Anatomy Ch 5

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Anatomy Ch 5
2010-09-27 18:05:21
Anatomy Integumentary System

Notes from Anatomy ch 5 Integumentary System
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  1. Integumentary System
    Skin and accessory structures - hair, nails, glands, muscles, nerves
  2. Two parts of skin
    • Epidermis - contains epithelial tissue
    • Dermis - contains connective tissue
  3. cutaneous membrane
    • skin
    • largest organ in both surface area and weight
  4. subcutaneous (subQ) layer
    also called the hypodermis
    • deep to the dermis - not part of the skin
    • consists of areolar and adipose tissue
    • storage depot for fat - large blood vessels that supply the skin
  5. lamellated (pacinian) corpuscles
    • nerve endings in the subcutaneous layer that are sensitive to pressure
  6. keratinocytes
    • majority of cells in the epidermis
    • produce keratin
    • produce lemellar granules - release a water-repellent sealant that decreses water entry and loss

    keratin is a tough protein that helps protect the skin and underlying tissue
  7. melanocytes
    • produce melanin - pigment - yellow-red or brown-black
    • melanin absorbs damaging UV light
    • melanocytes produce melanin and secrete it to the keratinocytes in granular form
    • melanin shields keratincytes from UV light
    • 8% of epidural cells
  8. Langerhans cells
    • involved in immune response - flag pathogens for other cells to destroy
    • start in red bone marrow - migrate to epidermis - small amount
  9. Merkel cells
    • specialized cell type - work in conjunction with nerves to detect touch sensation
    • tactile (Merkel) disk - the sensory neuron that the Merkel cells work with
  10. thin skin
    • skin on most regions of body
    • Has four strata:
    • 1. stratum basale
    • 2. stratum spinosum
    • 3. stratum granulosum
    • 4. thin stratum corneum
  11. thick skin
    • skin where exposure to friction is great - fingers, soles of feet
    • No sabaceous glans and no hair folicles
    • Sudoriferous glands (sweat glands) are present
    • Has 5 layers:
    • Stratum Basale
    • Stratum spinosum
    • stratum granulosum
    • stratum lucidum
    • thick stratum corneum
  12. Layers of the epidermis (deep to superficial)
    • made of keratinized stratified squamous epithelium
    • 1. Stratum Basale - single layer
    • 2. stratum spinosum - 8 to 10 layers
    • 3. stratum granulosum - 3 layers
    • 4. stratum lucidum -thick skin - 3 -5 layers
    • 5. stratum corneum - 25-30 layers
  13. Stratum Basale
    • deepest layer of epidermis
    • also called stratum germinativum - single layer
    • mitotic division - one cell stays anchored and the other moves superficially to surface of skin
  14. stratum spinosum
    • keratinocytes - second deepest layer
    • live cells
    • look spiny when separated because of intermediate filaments connecting cells via desmosomes
  15. tratum granulosum
    lemellar granules
    • mix of dead and live cells
    • flattened keratinocytes undergoing apoptosis (programmed cell death)
    • keratinocyes - lemellar granules - secrete water-repellent sealant that decreses water entry and loss
    • keratohyalin - protein that converts tonofilaments (internediate filaments) into keratin
  16. Stratum lucidum
    • only in thick skin - dead keratincytes that have a large amount of keratin - tough cells
    • no sebatious glands or hair folicles
  17. stratum corneum
    • most superficial layer of epidermis
    • dead, flat, keratin filled - waterproofed
    • continuously shed and replaced by deeper cells
  18. kerainization
    • accumulation of keratin in cells as they move from one epidermis layer to the next
    • undergo apoptosis and slough off after dead and keratinized
    • Takes 4 weeks for cell to travel from stratum basale to stratum corneum and slough off
  19. Epidermal growth facor (EGF)
    hormone-like protein that regulates epidermal cell division rate and increases it when epidermis is damaged
  20. dermis
    • deeper part of skin - composed of connective tissue
    • blood vessels, nerves, glands, and hair follicles in this layer
    • composed of:
    • 1. papillary region
    • 2. reticular region
  21. Papillary region
    Dermal papillae
    Epidermal ridges
    Meissner corpuscles
    Free nerve endings
    • the most superficial of two regions of connective tissue in the dermis
    • 20% of dermal layer
    • Areolar CT
    • Dermal papillae - nipples - project into epidermis - cause epidermal ridges
    • Epidermal ridges - ridges on epidermis - fingerprints
    • Meissner corpuscles - corpuscles of touch - tactile receptors in dermal papillae that are sensitive to touch
    • Free nerve endings - dentrites (receptor part of neuron) that lack structural specialization - initiate signals that give rise to sensations of warmth, coolness, pain, itching
  22. Reticular regions
    • part of the dermis - attached to the subcutaneous layer
    • dense irregular CT
    • contains collagen and elastic fiber that give skin extensibility and elasticity
    • extensibility - ability to stretch
    • elasticity - ability to return to original shape after stretching
  23. melanosome
    organelle of melanocytes that synthesize melanin
  24. nevus
    mole - round, flat, or raised area - results form an overgrowth of melanocytes
  25. hemoglobin
    • carrier protein RBC
    • oxygen-carrying pigment in red blood cells
    • when highly oxigenatied give red or pink color to skin - pale people done have enough melanin to cover it
  26. carotene
    • yellow- orange pigment that gives egg yolks and carrots color
    • precursor of vitamin A
  27. Albinism
    • albinos have normal amount of melanocytes - not producing melanin at all
    • vitiligo - lack of melanocytes
