The Integumentary System - Get Now PowerPoint by 7m4ysl36

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									The Integumentary System
 Integumentary System
Organ - two or more kinds of
tissues grouped toghether and
performing specialized functions.
Skin is an organ composed of
sheetlike membranes of epithelium
and connective tissue.
            Types of Membranes
1.        Serous membrane
     a.    Line body cavities that lack
           openings to the outside.
     b.    Secrete serous fluid for
           lubrication.
     c.    Found in the inner lining of the
           thorax and abdomen.
            Types of Membranes
2.        Mucous Membranes
     a.    Line cavities and tubes that open to
           the outside of the body.
     b.    Secrete mucus
     c.    Found in oral and nasal cavities and
           tubes of digestive, respiratory,
           urinary and reproductive systems.
            Types of Membranes
3.        Synovial membranes
     a.    Form inner linings of the joint cavities
           between the ends of bones at freely
           moving joints (synovial joints)
     b.    Secrete thick, colorless synovial fluid
4.        Cutaneous membrane - the external
          body covering, SKIN
       The Functions of Skin
1.   Protective covering
2.   Regulates body temperature
3.   Slows water loss
4.   Contains sensory receptors
5.   Synthesizes biochemicals
6.   Excretes wastes
Skin and Its Tissues
              Epidermis
1.   Stratum basale - deepest layer of
     the epidermis, cells undergo
     mitosis.
2.   Keratinization occurs as cells are
     pushed towards the surface.
3.   Stratum corneum - outermost
     layer of dead cells.
              Epidermis
4.   Epidermis protects underlying
     tissues against water loss,
     mechanical injury, and effects of
     harmful chemicals.
5.   Melanin protects from UV light.
6.   Melanocytes transfer melanin to
     epidermal cells.
Epidermis

        Dead cells
        As cells are pushed
        up they become
        keratinized
            Basal cells
            undergoing
            mitosis
              Skin Color
1.   All people have about the same
     concentration of melanocytes.
2.   Skin color is due to the amount of
     melanin and the size of pigment
     granules in the epidermis.
3.   Skin color is influences by
     environmental and physiological
     factors as well as genes.
               Skin Color
4.   Albinism - genetic disorder
     characterized by no melanin, resulting
     in white skin and hair.
                 Dermis
1.   Binds the epidermis to the
     underlying tissues
2.   Contains blood vessels that
     supply all skin cells with nutrients
     and regulate body temperature.
                  Dermis
3.    Contains nerve fibers
     a.   May carry impulses to muscles
          and glands of the skin.
     b.   May be associated with sensory
          receptors in the skin.
4.    Contains hair follicles,
      sebaceous glands, and sweat
      glands.
       Subcutaneous Layer
1.   Loose connective and adipose
     tissue
2.   Conserves body heat.
3.   Contains blood vessels that
     supply the skin and adipose
     tissue.
Accessory Organs of the Skin
1.    Hair follicles
     a.   Hair develops from epidermal
          cells at the base of a tubelike
          hair follicle.
     b.   Cells are keratinized and
          pushed towards the surface as
          new cells are formed.
Accessory Organs of the Skin
Hair Follicles cont….
  c.   Smooth muscle cells attached to
       each follicle.
  d.   Hair color is determine by genes
       that determine how much
       melanin is produced.
Accessory Organs of the Skin
2.        Sebacceous Glands
     a.    Attached to hair follicles.
     b.    Secrete sebum (oily secretion)
           which keeps hair soft and water
           proof
     c.    Acne - infection of sebacceous
           glands
Accessory Organs of the Skin
3.        Nails
     a.    Protective covers on ends of fingers
           and toes.
     b.    Keratinized epidermal cells produce
           nails.
     c.    Keratin of nails is harder than that
           produced by the skin’s epidermal
           cells
Accessory Organs of the Skin
4.        Sweat Glands
     a.    Consists of a coiled tube.
     b.    Sweat - mostly water, also contains
           salts and waste products.
     c.    Eccrine sweat glands respond to
           elevated body temperature, while
           apocrine sweat glands respond to
           emotional stress.
       Regulation of Body
         Temperature
 Regulation of body temperature is
  vital because heat affects the rates
  of metabolic reactions.
 Normal body temperature is 37ºC
  (98.6ºF)
         Regulation of Body
           Temperature
1.   Increase in body temperature
     causes dermal blood vessels to
     dilate and sweat glands to secrete
     sweat.
2.   Decrease in body temperature
     causes dermal blood vessels to
     constrict and sweat glands
     become inactive.
        Regulation of Body
          Temperature
3.   Excessive heat loss stimulates
     skeletal muscles to contract
     involuntarily.
4.   Fever results from an elevated
     temperature set point.
         Healing of Wounds
1.   Inflammation - affected area becomes
     red, warm, swollen and tender.
2.   Dividing epithelial cells fill in shallow
     cuts.
3.   Clots close deeper cuts, sometimes
     leaving a scar where connective tissue
     replaces skin.
4.   Granulations form as part of the
     healing process.

								
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