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 The cutaneous membrane
 (SKIN), with various
 accessory organs, makes up
 the integumentary organs
Types of Membranes

 The three major types of epithelial
  membranes are serous, mucous, and
  cutaneous. These are usually thin
 Synovial Membranes we will discuss
  further in Ch 8; but they line joints
  and composed entirely of connective
  tissues, they contain no epithelium.
Serous Membranes
   Serous Membranes line the body cavities
    that lack openings to the outside and
    reduce friction between the organs and
    cavity walls.
   Consists of a layer of simple squamous
    epithelium and a thin layer of loose
    connective tissue.
Serous Membranes
   Cells of a serous membrane secrete water
    serous fluid, which helps to lubricate the
    surfaces of the membrane.
   They form the inner linings of the thorax
    and abdomen, and they cover the organs
    within these cavities.
Mucous Membrane
   Line the cavities and tubes that open to the
    outside of the body. These include the oral and
    nasal cavities and the tubes of the digestive,
    respiratory, urinary, and reproductive systems.
   Consists of epithelium overlying a layer of loose
    connective tissue (it can vary from location to
   Goblet cells within a mucous membrane secrete
Cutanous Membrane

   Is an organ of the integumentary
    organ system and is more commonly
    called skin. Which is what this
    chapter is about…..
   The skin is one of the largest and
    heaviest organ of the body. In an
    average adult, the skin covers about 2
    square meters (22 square feet), weights
    4.5-5 kg (10-11 lb) and varies in
    thickness (1.5 to 4.0 mm) depending on
    what part of the body it covers.
   The skin covers all of the exposed
    surface of the body and is continuous
    with the mucous membranes lining
    openings into the body surface, such
    as those of the digestive, respiratory
    and urogenital systems.
   The skin consists of 2 layers,
   - 1 - the outer epidermis, derived from the
    embryonic ectoderm and
   - 2 - the inner dermis which develops from the
   The appendages of the skin such as hair,
    nails, sebaceous glands and sweat glands
    develop from the embryonic epidermis.
   Beneath the dermis is the hypodermis
    (=subcutaneous tissue = superficial fascia)
    which anchors the skin loosely to
    underlying tissues (mainly muscles). The
    hypodermis is NOT part of the skin
   Epidermis is composed of stratified
    squamous epithelium, it lacks blood
   See Pg 154 ….the layers of the epidermis
    ranging from deepest to most superficial
    are Stratum basale, Stratum spinosum,
    Stratum granulosum, Stratum lucidum,
    and Stratum corneum.
   The stratum basale, is close to the dermis
    and is the only part of the epidermis that
    does have blood vessels. The cells of the
    stratum basale are well nourished, as the
    grow and enlarge they push older
    epidermal cells away from the dermis
    toward the surface of the skin. The further
    the cells travel the poorer their nutrient
    supply becomes.
   The older cells go through a process called
    keratinization which is when tough fibrous
    strands of waterproof keratin proteins are
    synthesized and stored within the cell
   As a result layers of tough, tightly packed dead
    cells accumulate in the epidermis; forming the
    stratum corneum. These cells will eventually
    shed off.
   In healthly skin the production of new skin
    cells usually balances with the loss of old
   The rate of cell division will increase in
    areas of the skin the undergo regular
    friction…causing calluses and corns.
   Melanocytes lie in the deepest section of
    the epidermis and in the underlying
    connective tissue…they are the only cells
    that produce melanin….however they
    sometime may be present in nearby
    epidermal cells.
   The boundary between the epidermis and
    dermis is usually uneven. This is because
    the epidermis has ridges projecting inward
    and the dermis has conical dermal
    papillae passing into the spaces between
    the ridges.
   Fingerprints form from these undulations
    of the skin.
   The dermis binds the epidermis to the
    underlying tissue.
   Composed of irregular dense connective
    tissue that includes tough collagenous
   Contains muscles fibers (some smooth
    some striated)
   Contains nerve fibers, moter fibers carry
    impulses to dermal muscles and glands,
    sensory fibers carry impulses away from
    specialized sensory receptors.
   One type of dermal sensory receptor,
    Pacinian corpuscles, is stimulated by
    heavy pressure. Meissner’s corpuscles,
    senses light touch.
Subcutaneous Layer
   Below the dermis; consists of loose connective
    and adipose tissue. No sharp boundary
    between dermis and subcutaneous layer.
   The adipose helps to provide insulation by
    conserving body heat. The amount various
    greatly from individual to individual and body
    part to body part. (abdominal v/s eyelids)
Subcutaneous Layer
   This layer contains the major blood
    vessels of that supply the skin.

