Human Anatomy chapter 4

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  1. how many cells does the body have?
    75 trillion
  2. cells are organized into categories called?
  3. what is a tissue?
    is a group of cells performing similar functions
  4. what is extracellular matrix?
    • - a substance produced by the cells of a specific tissue and can contain protein, fibers, salts, water and dissolved macromolecules
    • - located outside the cells
  5. 4 types of tissues
    • - epithelial
    • - connective
    • -muscle
    • -nervous
  6. Epithelial Tissue
    • -lines every body surface and all the body cavities
    • -organs are lined on the outside and inside by epithelial tissue
    • -majority of the glands are derived from epithelial tissue
    • -possesses little to no extracellular matrix
  7. characteristics of epithelial tissues
    • -Cellularity
    • - polarity
    • - attachment
    • - avascularity
    • - innervation
    • - regeneration
  8. cellularity
    • - composed almost entirely of cells with little extracellular matrix.
    • - cells are bound together by several types of intercellular junctions
  9. polarity
    - epithelial cells have a apical (top or exposed ) surface and a basal surface where they attach to underlying cells
  10. attachment
    - basal surface is attached to a thin basement membrane, which us an acellular structure produced by both epithelial and underlying connective tissue cells
  11. Avascularity
    - all epithelial tissues lack blood vessels; the cells receive their nutrients by diffusion from underlying tissues
  12. innervation
    -epithelia are richly innervated to detect changes in environment at a body or organ region
  13. regeneration
    - because apical surface is constantly exposed to the environment, epithelial cell are frequently damaged or die; they are replaced as quickly as they are lost
  14. functions of epithelial tissues
    • -physical protection
    • -selective permeability
    • -secretions
    • -sensations
  15. physical protection
    - from dehydration and abrasion; and physical, chemical and biology agents
  16. selective permeability
    -regulates the passage of certain molecules in or out of a certain region of the body
  17. secretions
    - some epithelial cells called exocrine cells produce secretion such as sweat or oil
  18. sensations
    -possess nerve endings that can detect light taste sound, smell an hearing
  19. basement membrane
    • -foun between the epithelium and underlying connective tissue
    • - provides physical support and anchoring of epithelial tissue
    • -acts as a barrier to regulate passage of large molecules between epithelium and underlying connective tissue
  20. intercellular junctions
    -epithelial cells are strongly bound at each other on their lateral surfaces by sharing membrane specializations called intercellular junctions
  21. types of intercellular junctions
    • - tight junctions
    • - adhering junctions
    • - desmosomes
    • - gap junctions
  22. tight junctions
    • - also known as zonula occludens
    • - prevents molecules from traveling between epithelial cells, therefore molecules must go through the epithelial cells rather that in between them
    • - "gatekeepers" between and external and internal environment
  23. adhering junctions
    • - also known as zonula adherens
    • -formed completely around the cell deep in the tight junctions 
    • - microfilaments act like a purse string to stabilize the apical surface of the epithelial cell
  24. desmosomes
    • - like a button or snap between adjacent cells
    • -appear at locations of mechanical stress between cells sharing this types of junction
    • - consists of a thickened protein plaque on each of the apposed call membranes with a fine network of proteins spanning the intercellular space between the plaques
    • -on the cyctoplasmic side, intermediate filaments attach to the plaques and provide support and stability to this structure that is shared between the 2 apposed cells
  25. Gap junctions
    • - fluid-filled channels that directly connect the cytoplasm of apposed cells sharing these structure
    • -these structures all adjacent cell to communicate with each other by the flow of ions and other small molecule messengers
  26. Classifying epithelia
    • -many differnent types if epithelial tissue
    • - classified according to 2 criteria:
    •            - number of layers of cells   
    •            - shape  of the cells
  27. epithelia cell layers
    • - simple epithelium
    • -  stratified  epithelium
    • - pseudostratifed epithelium
  28. simple epthelial
    - a single layer if cells with all cell having an apical surface and attached to the basement membrane
  29. stratified epithelium
    2 or more layers of cell, not all cells have an apical surface nor do all cells attach to the basement membrane
  30. pseudostratified epithelium
    -single layer but not all cells reach the apical surface and their nuclei give the appearance of  multilayered, stratified epithelium .... but they are not
  31. epithelial cell shapes
    • - squamous
    • - cuboidal
    • - columnar
  32. squamous
    flattened and similar to the shape of a fried egg
