Integumentary
Anatomy and Physiology
©Irene Mueller, EdD, RHIA
Montana Hospital Association
June 6, 2012
http://etc.usf.edu/clipart
Objectives
• Review Integumentary System Anatomy and
Physiology for ICD-10-CM/PCS Coding
– Functions of Integumentary System
– Layers of Skin
– Cells of Integumentary System
– Skin Tissues
– Nerves
– Glands
– Hair & Nails
– Breast
Overview
• Integument = Skin L, a covering
• Largest Organ of Human Body
– Weighs about 8 pounds (3.6 kgs)
– Covers 22 sq feet
– Contains 11 miles of blood vessels
• Worldwide, dead skin accounts for about one
billion tons of atmospheric dust
• Excretes up to 3 gallons of sweat on hot day
Functions of Skin
• Protection (physical & immuno-regulation)
• Contains Touch and pressure receptors
• Thermoregulation
• Secretion of Antibacterials & Synthesis of
Vitamin D
• Excretion of metabolic wastes
Protection Against …
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Microorganisms
Chemicals
Heat
UV radiation
Dehydration
Mechanical stresses
Sense of Touch
• Touch is composed of various senses
– Somatic - sensations of temperature,
pressure, & pain
– Kinesthetic - give conception of body in space
(proprioception)
– Visceral - such as stomach aches or nausea
Touch Sense
• In humans, about 90% of somatosensory
cortex processes touch signals from hands &
face
• Touch senses in these areas is
correspondingly sensitive/high-resolution
• Palm can detect presence of fraction of gram
Touch receptors
• Hairless skin (Glabrous) has finest receptors
– Mechanoreceptors translate physical force into
nerve impulses
– Four main mechanoreceptors in hairless skin areas
• Pacinian corpuscles
• Meissner's corpuscles
• Merkel's discs
• Ruffini corpuscles
Touch processing
• Processed in postcentral gyrus
– About top middle area of brain
– Often referred to as primary somatosensory
cortex
– More direct sensory input information than
any other part of brain
Thermoregulation
• Skin is major organ controlling
heat & moisture flow to/from
surrounding environment
• Skin also has thermal sensors
– participate in thermoregulatory
control
– affect person’s thermal sensation &
comfort
Heat production
• Most of body’s heat production is in
– Liver
– Brain
– Heart
– Skeletal muscles during exercise
• Human body is only 25%
efficient
– loses approximately 75% of
energy as heat
Regulating Body Temperature
• Heat is transferred
– Through network of blood vessels & tissue
– To skin
• Heat exchange mechanisms include
– Heat transfer at skin surface via
• Conduction (sitting on cold surface)
• Convection (air temperature colder than body)
• Radiation (long-wave and short-wave)
– Via moisture evaporating/diffusing through skin
– Sweat evaporation on skin surface
– Respiration from lungs
Brain and Body Heat
• Brain is about 2% of body mass, BUT
produces about 15% of body’s total
metabolism
– During high mental activity, this neuron
metabolism can more than double
– Head has specialized thermoregulatory
physiology
• Assures high rates of heat loss
• Keeps brain temperature constant
Thermoregulation
• Core temperature regulated by brain’s
hypothalamus (AKA body’s thermostat)
• Hypothalamus responds to various
temperature receptors located thruout
body
• Makes physiological adjustments to
maintain constant core temperature
– EX: On a hot day, temperature receptors
located in skin send signals to hypothalamus
to increase sweat rate
Sweating
• Average person has 2.6 million sweat
glands
• Sweat is made up of water & electrolytes
such as sodium, chloride, and potassium
• When hypothalamus senses increase in
core temperature
– increases blood flow to skin
– stimulates sweat glands
• Result - increase in rate of water lost
through sweating
Secretion of Antimicrobials
• The skin generates a number of
antimicrobial peptides/proteins (AMPs)
• Provide a front-line component in innate
immunity
• Inhibit microbial invasion
Synthesis of Vitamin D
• UV rays from sun strike skin
• D from sun exposure, food, & supplements is
biologically inert
• Must undergo 2 hydroxylations in body
• Liver converts D to 25-hydroxyvitamin D
[25(OH)D], AKA calcidiol
• Kidney forms physiologically active 1,25dihydroxyvitamin D [1,25(OH)2D], AKA
calcitriol
Excretion of Wastes
• Integumentary system supports excretory
system in removal of waste
• Skin provides for removal of
– dead cells and sweat - contains waste products
• Hair, fingernails & toenails
– accumulations of dead epidermal cells
• As more cells die
– Need removal
