Transcript Cutaneous membrane

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Membranes found all throughout body
Functions of body membranes:
 Line or cover body surfaces – separate
in/out
 Protect body surfaces
 Lubricate body surfaces
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Classified into two types:
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Epithelial membranes
Cutaneous membrane
o Mucous membrane
o Serous membrane
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Connective tissue membranes
o
Synovial membrane
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Cutaneous membrane = skin
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Function: protect deeper body tissues
dry membrane
Outermost protective boundary consisting of:
 Superficial epidermis
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Contains keratin in areas of high friction
Underlying dermis
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Mostly dense connective tissue - protection
Figure 4.1a
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Mucous membranes
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Function: protect from drying out, lubrication
Lines all body cavities that open to the exterior body
surface
Often adapted for absorption (i.e. large intestine) or
secretion (i.e. nasal cavity)
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Serous membranes
Function: lubrication for cushion, friction
 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
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Specific serous membranes
 Peritoneum
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Abdominal cavity
Pleura
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Around the lungs
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Inside = visceral
Outside = parietal
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Pericardium
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Around the heart
Inside = visceral
 Outside = parietal
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Synovial membrane
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Function: lubrication for
friction
Connective tissue only
Lines fibrous capsules
surrounding joints
Figure 4.2
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Four major functions
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1. Protects deeper tissues from:
o Mechanical damage
o Chemical damage
o Bacterial damage
o Thermal damage
o Ultraviolet radiation
o Desiccation (drying out)
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2. Aids in heat regulation
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3. Aids in excretion of urea and uric acid
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Maintain 98.6°F body temperature
Both nitrogen-based toxins
4. Synthesizes vitamin D
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Needed to help body absorb calcium for bones
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Comprised of two things:
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Skin (cutaneous membrane)
Skin appendages/derivatives (objects coming
from skin)
o Sweat glands (sudoriferous glands)
o Oil glands (sebaceous glands)
o Hairs
o Nails
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Epidermis – outer layer
 Stratified squamous
epithelium (many flat
layers)
 Often keratinized
(hardened by keratin)
Dermis
 Dense connective tissue
Figure 4.3
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Under dermis is the
hypodermis
Not part of the skin
 Anchors skin to
underlying organs
 Composed mostly of
adipose (connective)
tissue
 Where blood vessels
are located
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Stratum corneum
 Shingle-like dead cells; 2530 layers
Stratum lucidum
 Occurs only in thickened
skin (calluses, corns)
Stratum granulosum
Stratum spinosum
Stratum basale
 Cells undergoing mitosis
 Lies next to dermis
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Pigment melanin produced by melanocytes is
present in epidermis
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Color varies from yellows to browns to blacks
Melanocytes are mostly in the stratum basale
Amount of melanin produced depends upon
genetics and exposure to sunlight
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Papillary layer
 Finger-like projections just under epidermis called
dermal papillae (form fingerprints)
 Pain receptors (nociceptors) at ends of nerves
 Capillary beds/loops (blood vessels) where veins &
arteries meet
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Reticular layer
 Blood vessels
 Glands
 Sensory receptors (Pacinian corpuscle [pressure]
and Meissner’s corpuscle [light touch])
Figure 4.4
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Three things actually determine skin color:
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Melanin
o Yellow, brown or black pigments
Carotene
o Orange-yellow pigment found in some
vegetables that deposits itself in our skin
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Eating too many carrots WILL turn skin orange
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During the filming of the
show, teenager Susan
developed anorexia.
She only ate carrots for
weeks at a time.
Eventually, directors had to
stop filming because her
skin was orange.
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Hemoglobin
o Red coloring from blood cells in dermis capillaries
o Oxygen content determines the extent of red
coloring
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Light red = oxygenated (arteries)
Dark red = deoxygenated (veins)
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Emotional stimuli and/or disease may cause
alterations in skin color:
 Erythema: redness due to blood vessel dilation
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Blushing, hypertension, inflammation, allergy
Pallor: blanching (loss of color) of skin
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Emotional stress, low blood pressure, low
hemoglobin
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Jaundice: yellowing
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Excess bile due to liver disorder
Hematomas: bruises
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Many appendages/derivatives of skin. Four
major ones:
1. Sebaceous glands
2. Sweat (sudoriferous) glands
3. hair
4. nails
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1. Sebaceous glands
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Produce oil called sebum
o Lubricant for skin
o Kills bacteria
Most with ducts that empty into hair follicles
Glands are activated at puberty
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2. Sweat glands
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Widely distributed in
skin
Two types
o Eccrine (merocrine)
 Open via duct to
pore on skin
surface
o Apocrine
 Ducts empty into
hair follicles
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Composition of sweat:
o Mostly water
o Some metabolic waste (i.e. garlic)
o Fatty acids and proteins (apocrine
only)
Function of sweat:
o Helps dissipate excess heat as
evaporation occurs
o Excretes waste products
o Acidic nature inhibits bacteria
