Transcript ANATOMY

ANATOMY
INTEGUMENTARY
SYSTEM
Chapter 4
Classifications of
Membranes
 Epithelial
 Cutaneous
 Mucosa
 Serous
 Connective
 Synovial
Cutaneous Membranes
 Cutaneous- a dry membrane
 Outermost protective boundary (skin)
 Superficial epidermis
 Keratinized stratified
squamous epithelium
 Underlying dermis
 Mostly dense
connective tissue
Mucosa
 Surface epithelium
 Type depends on site
 Underlying loose connective
tissue (lamina propria)
 Lines all body cavities
that open to the
exterior body surface
 Often adapted
for absorption
or secretion
Serous
 Surface simple
squamous epithelium
 Underlying areolar
connective tissue
 Lines open body
cavities that are closed
to the exterior of the
body
 Serous layers
separated by serous
fluid
Specific Serous
Membranes
 Peritoneum
 Abdominal
cavity
 Pleura
 Around the
lungs
 Pericardium
 Around the
heart
Connective- Synovial
 Synovial
membrane
 Connective tissue
only
 Lines fibrous
capsules
surrounding joints
Skin’s Functions
 Protects deeper tissues from:
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Mechanical damage
Chemical damage
Bacterial damage
Thermal damage
Ultraviolet radiation
Desiccation
 Aids in heat regulation
 Aids in excretion of urea and uric acid
 Synthesizes vitamin D
Skin Structure
 Epidermis – outer layer
 Stratified squamous
epithelium
 Often keratinized
(hardened by keratin)
 Dermis
 Dense connective tissue
Hypodermis
(Subcutaneous Tissue)
 Below the dermis
 Not part of the skin
 Anchors skin to
underlying organs
 Composed mostly of
adipose tissue
Layers of the Epidermis
1. Stratum basale
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Cells undergoing mitosis
Lies next to dermis
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
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Occurs only in thick skin
5. Stratum corneum
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Shingle-like dead cells
Dermis
 Two layers
 Papillary layer
 Projections called dermal papillae
(fingerprints!)
 Pain receptors
 Capillary loops
 Reticular layer
 Blood vessels
 Glands
 Nerve receptors
Melanin
 Pigment produced by melanocytes
 Amount produced depends on genetics
and sun exposure
 Yellow, brown, black
color
 Found in stratum
basale
Normal Skin Determinants
 Melanin
 Yellow, brown or black pigments
 Carotene
 Orange-yellow pigment from some vegetables
 Hemoglobin
 Red coloring from blood cells in dermis
capillaries
 Oxygen content determines the extent of red
coloring
SWEAT GLANDS
 aka sudoriferous glands
 Found over entire skin
surface except nipples and
part of external genitalia
 > 2.5 million per person
Eccrine sweat glands
 More numerous, Located
EVERYWHERE!
 Abundant on palms, soles of feet
and forehead
 secretory part of gland coiled in
dermis
 Duct extends to open in a “pore”
Apocrine sweat glands
 Located in armpit and genital areas
 Begin to function at puberty under
influence of androgens
 Thought to play role in sexual
attraction (scent glands in animals)
 Secrete fatty acids and proteins
causing a yellowish color
 Odorless, but bacteria feast on
secretions giving musky odor
Sweat and Its Function
 Composition
 Mostly water plus salts (NaCl)
 Some metabolic waste (urea, ammonia, uric acid)
 Acidic pH 4-6, inhibits bacteria
 Fatty acids and proteins (apocrine only)
 Function
 Helps dissipate excess heat
 Excretes waste products
 Acidic nature inhibits bacteria growth
SEBACEOUS
GLANDS
WHAT ARE THEY?
 aka oil glands
 secrete an oily substance called
sebum
 sebum is produced within
specialized cells and is released
as these cells burst;
 sebaceous glands are thus
classified as holocrine glands.
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 Sebum is a mixture of fat and debris
of dead fat-producing cells. These
cells are constantly replaced by new
growth at the base of the glands.
 sebum is deposited on the hairs
inside the follicles and brought up to
the surface of the skin along the
hair shaft.
 In hairless areas, the sebum
surfaces through ducts or pores
 Sebum acts to protect and
waterproof hair and skin, and
keep them from becoming dry,
brittle, and cracked.
 It can also inhibit the growth of
microorganisms on skin since it
contains antimicrobial substances
 Found everywhere on the
body except the palms
of the hands and soles of
the feet.
At the rim of the eyelids are a
specialized form of sebaceous
gland that secrete sebum into
the tears coating the eye to
prevent evaporation.