– Hair & nails grow
Waste in Sweat
• Sweat contains metabolic waste
products—primarily
– Sodium chloride
– Urea
– Lactic acid
– Potassium ions
Components of
Integumentary System
• Integument = average of 1 mm thick
– Epidermis
– Dermis
– Hypodermis
• Accessory Tissues (Dermal Appendages)
– Sweat glands
– Oil (sebaceous) glands
– Hair
– Nails
Layers of Skin
• Epidermis
– Five layers
– Keratin-producing cells
• Dermis (Cuteus)
– True skin
• Hypodermis
– Subcutaneous layer of connective tissue
– Contains dermal appendages
– Nerves
– Blood vessels that supply dermis
http://www.nlm.nih.gov/medlineplus/ency/imagepages/8912.htm
Epidermis
• About 0.012 cm thick
• Can thicken for greater protection
– Constant friction/pressure
– Callus or Corn
• Average turnover time for epidermis = ?
Epidermis Strata
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Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basele
http://www.nku.edu/~dempseyd/skin%20layers.jpg
Stratum Corneum
• Outermost, Toughest layer of skin
• First defense against
– Microorganisms, UV, chemicals, heat
• Flat, dead skin cells
• Cells are cornified, filled with keratin
Stratum Lucidum
• Clear layer holding substance
– Becomes keratin as cells ascend
– Pre-keratin = Eleidin
• Eleidin is found mostly in palms/soles
– Thick skin
Stratum Granulosum
• Flattened cells – No nuclei
• Granular appearance
• Due to Keratohyalin
– Also becomes Keratin
Stratum Spinosum
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AKA Squamous
Larger layer
Produces keratin for epidermis
Spinous processes projecting between
adjacent, new Keratincytes
Stratum Basale
• AKA Germinativum
• Single layer
– Cuboidal and
columnar cells
– Undergo mitosis
– Keratinocytes
divide
• Begin to move up
Dermis
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AKA cuteus or corium
2 layers
Papillary - L, papilla, nipple
Reticular - L, reticulum, little net
– having a netlike pattern or structure
• Lymph vessels are in this layer
Papillary layer
• Top layer of Dermis
• Fingerlike projections interface with
Epidermis
• Give texture to surface (form rete pegs)
– Loss of rete pegs with aging
– Skin gets thinner
– Skin gets smooth, shiny, paper-thin
– Lose fingerprints
Reticular Layer
• Main layer of Dermis
• Rest of connective tissue in Dermis
Hypodermis
• AKA Subcutaneous
• Layer of cushioning fat at base
• Superficial fascia connecting dermis to
muscle
Epidermal Cells
• Four types of cells
– Keratinocytes
Gk, keras, horn
– Melanocytes
Gk, melanin, black
– Langerhans cells
– Merkel cells
• Each one can have specific types of tumors
Keratinocytes
• Produce Keratin
– Scleroprotein, main
component of
– Hair, skin, nails
– tough and insoluable
– Hard, unmineralized
structures on many
animals
• Scales, claws, horns,
hooves, feathers, shells
• Divide and grow in
lower epidermal layers,
then flatten, stack, and
cornify as they ascend
• Kerartinization
(Cornification)
– Outer epidermal layer is
waterproof and prevents
dehydration
Melanocytes
• Produce Melanin
– Pigment that colors skin and hair
– Melanocytes in darker-skinned people are more
active; same number of melanocytes
– Moles, freckles, suntans
– Protects the skin against UV radiation
• Located in lowest level of epidermis
– Stratum basale
Langerhans Cells
• Paul Langerhans (1847 - 1888) German
pathologist, physiologist & biologist
• Migrate from bone marrow
• Begin immune response against antigens
due to infection
– Similar to macrophages
• Located in stratum spinosum layer
Merkel Cells
• Friedrich S. Merkel, German anatomist
– Described in 1875
• Function not completely understood
– Light touch for hand dexterity
– Discrimination of shapes/structures
– Both sensory and hormonal functions
– Sometimes referred to as neuroendocrine cells
• Located in basal layer
Dermal Cells
• 3 types of cells
– Fibroblasts
– Mast cells
– Macrophages
• Each type has different function
Fibroblasts
• Synthesize extracellular matrix precursors
– Collagen
– Reticular and elastic fibers
– Glycoproteins
• Determines properties of connective tissue
• Structural framework of dermis; ability to
move
• Main function
– Maintain structural integrity of skin
Mast cells
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AKA mastocyte or labrocyte
In tissues with some interface to outside
Also found in digestive and respiratory tracts
Do NOT circulate
Hypersensitivity reactions of skin
Contain/release chemical mediators
(histamine, etc.) in response to triggers
Mast cells, cont.