  28. cyanotic
    • skin turns blue
    • not enough oxygen in blood (stopped breathing)
    • blood moves to organs and away from skin (cold)
  29. jaundice
    • skin looks yellow
    • buildup of yellow pigment bilirubin - liver disease - liver not removing bilirubin from blood
  30. erythema
    • skin looks red
    • incresed blood flow to area due to skin injury, exposure to heat, infection, inflammation, allergic reaction
  31. pallor
    • pale skin
    • shock and anemia
  32. pili
    • Hair
  33. shaft
    hair follicle
    epithelial root sheath
    • shaft - superficial portion of hair that projects above surface of skin
    • root - portion of hair deep to the shaft - pentrates into dermis
    • hair follicle - surrounds the root of the hair - made of external root sheath and internal root sheath - together called the epithelial root sheath
  34. Dermal root sheath
    papilla of the hair
    • dense dermis surrounding the hair follicle
    • bulb - base of each hair follicle - onion-shaped structure
    • papilla of the hair - nipple-shaped indentation in the bulb - areolar CT and blood vessels that nourish growing hair follicle
    • matrix - in the bulb - stratum basale - responsible for growth of hair
  35. arrector pili
    muscle which contracts under physiologic or emotional stress causing the hair shaft to be perendicular to the skin surface - goose bumps
  36. hair root plexuses
    dentrites of neurons that surround each hair follicle - sensitive to touch
  37. lanugo
    vellus hair
    terminal hair
    • lanugo - fine hair covering the body of the fatus - shed before birth
    • vellus hairs - short fine hair that covers body (infancy through adulthood)
    • teminal hair - thick coarse hair - head, face, pubic areas
  38. alopecia
    • alopecia - partial or complete lack of hair - caused by genetic factors, aging, endocrine disorders, chemotherapy, skin disease
    • hirsutism - a condition of excessive body hair
  39. sebaceous gland
    • oil glands - epithelial cells that secrete sebum
    • usually connected to and opens into a hair follicle
    • Sebum - oily substance that coats hairs to keep from drying - also covers skin to stop excessive evaporation of water, inhibits growth of certain bacteria, keeps skin soft and pliable
  40. sudoriferous glands
    two types of sweat glands
    • sweat glands - three to four million in body - release perspiration into hair follicles or onto skin surface
    • 1. Eccrine sweat gland
    • 2. Apocrine sweat glands
  41. Eccrine sweat glands
    • most regions of body - esp forehead, palms, soles
    • simple, coiled tubular glands - deep dermis - terminates at surface of epidermis
    • Regulates body temp, waste removal
    • functions soon after birth
  42. Apocrine swear glands
    • axilla (armpit), groin, areolae, beard
    • simple, coiled tubular glands - subcutaneous layer - terminates in hair follicle
    • emotional stress & sexual excitement
    • funtions at puberty
  43. insensible perspiration
    sensible perspiration
    • insensible perspiration - sweat that evaporates before it is perceived
    • sensible perspiration - sweat excreted in larger amounts and is seen as moisture on the skin
  44. ceruminous glands
    • sweat glands in external ear - produce a waxy secretion
    • cerumen - earwax -combined secretions of ceruminous and sebaceous glands
  45. Nails
    • plates of tightly packed, hard, dead, keratinized epidermal cells
  46. 7 Parts of the nail
    • 1. Nail body - visible portion
    • 2. free edge - extents past distal end of digit
    • 3. nail root - buried in a fold of the skin
    • 4. lunula - little moon - white area caused by thicker nail in that area
    • 5. hyponychium - secures nail to fingertip
    • 6. eponychium - cuticle - narrow band of epidermis that expands from and adheres to the margin of the nail wall
    • 7. nail matrix - deep to the nail root - mitosis to produce nail growth
  47. Functions of Hair
    • reduce heat loss
    • protects eyes, nose, ears
    • senses light touch
  48. Functions of Skin
    • 1. Thermoregulation - via sweat glands and modified blood flow
    • 2. Protection - from heat, dehydration, microbes - langerhans cells, microphages
    • 3. Cutaneous sensations - cold, hot, pressure, pain
    • 4. Excretion and Absorption -excretes water, ammonia, urea - absorbs lipid soluble vit A, D, E, K, cortizone, toxins
    • 5. Synthesis of Vit D - liver and kidneys use UV rays to prodice calcitriol - hormone that aids in absorbtion of calcuim
  49. Blood resevor
    dermis houses extensive newwork of blood vessels - carry 8-10% of total blood flow
  50. Epidermal wound healing
    contact inhibition
    epidermal injury - basal cells around wound break contact with basement membrane and migrate across wound until they encounter one another - contact inhibition causes them to stop migrating
  51. Deep wound healing
    four phases of wound healing
    granulation tissue
    • wound that extends to dermis and subcutaneous layer
    • 1. inflammatory phase - blood clot forms and loosely unites edge of wound
    • 2. migratory phase- clot becomes scab, epithelial tissue migrate under scab to bridge wound. Tissue filling the wound is called granulation tissue
    • 3. proliferative phase - extensive growth of epithelial cells beneath scab
    • 4. maturation phase - scab sloughs off - blood vessels restored to normal
  52. inflammation
    vascular and cellular response that helps eliminate microbes, foreign material, and dying material in prep for repair
  53. Fibrosis
    Hypertrophic scar
    keloid scar
    • process of scar tissue formation
    • Hypertrophic scar - a scar that remains within the boundaries of the original wound
    • keloid scar - scar tissue that extends beyond the bounderies into normal surrounding tissue