 The sebaceous glands of a
human fetus in utero secrete
a substance called vernix
caseosa, a "waxy" or "cheesy"
white substance coating the
skin of newborns
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 The activity of the
sebaceous glands increases
during puberty because of
heightened levels of
androgens (sex hormones).
 Overactive
sebaceous
glands can
cause skin
problems such
as acne.
 The extreme use of anabolic
steroids by bodybuilders
for muscle gain tend to
stimulate the sebaceous
glands which can cause acne.
 A blocked sebaceous gland can
result in a sebaceous cyst.
 Dry skin is caused by underactive oil
glands
 as we get older, as our bodies don't
produce these natural oils so
effectively.
 Babies and young children are also
often susceptible to dry skin because
the sebaceous glands haven't
developed properly.
Appendages of the Skin
 Hair
 Produced by hair
bulb
 Consists of hard
keratinized
epithelial cells
 Melanocytes
provide pigment
for hair color
Figure 4.7c
Hair Anatomy
 Central medulla
 Cortex surrounds
medulla
 Cuticle on outside of
cortex
 Most heavily
keratinized
Figure 4.7b
Associated Hair
Structures
 Hair follicle
 Dermal and epidermal
sheath surround hair
root
 Arrector pilli
 Smooth muscle
 Lifts hair upright,
“goosebumps”
 Sebaceous gland
 Sweat gland
Figure 4.7a
Appendages of the Skin
 Nails
 Scale-like modifications of the
epidermis
 Heavily keratinized
 Stratum basale extends beneath the
nail bed
 Responsible for growth
 Lack of pigment makes them colorless
Nail Structures
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Free edge
Body
Root of nail
Eponychium
– proximal
nail fold that
projects onto
the nail body
Figure 4.9
Skin Homeostatic
Imbalances
 Infections
 Athletes foot
 Caused by fungal infection
 Boils and carbuncles
 Caused by bacterial infection
 Cold sores
 Caused by virus
Skin Homeostatic
Imbalances
 Infections and allergies
 Contact dermatitis
 Exposures cause allergic reaction
 Impetigo
 Caused by bacterial infection
 Psoriasis
 Cause is unknown
 Triggered by trauma, infection, stress
BURNS
AND
SKIN CANCERS
BURNS
BURNS
What are they?
What causes them?
 A burn is damage to your
body's tissues caused by
heat, chemicals, electricity,
sunlight or radiation.
 Scalds from hot liquids and
steam, building fires and
flammable liquids and
gases are the most
common causes of burns.
 There are three types of
burns depending on how
severe the burn is and its
damage to underlying tissues:
 First degree
 Second degree
 Third degree
Rule of Nines
 Way to determine
the extent of
burns
 Body is divided
into 11 areas for
quick estimation
 Each area
represents about
9%
First-degree burns
 damage only the outer layer
of skin-the epidermis
 Only symptom is redness of
skin
 are painful
Example: sunburn
Second-degree burns
 damage the epidermis and
the dermis
 Causes blisters to form as
epidermis separates from
the dermis
 Also painful
Second
degree
burns
Third-degree burns
 damage or destroy both layers
of skin and tissues underneath
 patients often require skin
grafts
 usually painless because the
nerve endings that supply pain
sensation are destroyed
Third degree burns
 Burns can cause swelling, blistering,
scarring and, in serious cases, shock
and even death.
 Swelling and blistering come from
fluids seeping out of the blood vessels
 This fluid loss creates one of the
greatest dangers from burns-fluid
loss and dehydration.
 Fluid loss can be so great as
to lead to depletion of blood
volume and shock and
dangerously low blood pressure
 Death is likely if the fluids
are not replenished (IV fluid
replacement with isotonic
saline or plasma)
 Another great danger of
burns is infection because
they damage your skin’s
protective barrier.
Antibiotic creams can
prevent or treat
infections..
 1st and 2nd degree burns
can heal over time without
skin grafts since there is
enough underlying skin to
repair the skin.
 After a third-degree burn,
skin or synthetic grafts
may be needed to cover
exposed tissue and
encourage new skin to grow.
This is as good as it
will ever get. These
scars are for life!
SKIN
CANCERS
Basal Cell Carcinoma
 Least malignant but MOST COMMON
 Sun exposed areas
 Invade the dermis and hypodermis
Squamous Cell carcinoma
 Scaly, reddend papule
 Sun-induced, metastasizes to lymph nodes
Malignant Melanoma
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Cancer of Melanocytes
Only 5% of cancers, but increasing
MOST DEADLY (survival 50%)
Some develop from moles
ABCD’s
 A= Asymmetry
 2 sides do not match
 B= Border Irregularity
 Not smooth, indentations
 C= Color
 Different colors: reds, tans, blacks, brown
 D= Diameter
 larger than 6mm
 E= Evolution