   The skin and its appendages(hair,
    nails, sebaceous and sweat
    glands) make up a very complex
    set of organs that accomplishes
    several functions:
   - 1 - Protection: barrier against the outside
   - 2 - Protection against dehydration
   - 3 - Body Temperature Regulation
   - 4 - Cutaneous Sensation
   - 5 - Metabolic Functions
   - 6 - Blood Reservoir
   - 7 - Excretion
   The primary function of hairs is
    protection: in human, hairs protect the
    scalp from injury, from the sun ray and
    decrease heat loss. Eyebrows and
    eyelashes protect the eye from foreign
    particles. Hairs in the nostrils filter the
    air we inhale and hairs in the external
    ear canal also prevent foreign particles
    to penetrate there.
          Hairs are made of
           dead keratinized
   Usually grows for a time and then rests while it
    remains anchored in its follicle.
   A bundle of smooth muscle cells, forming the
    arrector pili muscle attaches to the hair follicle,
    the hair within the follicle stands on end when
    the muscle contracts. If a person is upset or
    cold nerve impulses may cause the arrector pili
    muscle to contract….aka goosebumps.
   Nails are hard plates      Nails protect the the
    of tightly packed           ends of the fingers,
    keratinized cells.          allow us to scratch
    They are clear and          various parts of our
    cover the dorsal            body and help us
    surface of the last         grasping and
    phalanges of fingers        manipulating small
    and toes.                   objects.

   Sebaceous glands or oil glands are
    simple branched areolar glands.
    Functionally they are holocrine
    glands. They secrete the sebum (seb
    = oil) an oily product.
   Sebum is usually           Sebum is a natural skin
    secreted into a hair        cream: it helps hair
                                from becoming brittle,
    follicle but in a few
                                prevents excessive
    regions of the body         evaporation of water
    (lips and mammary           from the skin, keeps the
    papilla for example)        skin soft and contains a
    they are directly           bacterial agent that
    secreted onto the           inhibits the growth of
    skin surface.               certain bacteria.

 Sebaceous   glands are scattered
 all over the surface of the skin
 except in the palms, soles and
 the side of the feet.

              Sweat glands or
               sudoriferous glands
               are simple coiled
               tubular glands. They
               are divided into two
               principal types:
               eccrine and
Sweat Glands- Eccrine
   Eccrine glands are the most
    common/numerous. Their secretory
    portion can be located in the dermis or in
    the hypodermis.
   They produce sweat, a watery mixture of
    salts, antibodies and metabolic wastes.
   Sweat prevents overheating of the body
    and thus helps regulate body temperature.
Sweat Glands- Eccrine
   Eccrine glands –respond throughout
    life to body temperature elevated by
    environmental heat or physical factors.
   Glands are common on the forehead,
    neck, and back.
   They also cause the moisture that
    appears on the palms and soles when a
    person is emotionally stressed.
Sweat Glands-Apocrine
   Apocrine glands are found mainly in the
    skin of the armpits, of the anogenital areas
    and of the areola of the breasts.
   May develop a scent as they are
    metabolized by skin bacteria (BO).
   Their excretory ducts open into hair
Sweat Glands-Apocrine

    Their secretion is more viscous than
     that of the eccrine glands.
    They start secreting at puberty and are
     also active during sexual arousal
    Can wet certain areas of the skin when
     a person is emotionally upset,
     frightened, or in pain.
Heat Production and Loss
   Because cellular           In intense heat nerve
    metabolism release          impulses stimulate
    heat, the most active       structues in the skin
    cells are the major         and other organs to
    heat producers,             release heat.
    skeletal and heart         The hypothalamus in
    muscle cells of             the brain controls the
    certain glands such         body set point for
    as the liver.               temperature.
Heat Production and Loss
   Major sources of heat         Convection- heat loss by
    loss in the body are           conduction to the air.
    Radiation-infrared heat
    rays escape from warmer       Evaporation- body
    surfaces to cooler.            temperature rises above
    (Primary means of body         normal, stimulates
    heat loss)                     eccrine sweat glands to
   Conduction-body heat           release sweat, as it
    moves directly from a          evaporates it carries the
    warmer surface to a            heat with it, cooling the
    cooler object in contact       skin.
    with its surfaces
Skin Color
   Regardless of racial orgin, all people have the
    same number of melanocytes in their skin,
    differences come from the amount of melanin
    these cells produce which in controlled by
   Environmental factors such as sunlight,
    ultraviolet light and x rays can effect the skin.
    The stimulate the melanocytes to produce more
    pigment which make you tan.
                 SKIN COLOR
   You will have to add the next few slides to
    your notes…NOT on the guided reading.

