin cancers
• Is often deadly and chance of survival is
50%...early detection helps.
• Can begin anywhere there is pigmentation, some
develop from pigmented moles.
• Usually appears as a spreading brown to black
patch that metastasizes rapidly to surrounding
lymph nodes and blood vessels.
• Use the ABCDE Rule to recognize it
Malignant Melanoma
The ABCDE rule is a convenient guide to
the usual signs of melanoma.
• A is for ASYMMETRY: Onehalf of a mole or birthmark
does not match the other.
• B is for BORDER: The edges
are irregular, ragged, notched,
or blurred.
• C is for COLOR The color is
not the same all over, but may
have differing shades of brown
or black, sometimes with
patches of red, white, or blue.
• D is for DIAMETER: The area
is larger than 6 millimeters
(about ¼ inch -- the size of a
pencil eraser)
• E is for EVOLVING: If the
growth changes at all
IMPORTANT NOTE: One blistering
sunburn in childhood or adolescence
more than doubles a person's
chances of developing melanoma
later in life. A person's risk for
melanoma also doubles if he or she
has had five or more sunburns at
any age.
The DERMIS
• Composed of 2 layers: papillary layer and reticular layer.
• Papillary layer contains a thin arrangement of collagen
fibers and supplies nutrients to select layers of the
epidermis and regulates temperature (by increasing and
reducing blood supply to the epidermis). The fingerlike
projections of this layer are called dermal papillae.
These cause ridges in the epidermis and are what
produce fingerprints.
• Inside the dermal papillae are blood vessels and nerve
endings. The nerve endings are called corpuscles of
touch or Meissner corpuscles. These are sensitive to
touch. What type of epidermal cell is closely associated
with these?
– Merkel Cells!
Dermis continued…..
• Reticular layer- The reticular layer is
contains thicker collagen fibers than the
papillary dermis. It strengthens the skin,
provides structure and provides elasticity.
It also supports other components of the
skin, such as hair follicles, nerves, oil
glands, muscles, and sweat glands.
HAIR
•
•
•
•
Also called pili- Each strand is dead, keratinized cells that
consist of a shaft (above the skin) and a root (below the
skin).
Surrounding the root is a hair follicle which includes an
external root sheath, internal root sheath, and connective
tissue sheath
The base of the follicle is the matrix- where new hair cells
are formed from cell division
Surrounding the follicle base is/are:
•
blood vessels- provide nourishment to the hair
• arrector pili muscle-contracts and causes the hair
to stand up (goose bumps)
• hair root plexus (nerve endings)
HAIR
Sebaceous Glands
• Sebaceous glands
usually are associated
with hair follicles
• Secrete sebum, which
keeps hair from drying
out
• If plugged and
infected…a pimple
develops
Sweat (Sudoriferous) Glands
– Each sweat gland consists of a coiled tube
(duct)
– 2 Types (Apocrine and Eccrine)
– Apocrine glands respond to emotional stress
– larger and occur in armpits (axillary
regions) and groin areas…these produce a
solution that bacteria act on to produce
“body odor”
– Eccrine glands respond to elevated body
temperature
– Sweat is primarily water, but also contains
salts and wastes
The SUBCUTANEOUS Layer
(Hypodermis)
• Adipose (fat) tissue helps
conserve body heat
• Contains blood vessels
that branch into the
dermis
• The layer where you
receive shots and
vaccinations…
Nails
• Nails are produced
by epidermal cells
originating at the
nail matrix that
undergo
keratinization
HOW SWEET ARE
THOSE NAILS??
Burns
•
•
Serious threat to skin
2 Life Threatening Problems associated with
Burns:
1. Body Fluid Loss-. Dehydration and electrolyte
imbalance follow and can lead to shutdown of
kidneys and circulatory shock
2. Infection- The leading cause of death in burn
victims. Burned skin is sterile for about 24 hrs. The
bacteria and fungi easily invade areas where the
skin is destroyed and feed off of the dead tissues.
The patient’s immune system becomes
overwhelmed and suppressed after severe burn
injury.
Rule of Nines
• The severity of a burn can be estimated by
determining how much of a body’s surface
is burned using the RULE OF NINES.
• This divides the body into regions and
states the surface area % of the body for
each region. See next slide.
Severity of Burns
• First Degree: Only the epidermis is
damaged. Not usually serious and can heal
in 2-3 days.
