Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 5 ((Skin Functions (Protection (Physical Barrier (water loss,…

- - - - Physical Barrier
        
        water loss
        
        injury
        
        chemicals and microrganisms
      - Chemical Barrier
        
        pH or 5-6
        
        prevents microrganisms growth
      - Biological barrier
        
        Langerhans calls(epidermis)
        
        Macrophages and mast cells
    - - Urea
      - Uric acid
    - - Light touch detection-meisshers corpuscles
        
        egg shaped
        
        located in dermal papillae
        
        populate areas in the fingertips, palms,soles, eyelids,tip of tongue, nipples,clitoris, tip of penis
      - Pressure detection- pacinian corpuscles
        
        onion shaped
        
        Located in deep dermis and subcutaneous regions
    - - UV rays in sunlight activate its synthesis
      - Vitamin D is required for bone homeostasis
    - - the dermis houses about 10 percent of the bodys blood vessels
      - Skin only requires 1-2 percent of the bodys blood
    - - Langerhans cells
      - interacts with T-helper cells in immune responsees
- - - - most common forms of skin cancer
      - Orginates in stratum germinativum
    - - more superficial layers
    - - dangerous, usually begins as a mole
      - Metastasize thru the lymphoid system
- - - - Heat Production
        
        is mostly a by-product of cellular metabolism
      - Heat Loss- is controlled by regulating dermal blood flow
        
        Vasodilation- increases dermal blood
        
        vasoconstriction-decreases derma blood flow which decreases heat loss
      - Heat loss is by four methods
        
        Radiation
        
        most heat loss by this mode
        
        infrared heat rays move from area of high heat to areas of low heat
        
        Conduction
        
        less heat loss
        
        heat moves by physical contact
        
        the reason the seat you sit in is warm when you stand up
        
        Convection
        
        heat loss to surrounding air
        
        increases as air movement increases, that is why turning on a fan cools your body
        
        Evaporation
        
        heat loss varies
        
        if heat increases our sweating increases, so we lose more heat by evaporating the sweat on the surface of our skin
      - Low body temperatures require heat loss to be minimized
        
        the hypothalamus signals for sweating to decrease and dermal vasoconstriction
        
        Usually this brings the body temperature back to normal
      - If the body temperature remains low after the above action
        
        Heat must be produced
        
        shivering occurs and the tiny muscle contractions involved produce heat
    - - Hyperthermia- elevated body temperature
        
        humid air decreases evaporation
        
        air temperature exceeds body temperature, thus heat is gained not lost
      - hypothermia-low body temperature
        
        very dangerous if core body temperature drops below 94 degrees
        
        limbs can withstand about 65 degrees because they contain no vital organs
  - - - Epidermal cuts- are closed by increased cell division in the stratum basale
      - Deep cuts- involve blood vessel damage resulting in
        
        Step 1
        
        Inflamation
        
        Step 2
        
        scab, stem cells, phagocytes, and granulation tissue
        
        Step 3
        
        Stem cells move over mesh work from fibroblast, scab is disintegration
        
        Step 4
        
        scab is gone and a shallow depression is left
- - - - composed of dead epithelial cells filled with protein keratin
      - Stratum lucidum= translucent layer cells seperating s.corneum from s.granulosum
        
        Extra layer only in thick skin of soles and palms
    - - directly above basement membrane
      - composed of a single row mitosing cuboidal epithelial cells and composed of melanocytes
        
        specialized cells that produce the pigment melanin
    - - prevents moisture loss
      - prevents injury by penetration
      - prevents microorganisms/chemical entry
    - - determines skin color
      - is produced by melanocytes in stratum basale
- - - - fat
      - cellular material
    - - acne
      - seborrhea
  - - - Structure
        
        Coil in deep dermis
        
        Duct in dermis
        
        Pore at surface
      - Characteristics
        
        Respond to elevated temperature/ exersice
        
        No oder in secretion
        
        Function throughout life
        
        Not associated with hair follicles
        
        Location
        
        Forehead
        
        Neck
        
        Back
      - Secretion(merocrine)=99% water plus
        
        Salts and wastes(urea and uric acid
    - - Structure
        
        Duets terminate into hair follicles
      - Characteristics
        
        respond to stress/ emotions
        
        oder in secretions
        
        begin to function at puberty and continue through life
        
        associated with hair follicles
        
        Location
        
        armpits
        
        groin
      - Secretion(apocrine)+sweat above plus
        
        oil and cellular debris
      - Modified Apocrine gland
        
        Ceruminous glands=external ear secretion=earwax;cerumen
        
        Mammary glands=breast milk
- - - - Papillary layer
        
        composed of loose of loose areolar CT
        
        Surface forms dermal papillae that forms fingerprints in thick skin
        
        Meissner corpuscles(sensory receptor for light touch
      - Reticular layer=dense irregular CT
        
        Bundles of collagen fibers
        
        elastic fibers and reticular fibers which give skin its strength and resiliency
        
        Pacinian corpuscles- sensory recepters for deep pressure
- - - - adipose tissue and blood vessels
    - - insulation
- - - - Hair root or base in deep dermis
      - follicle throughout dermis
      - Hair Shaft in dermis
        
        cuticle outer shingle like layer
        
        Cortex middle layer, flexible soft keratin
        
        Medulia inner layer, hard keratin
    - - grows for 2-5 years/ new cycle pushes old hair out
      - .3 mm per day
      - 2.5 million on body/ 500,000 hairs on the head
    - - cells are epithelium
      - cells in root= active mitosis
      - cells in follicle= maturing and accumulating keratin
      - cells in epidermis=dead epithelial cells; full of keratin= exposed hair or hair shaft
    - - Genetically determined
      - White hair/ grey
        
        Lack of melanin and air bubbles
    - - peg of connective tissue
        
        Nerves and capillaries
    - - causes hair to stand on end when frightened or cold
- - - - manipulation; protection of digit ends
    - - nail body- covers the nail bed
      - nail root
        
        nail production by an epithelial fold
        
        lunula: pale crescent nail root
      - cuticle
        
        fold of stratum corneum (epinychium)