1. Epidermis
    Keratinized stratified squamous epithelium
  2. Dermis
    Connective tissue layer
  3. Hypodermis
    Subcutaneous fat layer
  4. Functions of the Skin (6)
    • Resistance to trauma and infection
    • Barrier to ultraviolet light
    • Vitamin D synthesis
    • Sensory receptors
    • Thermoreceptors through sweating
    • Nonverbal communication
  5. Stem Cells
    Undifferentiated cells in deepest layers
  6. Keratinocytes
    Most of the skin cells
  7. Melanocytes
    Synthesize pigment that shield UV
  8. Tactile (Merkel) Cells
    Receptor cells associated with nerve fibers
  9. Dendritic (Langerhans) Cells
    Macrophages guard against pathogens
  10. Stratum Basale
    • Single layer of cells on basement membrane
    • Keratinocyte stem cells undergo mitosis to replace epidermis
    • Melanocytes distribute melanin through cell processes and melanin picked up by keratinocytes
    • Merkel cells are touch receptors that form Merkel disc
  11. Stratum Spinosum
    • Several layers of keratinocytes
    • Appear spiny due to shrinkage during histological preparation
    • Contains denditic (langerhans) cells
    • Macrophages from bone marrow that migrate to the epidermis
    • Help protect body against pathogens by presenting them to the immune system
  12. Stratum Granulosum
    • 3 to 5 layers of flat keratinocytes
    • Contain keratinohyalin granules which combine with filaments of cytoskeleton to form keratin
    • Produces lipid-filled vesicles that release a glycolipid by exocytosis to waterproof the skin
    • It forms a barrier between surface cells and deeper layers of the epidermis and cuts off surface strata from nutrient supply
  13. Stratum Lucidum
    • Thin translucent zone seen only in thick skin
    • Keratinocytes are packed with eleidin, a precursor to keratin (does not stain well)
    • cells have no nucleus or organelles
  14. Stratum Corneum
    • Up to 30 layers of dead, scaly, keratinized cells
    • Surface cells flake off (exfoliate)
  15. Dermal Papillae
    • Extensions of the dermis into the epidermis
    • Forms the ridges of the fingerprints
    • Layers: Papillary layer, reticular layer is deeper part of the dermis
  16. Hemoglobin
    Red pigment of red blood cells
  17. Carotene
    • Yellow pigment
    • concentrates in stratum corneum and fat
  18. Melanin
    • Yellow, Brown, and Black hues
    • Pigment synthesis stimulated by UV radiation
  19. Cyanosis
    Blueness from deficiency of oxygen in the circulating blood (cold weather)
  20. Erythema
    Redness due to dilated cutaneous vessels (anger, sunburn, embarrassment)
  21. Jaundice
    Yellowing of skin and sclera due to excess of bilirubin in blood (liver disease)
  22. Hemangiomas
    Birthmarks: discolored skin caused by benign tumors of dermal blood capillaries (strawberry birthmarks disappear in childhood while port wine birthmarks last for life)
  23. Freckles and Moles
    • Aggregations of melanocytes
    • Freckles are flat
    • Moles are elevated
  24. Friction ridges
    • Leave oily fingerprints on touched surfaces
    • A unique pattern formed during fetal development
  25. Flexion Creases
    form after birth by repeated creasing of the hand, wrist, and elbow areas
  26. Hair Shaft
    Above skin
  27. Root
    • Within follicle
    • Medulla, Cortex, and Cuticle
  28. Follicle
    Oblique tube within the skin
  29. Bulb
    Where hair originates
  30. Papilla
    Vascular tissue in bulb that provides nutrients
  31. Blonde Hair
    • Little Eumelanin
    • Mostly Pheomelanin
  32. Black Hair
    All Eumelanin
  33. Red Hair
    • Little Eurmelanin
    • Lots of Pheomelanin
  34. White hair
    Lack of pigment and hollow
  35. Sudoriferous Glands
    Sweat Glands
  36. Apocrine
    • Produces scent of sweat
    • Found only near hair follicles and respond to stress and sex
    • Bromhidrosis is body odor produced by bacterial action on fatty acids
  37. Merocrine (Eccrine)
    • Produces persperation
    • Millions of them help cool the body
  38. Sebaceous Glands
    • Produce Sebum, an oily secretion that contains broken-down cells.
