LECTURE 3 Histology

  1. adipose tissue
    a connective tissue characterized by the presence of large numbers of adipocytes (fat cells). Occurs subcutaneously, in the medullary cavities of bones, and elsewhere, serving as a stored source of body energy
  2. Apocrine secretion
    a secretory mode of glandular epithelium in which part of the cell physically breaks away to form the secretory product.  Apocrine secretion contrasts with merocrine (eccrine) secretion where no visible part of the cell enters the secretory product, and with holocrine secretion where cells die and slough to become the secretion
  3. basic tissue
    any on of four main categories of body tissue: epithelium, muscle tissue, connective tissue, and nervous tissue.  Except for nervous tissue, each category has is subdivided into specific tissues
  4. Biopsy
    removal of cells or tissue from a living organism, typically for lab analysis.  Common form of biopsy is blood sample
  5. blood
    a liquid connective tissue.  Only body liquid with a cell concentration high enough to deserve the label "tissue"
  6. bone marrow tissue
    major material occupying the medullary cavities of bones.  Is a subtype of connective tissue and called red bone marrow when actively hemopoietic; yellow bone marrow contains high population of adipocytes, and gelatinous bone marrow when it involutes with senility
  7. bone tissue
    a mineralized subtype of connective tissue.  only body material routinely mineralized ecept for the enamel, dentin, and cementum of teeth. Forms a major structure component of (the organs called) bones
  8. cartilage
    a connective tissue with a firm but typically unmineralized extracellular matrix.  divided into three subtypes based primarily on major type of proteinaceous fibers found in the matrix: elastic cartilage (containing elastic cartilage), fibrocartilage (containing collagenous fibrers), and hyaline cartilage (containing reticular fibers)
  9. connective tissue proper
    fibrous connective tissue, one of several subtypes of connective tissue.  Is the most widely distributed connective tissue and forms part of every organ
  10. extracellular matrix
    the material outside of and between cells.  In many tissues it includes various types of proteinaceous fibers as well as amorphous protein/polysaccharide material called ground substance
  11. Fiber
    a term used in various contexts to mean a muscle cell, a neuronal process, or a protein component of the extracellular matrix.  Proteinaceous extracellular fibers include those composed of elastin, collagen, and reticulin
  12. Glandular epithelium
    epithelium that is specialized for secretion. although glandular epithelial cells are scattered within the surface epithelium of mucous membranes, most glandular epithelium is concentrated in the secretory organs called glands
  13. ground substance
    the protein/polysaccaride component (glue) of the extracellular matrix.  The polysaccaride portion is often formed by polymers of chondroitin sulfate, keratin sulfate, and hyaluronic acid
  14. histology
    literally, the study of tissue. equivalent to microscopic anatomy which is science of minute structure of the body (cells, organelles, tissues, organs)
  15. membranous (surface) epithelium
    the tissue that forms all outer surfaces of the body and lines all of it's lumina and cavities.  Membranous epithelium is classified according to shape of the surface cells (squamous, cuboidal, columnar) and whether it is one cell thick (simple) or more than one cell thick (stratified)
  16. mesenchyme
    primitive connective tissue containing a large population of undifferentiated (stem) cells. Mesenchyme is concentrated in intervertebral discs and small amounts are present in the loose connective tissue around vessels
  17. muscle tissue
    the basic tissue functionally specialized for contraction.  three subtypes exist, skeletal muscle tissue (voluntary and striated), smooth muscle-tissue (involuntary, not striated) and cardiac muscle tissue (involuntary and striated
  18. Neuroglial (glial) cell
    a collective term encompassing the support cells of the nervous system. Neuroglia do not transmit impulses, but the support neurons physically and metabolically
  19. neuron (nerve cell)
    a cell specialized for impulse transmission. Each neuron has a single process termed the axon and one of more processes called dendrites
  20. primary germ layer
    any of the three defined strata that are formed during embryonic gastrulation: ectoderm, mesoderm, and endoderm.  These germ layers differentiate to form the various tissues
  21. regenerative capacity
    the ability of a given type of cell or tissue to replace itself if lost, injured or diseased.  Epithelium and connective tissue have high regenerative capacity, but nervous tissue and muscle tissue have low regenerative capabilities
  22. adipo-
  23. bio-
  24. chondro-
  25. dendr-
  26. derma-
  27. ekto-
  28. endo-
    within (endoderm)
  29. epi-
    upon, besides
  30. firbra-
    small fiber
  31. -glia
  32. histo-
  33. hyaline
  34. kerato-
  35. -klast
    to break
  36. kolla (colla)
  37. krinein (crine)
    to separate
  38. leuko-
  39. matrix
    the womb, origin
  40. meso-
    the middle
  41. para-
  42. patho-
    suffering, disease
  43. pseudo-
    false (pseudostratified)
  44. reticulatus
    netlike (reticulum)
  45. squamo
    scales (squamosal)
  46. tissues
    groups of similar cells and the extracellular matrix (products) in which they are embe3dded.
