Membranes found all throughout body Functions of body membranes:
Line or cover body surfaces – separate in/out
Protect body surfaces Lubricate body surfaces
Classified into two types: Epithelial membranes
o Cutaneous membraneo Mucous membraneo Serous membrane
Connective tissue membraneso Synovial membrane
o Cutaneous membrane = skin Function: protect deeper body tissues dry membrane Outermost protective boundary consisting of:
Superficial epidermis Contains keratin in areas of high friction
Underlying dermis Mostly dense connective tissue - protection
Figure 4.1a
o Mucous membranes 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)
o 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
Specific serous membranes Peritoneum
• Abdominal cavity Pleura
• Around the lungs Inside = visceral Outside = parietal
Pericardium• Around the heart
Inside = visceral Outside = parietal
o Synovial membrane Function: lubrication for
friction Connective tissue only Lines fibrous capsules
surrounding joints
Figure 4.2
Four major functions 1. Protects deeper tissues from:
o Mechanical damageo Chemical damageo Bacterial damageo Thermal damageo Ultraviolet radiationo Desiccation (drying out)
2. Aids in heat regulationo Maintain 98.6°F body temperature
3. Aids in excretion of urea and uric acido Both nitrogen-based toxins
4. Synthesizes vitamin Do Needed to help body absorb calcium for bones
Comprised of two things: Skin (cutaneous membrane) Skin appendages/derivatives (objects coming
from skin)o Sweat glands o Oil glands (sebaceous glands)o Hairso Nails
o Epidermis – outer layer Stratified squamous
epithelium (many flat layers)
Often keratinized (hardened by keratin)
o Dermis Dense connective tissue
Figure 4.3
o 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
Stratum corneum Shingle-like dead cells; 25-
30 layers Stratum lucidum
Occurs only in thickened skin (calluses, corns)
Stratum granulosum Stratum spinosum Stratum basale
Cells undergoing mitosis Lies next to dermis
Pigment melanin produced by melanocytes is present in epidermis 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
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 Reticular layer
Blood vessels Glands Sensory receptors (Pacinian corpuscle [pressure]
and Meissner’s corpuscle [light touch])
Figure 4.4
Three things actually determine skin color: Melanin
o Yellow, brown or black pigments Carotene
o Orange-yellow pigment found in some vegetables that deposits itself in our skin
Eating too many carrots WILL turn skin orange
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.
Hemoglobino Red coloring from blood cells in dermis capillarieso Oxygen content determines the extent of red
coloring Light red = oxygenated (arteries) Dark red = deoxygenated (veins)
Emotional stimuli and/or disease may cause alterations in skin color: Erythema: redness due to blood vessel dilation
o Blushing, hypertension, inflammation, allergy Pallor: blanching (loss of color) of skin
o Emotional stress, low blood pressure, low hemoglobin
Jaundice: yellowingo Excess bile due to liver disorder
Hematomas: bruises
Many appendages/derivatives of skin. Four major ones:
1. Sebaceous glands 2. Sweat (sudoriferous) glands 3. hair 4. nails
1. Sebaceous glands Produce oil called sebum
o Lubricant for skino Kills bacteria
Most with ducts that empty into hair follicles Glands are activated at puberty
2. Sweat glands Widely distributed in
skin Two types
o Eccrine (merocrine) Open via duct to
pore on skin surface
o Apocrine Ducts empty into
hair follicles
Composition of sweat:o Mostly watero 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 productso Acidic nature inhibits bacteria
growth Odor is from associated bacteria
3. Hair 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
Anatomy:o Central medulla
Innermost segment only present with thick hairs
o Cortex Middle segment – 90% of hair shaft strength, color, texture
o Cuticleo Outermost section o thin, colorless, protection for cortex
o Most heavily keratinized structure of body
Figure 4.7b
Structures associated with hair:o Hair follicle
Dermal and epidermal sheath surround hair root
o Arrector pilli Tiny smooth muscle causes
hair to stand upo Sebaceous glando Sweat gland
o Apocrine only
Figure 4.7a
4. Nails Scale-like modifications
of the epidermiso Heavily keratinized
Stratum basale extends beneath the nail bed in matrixo Responsible for
growth Lack of pigment makes
them colorlessLee Redmond
Guinness World Record Holder – until February 2009 when a car
accident broke her nails
Nail structure:o Free edge – what we cuto Body – main nail lying on bedo Root of nailo Eponychium – proximal nail fold that
projects onto the nail body (cuticle)o Matrix – stratum basale
Figure 4.9
Infections or allergies Athletes foot
o Caused by fungal infection Boils and carbuncles
o Caused by bacterial infection of hair follicle
Cold soreso Caused by viral infection
Herpes simplex I
Contact dermatitiso 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
Psoriasiso Cause is unknowno Triggered by trauma, infection, stress
Onycholysis o Separation of nail from
nail bedo Symptom of trauma or
infection Cyanosis
o Bluish (cyan) coloringo Symptom of inadequate
oxygen in the bloodo Common in newborns
Pressure ulcers (bedsore)o Lack of unrelieved pressure,
friction, humidity, temperature, age, continence and medication
o Disrupts blood flow & oxygen to cells, killing them
Burnso Tissue damage and cell death caused by heat,
electricity, UV radiation, or chemicalso Associated dangers
Infection Dehydration Electrolyte imbalance Circulatory shock
o Way to immediately determine the extent of burns is with the “Rule of Nines” 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
Burns are categorized by severity in degreeso 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
o Third-degree burns Destroys entire skin layer Burn is gray-white or black
Epidermis
Dermis
1°2°3°
Burns are considered critical if:o Over 25% of body has second degree burnso Over 10% of body has third degree burnso Third degree burns on face, hands, or feet
Skin cancer – abnormal cell mass (tumor) of epidermiso 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
o 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
Malignant melanoma Cancer of
melanocytes Most deadly of
skin cancers Metastasizes
rapidly to lymph and blood vessels
o 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
Chemotherapy affects integumentary system more than any other systemo 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
Many changes in integumentary system occur from conception to death Hair changes Skin changes
Hair changeso Fetus has downy hair called lanugoo Oilier hair during adolescenceo Loses luster (shininess) with ageo Male pattern baldness common
Hair still produced but degenerated follicles produce fine, colorless hair (that may not emerge from hair follicle)
o Graying hair Decrease in melanin
Skin changeso Newborn baby’s skin covered
with vernix caseosa White cheesy-like
substance produced by sebaceous glands to protect it from amniotic fluid
o Newborn also has milia or “baby acne,” accumulations in sebaceous glands which disappear in few days
o Newborn skin will thicken over time with added subcutaneous fat
o Elderly people lose subcutaneous fatty tissue resulting in “thin skin” Tendency to become colder
faster Blood vessels get damaged
easily (bruise easily)
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