growth
Odor is from associated bacteria
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3. Hair
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Produced by hair
bulb
Nourished at papilla
due to blood vessels
Consists of hard
keratinized
epithelial cells
Melanocytes
provide pigment for
hair color
Figure 4.7c
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Anatomy:
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Central medulla
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Cortex
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Middle segment – 90% of hair shaft
strength, color, texture
Cuticle
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Innermost segment
only present with thick hairs
Outermost section
thin, colorless, protection for cortex
Most heavily keratinized
structure of body
Figure 4.7b
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Structures associated with
hair:
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Hair follicle
 Dermal and epidermal sheath
surround hair root
Arrector pilli
 Tiny smooth muscle causes
hair to stand up
Sebaceous gland
Sweat gland
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Apocrine only
Figure 4.7a
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4. Nails
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Scale-like modifications
of the epidermis
o Heavily keratinized
Stratum basale extends
beneath the nail bed in
matrix
o Responsible for
growth
Lack of pigment makes
them colorless
Lee Redmond
Guinness World Record Holder –
until February 2009 when a car
accident broke her nails
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Nail structure:
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Free edge – what we cut
Body – main nail lying on bed
Root of nail
Eponychium – proximal nail fold that
projects onto the nail body (cuticle)
Matrix – stratum basale
Figure 4.9
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Infections or allergies
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Athletes foot
o Caused by fungal infection
Boils and carbuncles
o Caused by bacterial infection of
hair follicle
Cold sores
o Caused by viral infection
 Herpes simplex I
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Contact dermatitis
o Exposures cause allergic reaction
Eczema (atopic dermatitis)
o Hypersensitivity reaction (allergy)
o Most common in infants & many
outgrow it
Impetigo
o Caused by bacterial infection usually
a result of eczema
Psoriasis
o Cause is unknown
o Triggered by trauma, infection, stress
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Onycholysis
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Separation of nail from nail
bed
Symptom of trauma or
infection
Cyanosis
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Bluish (cyan) coloring
Symptom of inadequate
oxygen in the blood
Common in newborns
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Pressure ulcers (bedsore)
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Lack of unrelieved pressure,
friction, humidity, temperature,
age, continence and medication
Disrupts blood flow & oxygen to
cells, killing them
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Burns
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Tissue damage and cell death caused by heat,
electricity, UV radiation, or chemicals
Associated dangers
 Infection
 Dehydration
 Electrolyte imbalance
 Circulatory shock
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Way to immediately
determine the extent
of burns is with the
“Rule of Nines”
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Body is divided into 11
areas for quick
estimation
 Each area represents
about 9%
 One side of leg = 9%
 One whole arm = 9%
Figure 4.11a
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Burns are categorized by severity in degrees
o First-degree burns
 Only epidermis is damaged
 Skin is red and swollen
o Second-degree burns
 Epidermis and upper dermis are damaged
 Skin is red with blisters
1°
o Third-degree burns
Epidermis
 Destroys entire skin layer
 Burn is gray-white or black
2°
3°
Dermis
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Burns are considered critical if:
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Over 25% of body has second degree burns
Over 10% of body has third degree burns
Third degree burns on face, hands, or feet
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Skin cancer – abnormal
cell mass (tumor) of
epidermis
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Two types of tumors
 Benign
 Does not spread
(encapsulated)
 Slow-growing
 Malignant
 Can metastasize
(moves) to other
parts of the body
 Fast-growing (starve
other cells)
Epidermis
Dermis
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Three types of skin cancer:
 Basal cell carcinoma
 Least malignant
 Most common type
 Arises from stratum basale
 Squamous cell carcinoma
 Arises from stratum
spinosum
 Metastasizes to lymph nodes
 Early removal allows a good
chance of cure
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Malignant melanoma
 Cancer of
melanocytes
 Most deadly of
skin cancers
 Metastasizes
rapidly to lymph
and blood vessels
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Detection of skin cancer uses ABCDE rule
 A = Asymmetry
 Two sides of pigmented mole do not match
 B = Border irregularity
 Borders of mole are not smooth
 C = Color
 Different colors in pigmented area
 D = Diameter
 Spot is larger than 6 mm in diameter
 E = Evolving
 Changing over time in size, color, texture
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Chemotherapy affects integumentary system more than
any other system
o Drugs target rapidly dividing cells (cancer)
o Integument has rapidly dividing cells (stratum basale)
in matrix area
 Loss of hair – destroys matrix
 Dry skin – destroys stratum basale
 Dry brittle nails – destroys matrix
 Dry mouth & throat – destroys mucus membranes
 Nausea – destroys mucus membranes in stomach
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Many changes in integumentary
system occur from conception to
death
 Hair changes
 Skin changes
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Hair changes
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Fetus has downy hair called lanugo
Oilier hair during adolescence
Loses luster (shininess) with age
Male pattern baldness common
 Hair still produced but degenerated follicles
produce fine, colorless hair (that may not emerge
from hair follicle)
Graying hair
 Decrease in melanin
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Skin changes
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Newborn baby’s skin covered
with vernix caseosa
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White cheesy-like substance
produced by sebaceous
glands to protect it from
amniotic fluid
Newborn also has milia or “baby
acne,” accumulations in
sebaceous glands which
disappear in few days
Newborn skin will thicken over
time with added subcutaneous
fat
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Elderly people lose
subcutaneous fatty tissue
resulting in “thin skin”
 Tendency to become colder
faster
 Blood vessels get damaged
easily (bruise easily)