  47. matrix (def)
    typically produced (secreted) by the cells and may be liquid (as it is in blood), semisolid (as it in in cartilage), or quite hard (as in bone).
  48. ectoderm
    a primary germ layer, the outer layer, forms the outer epithelium and all of the nervous tissue in the body
  49. mesoderm
    a primary germ layer, the middle layer, forms all of the connective tissue, all of the muscle tissue, and the epithelium lining the vessels and serous body cavities
  50. endoderm
    a primary germ layer, inner layer, forms the lining epithelium of most parts of the visceral body systems
  51. Four basic tissues differ...
    structurally in the amount and type of intercellular material and in the capacity of the cells to proliferate (regenerate) after injury
  52. Muscle cells
    called myofibers (muscles fibers) or myocytes, they contain elongated contractile organelles in their cytoplasm called myofibrils.  produce very little intercellular matrix but each cell is invested with a delicate connective tissue sheath
  53. myofibrils
    composted of alternating stacks of proteins (actin, myosin, and others)
  54. skeletal muscle cells
    multinucleiated, nuclei are not centrally located, stratifed, cyendrical in shape, large. essentially have no regenerative capacity. totally dependent on it;s motor nerve supply
  55. cardiac muscle
    intercalated discs (jig saw looking things), striated, branched shaped. essentially have no regenerative capacity. centrally located nucleus. adjacent cells are joined ent to end by specialized structures call intercalated discs
  56. smooth muscle cells
    "spindle" in shape, so fatter in the middle. and pointed on ends like a football (fusiform). centrally located nucleus.  not layered. found within the walls of blood vessels, the walls of visceral organs, base of hair follicles, and within the iris and ciliary body of the eye.  In blood vessels, helps control BP. In visrceral organs, provides force that helps move materials through lumina. causes "goosebumps"
  57. myofilaments
    cause physical shortening (contraction) of the cells by sliding together
  58. intercalated discs
    specialized structures that joins cardiac muscle tissue end to end
  59. epithelial tissue
    epithelial tissue, covers inner and outer surfaces of the body (membranous epithelium) and forms secretory portions of the glands (glandular epithelium). have relatively small amount of intercellular matrix, remarkably high ability to regenerate.
  60. membranous epithelium
    sometimes called surface epithelium cause it covers outer surfaces and lines inner surfaces. Is avascular, aneural, and varies in thickness. Classified  in several categories based on thickness and shape of surface cells... however, only the shape of the cells at the surface is used when classifying. lacks blood vessels so exchanges nutrients and waste with adjacent tissues solely by diffusion
  61. Glandular epithelium
    forms the secretory portion (parenchyma) of glands, It is highly vascularized, innervated, and lacks a basement membrane. All glandular epithelium derive from membranous epithelium. manufactures a myriad of secretory products including sweat, milk, ear wax, skin oil, bile, pancreatic juice, mucus, saliva, sperm, ova... and others.
  62. basement membrane
    thin structure which separates membranous epithelium cells from the underlying tissues, consists of extracellular glycoprotein material which is manufactured by epithelial cells.