    • Lanolin is sebum
  39. Polythelia
    Additional nipples that may develop along milk line
  40. Basal Cell Carcinoma
    • Least dangerous
    • Arises from stratus basale and invades dermis
  41. Squamous Cell Carcinoma
    • Arises from keratinocytes in stratum spinosum
    • Metastasis to the lymph nodes can be lethal
  42. Malignant Melanoma
    • Most deadly
    • Arises from melanocytes of a preexisting mole
    • ABCD: asymmetry, border irregular, color mixed and diameter over 6 mm
  43. Autograph
    Tissue from patient
  44. Isograft
    Tissue from identical twin
  45. Hemograft (allograft)
    From unrelated person
  46. Heterograft (Xenograft)
    from another species
  47. Calcium Phospate
    Minerals that harden the matrix of connective tissue
  48. Long Bones
    Lever acted upon by muscles
  49. Short Bones
    Glide across one another in multiple directions
  50. Flat Bones
    Protect soft organs
  51. Shaft (Diaphysis)
    • Cylinder of compact bone
    • Marrow cavity lined with endosteum
  52. Marrow Cavity
    Medullary Cavity
  53. Endosteum
    Osteogenic cells and reticular connective tissue
  54. Epipheses
    • Enlarged ends
    • Spongy bone covered by compact bone
    • Enlarged to strengthen joint and attach ligaments
  55. Joint Surface
    Covered with articular cartilage
  56. Shaft
    • Covered with periosteum
    • Outer layer fibrous layer of collagen
    • Inner osteogenic layer of bone forming cells
  57. Epiphyseal plate
    Growth plate
  58. Structure of a Long Bone
    • Compact and Spongy Bone
    • Marrow Cavity
    • Articular Cartilage
    • Periosteum
  59. Structure of a Flat Bone
    • External and internal surfaces composed of compact bone
    • Middle layer is spongy bone and bone marrow
    • Skull fracture may leave inner layer of compact bone unharmed
  60. Fibroblasts
    Bone stem cells
  61. Osteogenic Cells
    • in endosteum, periosteum, or central canals give rise to new osteoblasts
    • Arise from embryonic fibroblasts (bone stem cells)
    • Multiply continuously
  62. Osteoblasts
    Mineralize organic matter of a matrix
  63. Osteocytes
    • Osteoblasts trapped in the matrix they formed
    • Cells in lacunae connected by gap junctions inside canaliculi
  64. Osteoclasts
    • Develop in bone marrow by fusion of 3-50 blood stem cells
    • Reside in resorption pits that they "eat" into the bone
  65. Dry Weight of Osseous Tissue Matrix
    1/3 organic and 2/3 inorganic
  66. Organic Matter
    collagen, glycosaminoglycans, proteglycans and glycoproteins
  67. Inorganic Matter
    • 85% hydroxyapatite (calcium phosphate)
    • 10% minerals (fluoride, potassium, magnessium)
  68. Osteon
    • Basic structural unit
    • Cylinders formed from layers of matrix around central canal
    • Osteocytes connected to each other and their blood supply by tiny cell processes in canaliculi
  69. Lamellae
    Layers of matrix around central canal
  70. Osteonic Canal
    Central canal
  71. Volkmann Canals
    • Perforating canals
    • Vascular canals perpendicularly joining central canals
  72. Trabeculae
    • plates of bone that give spongy bone spongelike appearance
    • Have few osteons or central canals
    • No osteocyte is far from blood of bone marrow
    • Develop along bone's lines of stress
  73. Bone Marrow
    In medullary cavity (long bone) and among trabeculae (spongy bone)
  74. Medullary Cavity
    Long Bone
  75. Trabeculae
    Spongy Bone
  76. Red Marrow
    • Like thick blood
    • Reticular fibers and immature cells
    • Hemopoietic (Produces blood cells)
    • In vertebrae, ribs, sternum, pelvic girdle and proximal heads of femur and humerus in adults
  77. Yellow Marrow
    Fatty marrow of long bones in adults
  78. Gelatinous Marrow of Old Age
    Yellow marrow replaced with reddish jelly
  79. Intramembranous Ossification
    • Condensation of mesenchyme into trabeculae
    • Osteoblasts on trabeculae lay down osteoid tisssue (uncalcified bone)
    • Calcium phosphate is deposited in the matrix forming bony trabeculae of spongy bone
    • Osteoclasts create marrow cavity
    • Osteoblasts form compact bone at surface
    • Surface mesenchyme produces periosteum
    • Produces flat bones of skull and clavicle
  80. Osteoid Tissue
    Uncalcified Bone
  81. Osteoclasts in Intramembranous Ossification
    Create marrow cavity
  82. Osteoblasts in Intramembranous Ossification
    Form compact bone at surface
  83. Endochondral Ossification
    • Bone develops for pre-existing model; perichondrium and hyaline cartilage
    • Most bones develop by this process
    • Formation of primary ossification center and marrow cavity in shaft of model