• Triggers vary & are
individual
– External OR Internal
– Can vary from day to day
• Set off a mast cell response
– Antibiotics, foods, food
additives
– Stress, fatigue, heat, cold,
sunlight
– Bacteria or fungi
– Toxins, smells
• When triggered
• Degranulate
– Release chemicals
– All at once OR
– Slow, leaky process
Macrophages
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Gk, makros, large + phagein, to eat
Ingest cellular debris, pathogens
Key role in immune response
Help destroy tumor cells, invading
microgranisms (bacteria, protozoa)
• Type of WBC
– Derived from bone marrow
– Reside in tissue, monocytes migrate via blood
– Become marcrophages in tissue
Macrophages, cont.
• Integrates pathogen’s antigen into own cell
membrane
• Presents to other immune cells, causes
• Creation of antibodies
– Attach to antigen, destruction easier
• Releases many types of chemicals
– Enzymes
– Complement proteins
– Interleukin regulators
• Stimulate lymphocytes
Hypodermal Cells
• Mainly fat cells
• Cushioning layer
• Some fibroblasts & macrophages
Skin Tissues
• Each Layer of Skin has
different tissues with
different functions
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Epithelial
Collagen
Elastin
Reticulin
Follicles
Glandular
Nervous
Blood vessels
Fatty tissue
Epidermis Tissue
• Epithelial tissue only
• Protects all exposed areas of body organs
– Against Abrasion and injury
• Surfaces & lining of ducts/cavities
• Controls passage of material from outside
into organ’s cells
• Contains nerve fibers for sensory
awareness
Dermis
• 3 types of fibrous connective tissues
– Collagen, Elastin, Reticulin
• Strength, Firmness, Flexibility
• All arranged irregularly, haphazardly
• Allows skin to flex, stretch, contract when
stressed
Collagen
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One of most abundant proteins in body
Firmness
Connects and Supports body structures
Immense tensile strength
Elastin
• Helps keep skin flexible, tight
• Ability to bounce back
• Return to normal shape
Reticulin
• Protein fibers
• Crosslinked supportive meshwork for soft
tissue
Break Time
Dermis Accessory Tissues
• Specialized Epithelial Tissues (Exocrine)
– Sebaceous (Oil) glands
– Sudoriferous (Sweat) glands
• Hair follicles
• Nerves
Hair Structures
• Tricho- Gk: hair [thread; filament; condition
of the hair]
• Integrated with sebaceous glands
– Shaft = Hair above surface
• Cornified (dead) by time leaves surface
– Follicle = from matrix (bulb) in dermis
extending to surface at angle
– Erector Pilus = muscle attached to follicle
• Protects and decreases heat loss
Hair Structures
http://etc.usf.edu/clipart
Skin Muscles
• Arrector pili (sing.)
• Contraction
– Goose bumps/gooseflesh
– AKA Horripilation or cutis anserina L goose skin
– Caused by stimulus (cold or fear)
• Causes nerve discharge from sympathetic nervous
system, part of ANS (involuntary)
• nerve discharge causes contraction of arrectores
pilorum (hair erectors)
• Benefits ?