  63. simple epithelium
    epithelium tissue that is only one cell thick (one cell btwn the basement membrane and the surface or lumen) All cells make contact with the basement membrane
  64. stratified epithelium
    epithelium with two or more cell layers
  65. shapes of epithelial cells
    squamous (flattened), cuboidal (globular), or columnar (elongated)
  66. Pseudostratified columnar epithelium
    appears to be more than one cell thick because some cells are quite short and do not reach the surface, however since all cells are in contact with basement membrane, technically only one cell layer. This type lines the air conducting passageways of the respiratory system and is sometimes called "respiratory epithelium"
  67. Transitional epithelium
    lines the urinary bladder, ureters, and part of the urethra. appears to be composed of several cuboidal cells, but all cells make contact with basement membrane.
  68. Modifications that surface cells in membranous epithelia may possess
    Cilia, microvilli, and keratin
  69. cilia
    a modification surface cells in membranous epithelia may possess, relatively long projections that cells use to propel materials along the surface.  When cilia is present in epithelium, ciliated is added to the name
  70. microvilli
    a modification surface cells in membranous epithelia may posses, similar projections similar to cilia but much smaller, found in cells specialized for absorption. (singular - microvillus) cannot be moved by the cell. function is to increase surface area to facilitate absorption
  71. keratinization
    a modification the surface cells in membranous epithelia may posses, keratin is a dense protein manufactured by stratified squamous epithelium of the skin.  remains within cells but imparts physical strength and resistance to desiccation (drying)
  72. exocrine glands
    produce a variety of secretions, formed when glandular epithelium maintains a surface or lumen connection by being physically located at the surface or by having a duct that reaches a body surface
  73. endocrine gland
    secret hormones, formed when glands that lose all connections to the surface and secrete their products directly into the bloodstream. reserved for 5 glands that have no known function except hormone production
  74. goblet cells
    mucus producing unicellular exocrine glands within pseudostratified columnar epithelium in the respiratory passages and within the simple columnar epithelium of the intestinal glands.  Located at the surface so NO DUCT is needed to transport secretory product
  75. mixed glands
    secrete both exocrine and endocrine products
  76. modes of secretion of glandular epithelium
    Eccrine (merocrine), aprcrine, holocrine
  77. Eccrine (merocrine)
    one mode of secretion of glandular epithelium. Watery secretion, no structural parts of the secretory cells become part of the secretion
  78. Apocrine
    one mode of secretion of glandular epithelium, parts of secretory cells are lost into (become part of) the secretion
  79. Holocrine
    one mode of secretion of glandular epithelium, entire cells of the gland are lost into (become part of) the secretion
  80. connective tissue proper
    also called fibrous connective tissue, forms many structural parts of the body, present to some degree in essentially all organs. major kind is fibroblasts. Classified by fiber density, fiber arrangement, and major fiber type present.
  81. fibroblasts
    major form of connective tissue proper, secrete three kinds of fibers as well as ground substance of the matrix. Three kinds of fibers are collagenous fibers, elastic fibers, and reticular fibers.
  82. fibrocytes
    older fibroblasts that are relatively inactive
  83. collagenous fibers
    secreted from fibroblasts, composed of protein called collagen, relatively inelastic but are quite strong
  84. elastic fibers
    secreted from fibroblasts, composted of protein called elastin, have a rubber-band-like ability to stretch and return to their original shape
  85. reticular fibers
    secreted from fibroblasts, made of protein called reticulin, are structurally similar to very thin collagenous fibers,
  86. fiber density
    • (loose/dense) classification for connective tissue proper,subjective one referring to whether the fibers are packed tightly or have considerable space around them.
    • *loose connective tissue is always irregular. loose, regular tissue proper does not exist in the body. 