– Ex. Mild sunburn
First Degree Burns
• First-degree burns
involve minimal tissue
damage and they
involve upper layers
of the epidermis (skin
surface). These burns
cause pain, redness
and swelling.
First – Degree Burns
Second-Degree Burns
• Epidermis and upper
region of dermis is
damaged.
• Usually no permanent
scars.
Third-Degree Burns
• Third-degree burns affect the
epidermis, dermis and
hypodermis, causing charring
of skin or a translucent white
color, with coagulated vessels
visible just below the skin
surface. These burn areas may
be numb because nerves are
destroyed. Regeneration is not
possible and skin grafting must
be performed.
SEVERITY OF BURNS
1. Minor burns treated at home= First or seconddegree burns covering less than 15% of an
adult's body or less than 10% of a child's body,
or a third-degree burn on less than 2% BSA..
2. Moderate burns treated at a hospital= These
are defined as First or second-degree burns
covering 15%-25% of an adult's body or 10%20% of a child's body, or a third-degree burn on
2%-10% BSA.
• Critical, or major, burns should be treated
in a specialized burn unit of a hospital.
These are defined as First or seconddegree burns covering more than 25% of
an adult's body or more than 20% of a
child's body, or a third-degree burn on
more than 10% BSA. In addition, burns
involving the hands, feet, face, eyes, ears,
or genitals are considered critical.
For the following scenarios, indicate the
body surface area % that is burned and rate
the burn as minor, moderate or critical.
1. A child is burnt at a family bonfire. His
anterior right arm and entire left leg are
affected.
2. An adult woman was burnt using a
chicken fryer. Her left foot and posterior
left leg were affected.
Regulation of Body Temperature
• Regulation of body temperature is vital because heat
affects the rates of metabolic reactions
• Normal body temperature of deeper body parts is
about 37° C (98.6° F)
– Heat Production and loss
• When body temperature rises above normal, dermal blood
vessels dilate and sweat glands secrete sweat
• In hot weather, 4 liters per hour can be lost…so drink your
fluids!!!
• If body temperature drops below normal, dermal blood
vessels constrict and sweat glands become inactive
• During excessive heat loss, skeletal muscles are stimulated
to contract involuntarily (shivering)
Some actions involved in Body Temperature
Regulation:
Body Temp. Rises
Above Normal
Nervous System
Signals dermal Blood
vessels to dilate and
sweat glands to
secrete
Body Heat is
lost to
surroundings
Body Temp
returns to normal
Normal Body Temperature
37 C or 98.6 F
Body Temp
rises towards
normal
Body heat is
generated by
muscle contractions
Nervous System
signals dermal blood
vessels to constrict
and sweat glands
remain inactive
Body Temp drops
below normal
If body temp continues to drop,
Nervous system signals muscles to
Contract involuntarily (shivering)
ACNE
Acne is a common skin condition in which the sebaceous glands become
clogged. This causes a pimple and inflamed infected abscesses, or collections
of pus. The symptoms of this condition may include blackheads, whiteheads,
pimples, pustules, and cysts. Acne is caused by a hormonal change in the
body. It is usually inherited.
Allergic Contact Dermatitis –
A bumpy patch of itchy, flaky, red skin. It occurs when someone has a
reaction after coming into contact with something that irritates his/her skin.
Symptoms are: redness, itchy skin, crackling skin, blisters, spreading patch,
and oozing. Causes are: repeated contact, soaps, fabric softeners, perfumes,
cosmetics, nickel, deodorants, plants such as poison ivy, oak, or sumac.
Alopecia
Alopecia is a medical name for baldness or hair loss. Symptoms:
hair loss. Causes: Male-Patterned Baldness, which is the most
common, inflammation of the scalp, medications, chemotherapy,
radiation treatment of the head, infections such as syphilis, trauma to
the hair or scalp, low iron, low thyroid hormone levels, lupus, and
cancer
Athlete’s
Foot
Athlete’s Foot is a fungal infection that affects the top layer of skin
on the foot. Symptoms: Itching, itchy red rash between toes or
underneath the arch of the foot, small blisters, which contain pus,
skin may look inflamed, dry, and scaly. Causes: fungus
Boil/
Carbuncle
Boil/Carbuncle is an abscess which is a collection of pus in soft
tissues of the skin caused by bacterial infections and usually
involves a hair follicle. Symptoms: tender red swollen skin , with
an overlying pus head or a very tender soft lump in which the pus
may not be visible.