    • Stem cells give rise to osteoblasts and clasts
    • Bone laid down and marrow cavity created
  84. Osteoblasts
    Develop bony collar
  85. Chondrocytes
    Swell and die in Enchondral ossification
  86. Cartilage in Endochondral Ossification
    Remains as articular cartilage and epiphyseal (growth) plates, which proved grown through childhood and are gone by early twenties
  87. Zone of Reserve Cartilage
    Hyaline Cartilage
  88. Zone of Proliferation
    Chondrocytes multiply forming columns of flat lacunae
  89. Zone of Hypertrophy
    Cell enlargement
  90. Zone of Calcification
    Mineralization of matrix
  91. Zone of Bone Deposition
    • Chondrocytes die and columns fill with osteoblasts
    • Osteons formed and spongy bone is created
  92. How Bones Increase in Length
    • Interstitial growth and epiphyseal plate
    • Epiphyseal line is left behind when cartilage is gone
  93. How Bones Increase in Width
    • Appositional Growth
    • Osteoblasts lay down matrix in layers on outer surface and osteoclasts dissolve bone on inner surface
  94. How Bones are Remodeled Throughout Life
    • Wolff's Law of Bone
    • Greater Density and mass of bone in athletes or manual workers is an adaptation to stress
  95. Wolff's Law of Bone
    • Architecture of bone determined by mechanical stresses
    • Action of osteoblasts and osteoclasts
  96. Mineralization
    • Crystallization process
    • Osteoblasts produce collages fibers spiraled the length of the osteon
    • Minerals cover the fibers and harden the matrix
    • Ions are deposited along the fibers
    • Ion concentration must reach the solubility product for crystal formation to occur
  97. Ions
    Calcium and phosphate and from blood plasma
  98. Ectopic
    • Abnormal calcification
    • May occur in lungs, brain, eyes, muscles, tendons, or arteries (arteriosclerosis)
  99. Mineral Resorption from Bone
    • Bone dissolved and minerals released into blood for other uses
    • Performed by osteoclasts "ruffled border"
    • Hydrogen pumps in membrane secrete hydrogen into space between the osteoclast and bone surface
    • chloride ion follow by electrical attraction
    • hydrochloric acid dissolves bone minerals
    • Enzyme digests collagen
  100. Acid Phosphatase
    Enzyme that digests the collage in mineral resorption from bone
  101. Dental Braces
    • Stimulates osteoclasts to remove bone
    • Decrease pressure stimulates osteoblasts
  102. Phosphate
    Component of DNA, RNA, ATP, phospholipids, and pH buffers
  103. Calcium
    Needed in neurons, muscle contraction, blood clotting and exocytosis
  104. Ion Imbalances
    • Phosphate level change = little effect
    • Calcium level change = can be serious
    • Homeostasis depends on calcitriol, calcitonin, and PTH hormon regulation
  105. Hypocalcemia
    • Deficiency of blood calcium
    • Causes excitability of nervous system if too low
    • Muscle spasms, tremors, or tetany 6 mg/dl
    • Laryngospasm and suffocation 4 mg/dl
  106. Hypercalcemia
    • Excess of blood calcium
    • Binding to cell surface makes sodium channels less likely to open, depressing nervous system
    • Muscle weakness and sluggish reflexes, cardiac arrest 12 mg/dl
  107. Axial Skeleton
    • Central axis
    • Skull, vertebral column, ribs, sternum and sacrum
  108. Appendicular Skeleton
    Limbs and girdles
  109. Pectoral Girdle
    Scapula and clavicle
  110. Sternoclavicular and Acromioclavicular Joint
    Clavicle attaches medially to the sternum and laterally to the scapula
  111. Humeroscapular
    • Should joint
    • Scapula articulates with the humerus
    • easily dislocated due to loose attachment
  112. Brachium
    Arm = Humerus
  113. Antebrachium
    Forearm = Radius and ulna (Radius is on the thumb side)
  114. Carpus
    Wrist = 8 small bones in 2 rows
  115. Manus
    • Hand = 19 bones in 2 groups
    • 5 metacarpals in palm
    • 14 phalanges in fingers
  116. Carpal Bones
    • Form the wrist
    • Allow for flexion, extension, abduction and adduction
    • 2 Rows/4 Bones Each
    • - Proximal row = scaphoid, lunate, triquetrum and pisiform
    • -Distal row = trapezium, trapezoid, capitate and hamate
  117. Phalanges
    Proximal, middle and distal phalanx
  118. Metacarpals
    Base, shaft, and head
  119. Girdle
    2 Hip Bones
  120. Pelvis
    Girdle and Sacrum
  121. Pelvic Girdle
    • Supports trunk on the legs and protects viscera
    • Each os coxae is joined to the vertebral column at the sacroiliac joint
    • Anteriorly, pubic bones are joined by pad of fibrocartilage to form pubic symphysis
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