  87. fiber arrangement
    (regular/irregular) classification of CTP, criterion indicates whether the fibers are oriented in a relatively parallel manner (regular) or are not parallel to each other (irregular)
  88. fiber type
    classification for CTP, indicates which fiber type predominates, ( all three types are present to some degree in most fibrous connective tissue)
  89. bone tissue
    main structural component of the named bones of the body. Three cell types: osteoblasts, osteocytes, and osteoclasts
  90. osteoblasts
    type of bone tissue cell, secretes the fibers and ground substance. major fiber type secreted is collagenous fibers
  91. osteocytes
    type of bone tissue cell, are old osteoblasts which become entrapped in little cavities within the matrix called lacunae
  92. lacunae
    little cavities within the matrix of bone tissue that entrapp osteocytes
  93. osteoclasts
    type of bone tissue cell, multinucleated giant cells that reabsorb bone tissue
  94. cartilage
    has three cell types (chondroblasts, chondrocytes, and chondroclasts), matrix usually remains un-mineralized but is quite firm which keeps matrix from collapsing and forms lacunae around chondrocytes and chrondroblasts. mature cartilage is avascular and receives nutrition through diffusion. Three types of cartilage based on predominant fiber present: fibrocartilage, elastic cartilage, and hyaline cartilage
  95. chondroblast
    cell type of cartlage, immature chondrocytes, arise from mesenchyme and form extracellular matrix by secreting the fibers and ground substance
  96. chondroclast
    type of cartilage cell, giant cell that absorbs cartilage. present only in mineralized cartilage that is being removed as part of the endochondral ossification process
  97. fibrocartilage
    the dense collagenous fibers in the matrix impart strength and resistance to tearing and compression. Forms the outer parts of intervertebral discs, forms menisci with some of the joints, also present in the pubic symphysis which joins the two halves of the bony pelvis
  98. elastic cartilage
    has significant numbers of elastic fibers in the matrix which impart flexibility. found in the external ear and in parts of the larynx
  99. Hyaline cartilage
    has delicate collagenous (reticular) fibers within its matrix. matrix is clear (glassy) appearance. found on articular surface of bones where its often called articular cartilage. also forms costal cartilages of ribs, within trachea and bronchi, and some in larynx. most bones are formed first of hyaline cartilage and later become osseous. 
  100. Unlike bone tissue, once cartilage is formed...
    it is relatively static and has a very low turnover rate.
  101. blood
    only liquid tissue, has regular connective tissue components but ground substance is fluid because of high water content and because it's fibers remain soluble unless clotting mechanism is activated.
  102. erythrocytes & leucocytes
    red blood corpuscles (cells) & white blood cells
  103. adipose tissue
    connective tissue that contains large number of adipose (fat) cells. Occurs within subcutaneous tissues, within medullary cavities of many bones, also deposited within the connective tissue layer of peritoneum and pericardium. Serves as mobilizable stored energy
  104. reticular connective tissue
    contains reticulocytes which secrete reticular fibers. present in lymph nodes, spleen, thymus, etc
  105. bone marrow tissue
    type of connective tissue, occurs in the medullary cavities of many bones, consists of a myriad of blood cell precursor cells (hemocytoblast derivaties) interspersed in the frame work of reticular connective tissue
  106. mesenchyme
    also called primitive (undifferentiated) connective tissue, found around blood vessels and within intervertebral discs. can undergo rapid metaplasia and dirrerentiation when needed
  107. nervous tissue
    specialized for the conduction of electrical impulses, very little intercellular material, consists of neurons and several types of supporting cells termed neuroglia
  108. neuroglia
    supporting nerve cells found in nervous tissue
  109. neurons
    nervous tissue cells, so specialized they cant divide so injuries are often permanent. consists of central portion call the CELL BODY and two or more processes that conduct impluses. classified in basis of direction of impulse (toward body or away from body). classified by number and arrangement of their pocesses (multi- , bi- , or pseudounipolar)
  110. dendrites
    neuronal process which conduct impulses toward the cell bodies. Some neuron's only have one dendrite and some have several.
  111. axons
    neuronal processes which carry impulses AWAY from cell bodies.  Most neurons only have one axon but it may branch
  112. nerve fibers
    a collective term for the axonic and dendritic processes of neurons carrying sensory (incoming) information into the spinal cord and brain &&& the neurons transmitting motor (outgoing) information which is distributed to muscle and gland cells
  113. Neuroglia
    (neuroglial cells) include six types of supporting cells found in nervous tissue that don't conduct nervous impulses but perform a number of other functions
  114. scarring
    results from the proliferation of connective tissue proper after an injury
  115. histopathology
    the branch of medicine involved in the microscopic examination and evaluation of body tissues
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LECTURE 3 Histology