Cold Sore
Cold Sores are blisters inside the mouth or on the lips. Causes: a virus called
Herpes Simplex Virus Type I. Symptoms: tiny blisters, swelling and redness,
fever, not feeling well, feeling tired, hard to eat, and sore throat. Spread from
person to person easily, able to spread to other parts of the body, may become
infected with bacteria
Warts
Warts are non-cancerous skin growths caused by a viral infection
in the top layer of the skin. Viruses that cause warts are called
human papillomavirus (HPV). Warts are usually skin-colored and
feel rough to the touch, but they can be dark, flat and smooth. The
appearance of a wart depends on where it is growing.
Eczema
Eczema is a non-contagious skin condition that causes patches of dry, scaly,
extremely itchy skin. Symptoms: dry patches of skin, red extremely itchy skin,
rash, blisters, itching, constant dry, scaly skin. Causes: related to history
hypersensitivity or reaction in the body, people who have asthma or hay fever
are more likely to get eczema. Stress, dry climate, high temperature, soaps,
chlorine, and other irritating substances. Foods such as peanut butter, milk,
or eggs.
Fungal Nail
Infection
A fungal nail infection is a condition in which a fungus or yeast
causes a nail to become misshapen, discolored, and thick.
Symptoms: unattractive nails, itching, peeling, skin dryness, and
small blisters. Causes: fungal infection, bacterial buildup
Impetigo
Impetigo is a contagious bacterial
infection on the surface of the
skin. Symptoms: honey colored
crusts, mild sores, pus filled
blisters, blisters containing clear
yellow or slightly cloudy fluid.
Causes: scratches, cuts, or prior
existing skin diseases such as
eczema put a person at risk.
Keloid
Keloids are patches of
excessive scar tissue that
may form following a skin
injury. Symptoms: thick,
smooth humped-up pink scar
tissue larger that the original
site of injury, occasional
itching or tenderness.
Causes: cosmetics, piercings
Pediculosis
Pediculosis (lice) are small gray bugs. Symptoms: itchy scalp,
inflammation, bacterial infection, swollen lymph nodes, nits.
Causes: sharing hats, combs or headphones, wearing dirty
clothing for weeks.
Psoriasis
Psoriasis is an inherited disease that causes an increase in skin cells on the
outer layer of the skin. Cause: unknown, but allergies are thought to play a
role. Symptoms: red bumps or patches under dead skin, reddened areas that
itch or are tender, itching, scaling and red patches in the scalp, crumbling or
abnormal fingernails or toenails, thickening, cracking, and blistering of the
palms or soles of the feet.
Rosacea
Rosacea is a chronic
inflammation that occurs on
the face. Symptoms:
redness of the face,
overproduction of sebum,
inflamed acne like bumps,
mild swelling of the skin on
the cheeks and nose,
thickening of the oil glands in
skin of the nose, swelling of
tiny blood vessels on the
face. Cause: unknown
Scabies
Scabies is a skin
infestation caused by a
scabies mite. Symptoms:
itchy bumps in
characteristic locations
such as between fingers, or
on the wrists, or on the
genitals. Other symptoms
include generalized itching
and tiny burrow lines
Varicella
(Chickenpox)
Varicella is a disease caused by the varicella-zoster virus (ZVZ).
Symptoms: blistery, itchy rash, usually on all body surfaces, fever,
difficulty waking, trouble walking, stiff neck, breathing difficulty,
vomiting, red tender skin, a child who looks or acts sick, scabs that
become soft and drain a yellow pus (Chickenpox). We have a
vaccine now that prevents this disease.
Shingles
Shingles is a painful rash of
blisters that develops due to
the virus that causes
chickenpox. Symptoms:
sensations, pain, numbness,
tingling, itching, groups of
blisters. Causes: reactivation
of the chickenpox virus,
weakness of the immune
system
What is the skin disorder?
1.
2.
3.
4.
5.
6.
7.
skin infestation caused by a mite
increase in skin cells on the outer layer of the skin
baldness or hair loss
small gray bugs
caused by HPV- Human Papilloma Virus
reactivation of the chicken pox virus
redness of the face, overproduction of sebum, inflamed
acne like bumps
8. caused by Herpes Simplex Virus Type 1
9. fungal infection that affects the top layer of skin
10. patches of excessive scar tissue