– Part of fight or flight reaction?
Types of Hair
• Lanugo
– soft downy hair covering fetus of some mammals
• Vellus hairs
– fine hairs appearing after lanugo hairs cast off
– persist until puberty
• Terminal hairs
– coarse hair on various areas of adult body
Hair Growth Cycle
• 3 Phases of the life of a hair
– Anagen (about ½ inch/month, about 5 years)
1st phase of hair cycle, in which synthesis of hair
occurs
– Catagen (2-3 weeks)
Transitional phase of hair cycle between growth and
resting of follicle
– Telogen
Resting phase of follicle in hair cycle
Hair cell growth
• The cells of hair bulb divide every 23 to 72
hours, faster than any other cell in body
• Chemotherapy and hair?
Gland tissue
• Sebum = oily substance
– Lipids
– Oils skin and hair
– Prevents drying/cracking
– Limits growth of bacteria
• Sweat
– Watery, has salts
– Cools body, Role in thermoregulation
– Delivers metabolic waste to surface
Sweat Glands
• 2 main types of sudoriferous or sweat glands
– Eccrine glands – (palms, soles, forehead)
• temperature control
– Apocrine glands - sweat, fats, proteins
• slightly more viscous sweat (scent glands)
• mainly present in armpits and around anogenital area
ears, hands, cheeks, navel, and areolas
• 2 other types of sudoriferous glands –
produce modified sweat
– Ceruminous glands - ear wax
– Mammary glands - milk
Nervous tissue
• Deep in dermis
• Many different types of sensory
receptors
• Perceive stimuli
• Transmit impulses to brain
Nerve Tissue
• Pacinian corpuscles
– Detect vibrations/heavy touch
• Meissner’s corpuscles
– Detect light touch
– Provide protection – painful/harmful
Nerve Tissue
• Ruffini corpuscle
– specialized sensory nerve organs in
skin & mucous membranes for
perceiving heat
• Krause corpuscle (end bulb)
– bulboid encapsulated nerve endings
located in mucous membranes and
activated by cold
• Free nerve ending
– receptor nerve ending NOT enclosed
in a capsule
Hypodermis Tissue
• Connective tissue
– Connects overlying epidermis/dermis to
underlying muscle
• Dermal appendages
– Hair, sweat and oil glands
• Blood vessels
• ANS nerves
• Fatty tissue
Skin and Aging
• Epidermis thins, although number of cell
layers remains unchanged
• Number of melanocytes decreases
• Remaining melanocytes get larger
• Large pigmented spots (age spots, liver
spots, or lentigos)
– may appear in sun-exposed areas
Skin and Aging
• Elastosis or Solar elastosis
– skin's strength and elasticity is reduced
• changes in connective tissue strength & elasticity
• Leathery, weather-beaten appearance
– Farmers
– Sailors
– Others
• Spend a large amount of time outdoors
• Tanning beds
Skin and Aging
• More fragile Dermal Blood vessels
– Bruising, bleeding under skin (often called senile
purpura), cherry angiomas, etc.