   Three pigments contribute to skin color
       Melanin
       Caroten
       Hemolgobin
               SKIN COLOR
   Melanin- A polymer ranging in color from
    yellow to reddish-brown to black
   Humans have relatively the SAME number of
    melanocytes, just depends on how much is
   Melanocytes are stimulated to greater activity
    when we expose our skin to sunlight
         SKIN COLOR

 Carotene- yellow to orange
  pigment. Found in carrots.
 Most obvious in the palms and
Skin Color
   Physiological               When Blood oxygen
    effect…when blood is         levels are low the
    well oxygenated the          hemoglobin is dark
    blood pigment                red, and the skin
    hemoglobin is bright         appears bluish– a
    red making the skin of       condition called
    fair complexioned            cyanosis.
    people appear
Healing of Wounds and Burns

 Skin,injuries trigger
 inflammation. The affected
 area becomes red, warm
 swollen, and tender.
   A cut in the                Granulations
    epidermis is filled in
    by dividing
                                 form as part of
    epithelial cells.            the healing
    Clots close deeper           process.
    cuts, sometimes
    leaving a scar where
    connective tissue
    replaces skin.
Superficial Partial-thickness (First
Degree Burns)
   A burn injuring only      Causes minor
    the epidermis.             discomfort and some
   Healing usually            reddening of the skin
    occurs within a few       No blistering occurs,
    days to two weeks.         No scarring and
   Ex: Minor sunburn          actual tissue
                               destruction is
Superficial Partial-thickness (First
Degree Burns)
(Deep) Partial-thickness (Second
Degree Burns)
   A burn that destroys         Not complete
    some deep epidermis           destruction of dermis
    as well as some               but often injuries
    underlying dermis.            include hair follicles,
   Most commonly occurs          sweat glands, and
    as a result of exposure       sebaceous glands.
    to hot objects, hot
    liquids, flames or           It blisters, scarring
    burning clothing.             occurs, severe pain,
   The area is moist and         and generalized
    firm, may vary in color       swelling.
    from dark red to waxy
Partial Thickness Burn
Partial Thickness Burn
(Deep) Full-thickness
(Third Degree Burns)
   A burn that is                Loss of nerve
    characterized by
    complete destruction of        endings cause an
    dermis and epidermis.          insensitivity to pain.
   Most commonly occurs          Often skin grafts are
    as a result of long
    exposure to hot
                                   used to try to repair
    objects, hot liquids,          loss tissue.
    flames, or chemicals.
   The area becomes dry
    and leathery, and it may
    vary in color from red
    to black to white.
Full Thickness Burn
Full Thickness Burn
               Electrical Burns
   In electrical injures the damage begins in
    the hypodermis and expands OUT.
              Electrical Burns
   Same injury days later…
Rule of Nines
   As an aid for estimating the extent of
    damage burns cause, the body is
    subdivided into regions, each represent
    9% ( or some multiple of 9%) of the total
    skin surface area.
Terms that are
NOT in your Book!!
   Pleurisy- a painful pathological condition
    characterized by inflammation of the
    serous membranes (pleura) that line the
    chest cavity and cover the lungs. Pain is
    caused by irritation and friction as the
    lungs rub against the walls of the chest
Terms that are
NOT in your Book!!
   Synovial membranes also line the small
    cushion-like sacs called Bursae.
   Strawberry hemangioma- a common collection
    of dilated vessels that may initially appear as a
    bruise at birth then grow rapidly during the first
    year into a bright red nodule.
   Any disorder of the skin is called dermatosis
   Dermatitis- inflammation of the skin

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