• Less oil produced by Sebaceous glands
– Men experience a minimal decrease
• usu. after 80
– Women gradually produce less oil at menopause
– May make it harder to keep skin moist
• Cause of dryness and itchiness
Skin and Aging
• Thinning of subcutaneous fat layer
– Reduces normal insulation and padding
– Increases risk of skin injury
– Reduces ability to maintain body temperature
– Increases risk of hypothermia in cold weather
• Less sweat produced by sweat glands
– Harder to keep cool
– Increases risk for becoming overheated
Skin and Aging
• Thinning skin reduces
– Ability to sense touch, pressure, vibration,
heat and cold
– Ability to repair itself
• Wound healing may be 4X slower
– Higher risk of injury
• Thinning skin increases
– Risk of pressure ulcers
Skin and Aging
• MOST skin changes are related to SUN
exposure
• PREVENTION is important throughout life
Nails
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Nails
• Nail plate
– Emerges from proximal nail fold, bordered either
side by lateral nail folds (paronychium)
– Hard, keratinized, squamous cells loosely
adherent to germinal matrix
– Strongly attached to sterile matrix
• Nail fold
– Most proximal aspect of perionychium
– Composed of dorsal roof & ventral floor
– Found approximately 15 mm distal to DIP
Nail fold
• Dorsal roof rests above forming nail
– Houses cells that give shine to nail
• Ventral floor lies beneath nail
– Immediately distal to insertion of extensor tendons
– Site of germinal matrix
– Responsible for 90% of nail production
• Eponychium
– Skin proximal to nail that covers nail fold
• Cuticle
– Tissue distal to eponychium in contact w/nail
Lunula
• Half-moon shaped white arc
– Proximal to distal on nail
• Distal extent of germinal matrix
• Characteristic color change
– Due to persistence of nail cell nuclei in germinal
matrix
• Distal to this location
– Nuclei absent
– Nail transparent
Sterile matrix
• Area of nail bed distal to lunula
• 2ndary site of nail production
• Tightly adherent to
– Nail plate
– Periosteum of distal phalanx
Hyponychium
• Junction formed bet. sterile matrix & fingertip
skin beneath nail margin
– Susceptible to contamination from environmental
interactions
– Keratin plug acts as mechanical barrier to protect
against infectious innoculation
• Has polymorphonuclear leukocytes & lymphocytes
• Contributing immunologic barrier to mechanical barrier
Nail Blood Supply
• Perionychium
– Arterial blood supply from terminal branches of
radial & ulnar proper palmar (volar) digital arteries
– These originate proximal to metacarpophalangeal
joint from common palmar digital arteries
• Proper palmar digital arteries
– Branch proximal to DIP joint
– Have branch that travels dorsal to DIP joint
– Supplies superficial arcade that feeds nail fold &
proximal matrix
Nail anatomy
Section of last bone of finger
5, Fat, forming the cushion at the end of the finger
2, The nail 1, The cuticle continued under and around the
3 Root of the nail
Breast
• ICD -9/10-CM – part of Reproductive
System Chapter
• CPT – part of Surgery/Integumentary
System Section
Female Breast
http://training.seer.cancer.gov/breast/anatomy/
Male Breast
http://www.cancer.gov/images/cdr/live/CDR694414-750.jpg
Breast Anatomy
• Located in upper ventral region
– Over pectoralis major muscles
– Extends from 2nd to 6th rib
– Superior lateral quadrant extends diagonally
upwards into axillary area
• To Tail of Spence
• AKA Spence's tail, axillary process, axillary tail
• James Spence (1812-1882), Scottish surgeon
– Thin layer of mammary tissue
• From clavicle to 7th/8th rib
• From midline to edge of latissimus dorsi posterior
Breast Quadrants
• For clinical purposes, the breast is divided
into four quadrants
• Upper inner
• Upper outer (largest)
• Lower inner
• Lower outer
Breast Tissue
• Breast is a combination of
– Lactiferous (milk-producing) ducts
– Connective tissue
– Adipose tissue
– Cooper's ligaments
• help support the breast
Breast Anatomy
• Blood supply
– Internal thoracic (internal mammary) artery
– Lateral thoracic, thoraco-acromial and
posterior intercostals arteries
• Blood drainage
– Axillary, internal thoroacic, & intercostal veins
• Nerves
– Anterior/lateral cutaneous branches of 4th -6th
intercostal nerves
Breast Components
• Contains mammary glands
– Various sizes, distributed thru out breast
– Modified sweat glands
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Nipple and areola
Connective tissue
Adipose tissue
Cooper ligaments
Nipple
• Nipple surrounded by areola
– Drainage point for lactiferous ducts
– Each duct has own opening
– Large # of blood vessels
– Large # of nerves
• Erection in response
– Sexual stimuli
– Cold
– Touch
– Enabled by nerve and blood supply
Areola
• Areola
– varies in color – pink to dark brown
– Contains sebaceous glands
• Mammary glands and milk
– Milk at back of breast
– Suckling makes smooth muscles of mammary
glands to be pushed to ducts, and then to
nipple
– 15-25 openings in nipple
Breast lymph nodes
• Lymph travels from
breast to
– Ipsilateral axillary
lymph nodes
– Parasternal nodes
– Other breast lymph
nodes
– Abdominal lymph
nodes
• Axillary lymph nodes
– Pectoral
– Subcapsular
– Humeral
• Central axillary, then
to Apical axillary
Breast growth
• Due to changing sex hormones (puberty)
– Estrogen
• Pregnancy changes
– Larger, firmer – hypertrophy of mammary glands
• Prolactin hormone
– Nipples may enlarge, become darker
• Menstrual cycle
– Also may cause breast/nipple changes
Homework
• Test Your Anatomy IQ – 12 questions
– http://www.webmd.com/healthy-beauty/rmquiz-anatomy
• Integumentary System. Quizlet.
– http://quizlet.com/806630/integumentarysystem-flash-cards/
• Skin, Hair, Nails. Quizlet.
– http://quizlet.com/6233503/skin-hair-nails-chp10-flash-cards/
imueller@email.wcu.edu
Resources
• Alaiti, S. Hair Anatomy. MedScape.
– http://emedicine.medscape.com/article/835470overview#showall
• Aging changes in skin. MedlinePlus.
– http://www.nlm.nih.gov/medlineplus/ency/article/
004014.htm
• Anatomy and Function of the Female Breast.
Breast Cancer Causes, cures, and biology.
– http://www.celtnet.org.uk/cancer/breastfunction.html
Resources
• Arens, E A, & Zhang, H. 2006. The skin's
role in human thermoregulation and
comfort. Center for the Built Environment,
University of California, Berkeley.
– http://escholarship.org/uc/item/3f4599hx
• The Body’s Protective Cover. National
Geographic. (Interactive review of skin)
http://science.nationalgeographic.com/scienc
e/health-and-human-body/human-body/skinarticle/
Resources
• California Dept. of Public Health. Anatomy
and Pathology. Breast Cancer Review.
– http://qap.sdsu.edu/education/bcrl/Bcrl_anatp
ath/bcrl_anatpath_index.html
• Definition of Arrectores pilorum.
MedicineNet.com
– http://www.medterms.com/script/main/art.asp
?articlekey=6856
Resources
• Markey, Sean. 20 things you didn’t know
about skin. Discover, 2/2007
– http://discovermagazine.com/2007/feb/20-things-skin/
• Niyonsaba, F. et.al. Antimicrobial Peptides
Human β-Defensins and Cathelicidin LL-37
Induce the Secretion of a Pruritogenic Cytokine
IL-31 by Human Mast Cells. The Journal of
Immunology April 1, 2010 vol. 184 no. 7 35263534
– http://www.jimmunol.org/content/184/7/3526.full
Resources
• Philips, B. Z., et. al. Nail Anatomy.
MedScape.
– http://emedicine.medscape.com/article/1948841overview#a1
• Vitamin D: Dietary Supplement Fact Sheet. NIH.
Office of Dietary Supplements.
– http://ods.od.nih.gov/factsheets/VitaminDHealthProfessional/
Videos
• Components of skin. MedlinePlus.
– http://www.nlm.nih.gov/medlineplus/ency/anat
omyvideos/000029.htm
• What is skin? The layers of human skin.
Clinuvel http://www.clinuvel.com 3.48
minutes video
– http://www.youtube.com/watch?v=yKAzVC0W
cmI&feature=related
Videos
• The Integumentary System - The Derivatives of the
Integumentary System. Rapid Learning Center.
9.21 minute video.
– http://www.youtube.com/watch?v=nRH8MarC58&feature=channel&list=UL
• The Integumentary System - What is Histology?
Rapid Learning Center. 2.40 minute video.
– http://www.youtube.com/watch?v=wrJwOoNdd1I&feature
=relmfu
Videos
• The Integumentary System - What's the
Epidermal Layer of the Skin? Rapid Learning
Center. 7.44 minute video.
– http://www.youtube.com/watch?v=R7_arNsaxPs&feat
ure=related
• The Integumentary System - What is the Dermal
Layer of the Skin? Rapid Learning Center. 8.30
minute video.
– http://www.youtube.com/watch?v=bmLxUnpdK9I&feat
ure=relmfu