  33. cuboidal
    about the same size on all sides, the nucleus is usually centrally located
  34. columnar
    taller than they are wide and nucleus is oval and located in the basal region of the cell
  35. types of epithelium
    • - to decide the type of epithelium, determine  how many layers are and what is the shape  of surface cells
    •         -start with  a single layer simple epithelium
    •          -then consider multiple layered stratified epithelium
  36. simple squamous epithelium
    single layer of flat cells
  37. simple cuboidal epithelium
    single layer of cube-shaped cells
  38. stratified squamous epithelium
    multiple layers of flattened cells
  39. stratified cuboidal epithelium
    multiple layers of cube-shaped cells
  40. stratified columnar epithelium
    multiple layers of cells the are taller than they are wide
  41. pseudostratified columnar epithelium
    single layer of columnar epithelial cell but layer appearance of nuclei suggest multiple layers of cells
  42. transitional epithelium
    • - found lining the side  the urinary bladder
    • - changes shape between squamous and cuboidal depending on whether bladder is full and its wall is stretched or empty and its wall is contracted
  43. glands
    • - perform a secretory function
    • - produce mucin, hormones enzymes and waste products
    • - fall into 2 categories
    •       - endocrine
    •       - exocrine
  44. endocrine
    glands do not possess ducts and secrete directly into  the interstitial fluid or the bloodstream, derived from multiple tissue
  45. exocrine
    glands possess ducts and their cells secrete their products into their ducts; almost all exocrine glands are derived from epithelial tissue
  46. connective tissue
    • - most diverse, abundant, widely distributed and structurally varied of all 4 tissues
    • -function to "connect" one structure to another structure
    • -CT is the "glue" and "filler" of the body
    • - examples: tendons, ligaments, body fat, bones and cartilage
  47. structural components of connective tissue
    • - cells
    • - protein fibers
    • - ground substance
  48. cells
    different cells for different types of CT-bone, cells, cartilage cells ,fat cells
  49. protein fibers
    elastic fibers, collagen, reticular fibers
  50. ground substance
    • a mixture of proteins and carbohydrates with variable amount of salts and water
    •       - the protein fibers and ground substance comprise the extracellular matrix, which is produced by the CT cells
  51. functions for connective tissue
    • -physical protection
    • - support and structural framework
    • - binding of structures
    • - storage
    • - transport
    • - immune protection
  52. Development of Connective tissue
    • - arises from mesoderm
    • - 2 types of embryonic CT
    •          - mesenchyme
    •          - mucous
  53. mesenchyme
    the source of all adult CT
  54. Mucous
    found in umbilical cord and can contain stem cells for future use y the individual
  55. classification of connective Tissue
    • CT types present after birth can be classified in to 3 broad categories
    •      - CT proper
    •      - supporting CT
    •      - fluid CT
  56. cells of connective tissue proper
    • there are 2 groups of cells in the CT proper
    • - resident cells
    • - wandering cells
  57. resident cells
    include  fibroblasts, adipocytes, fixed macrophages and mesenchymal cells
  58. wandering cells
    include mast, and plasma cells, free macrophages and leukocytes
  59. fibers of connective tissue proper
    • there are 3 general types if proteins fibers produced by CT cells and secreted into the extracellular matrix
    • - collagen fibers
    • -elastic fibers
    • -reticular fibers
  60. collagen
    • -long unbranching, strong, flexible and resistant to  stretching
    • - they make up 25% of all protein in the human body, making collagen the most abundant protein
  61. elastic fibers
    • -thinner than collagen, stretch easily, branch and rejoin.
    • -these fiber s allow structures such as blood vessels to stretch and relax
  62. reticular fibers
    • -thinner than collagen fibers, form a meshwork-like configuration
    • -they are found in organs with abundant spaces such as liver, lymph nodes and spleen
    • -act as packing material
  63. ground substance of connective tissue proper
    • -a combination of proteins and carbohydrates
    • -additional content such water and salts can result in a texture anywhere from semi-fluid (adipose, fat) to hard (bone)
  64. connective tissue proper
    • can be classified into 2 categories
    • -loose CT
    • -dense CT
  65. loose connective tissue
    has fewer protein fibers and more ground substance
  66. dense connective tissue
    has more protein fibers and less ground substance
  67. loose connective tissue
    • severs as the body's  packing material, found in spaces around organs; there are 3 times
    • -areolar CT
    • -adipose CT
    • -reticular CT
  68. areolar connect tissue
    • - contains fibroblasts collagen and elastic fibers
    • - can be distorted without damage
    • - found subcutaneous to skin, surrounds nerves and bv
  69. adipose connective tissue
    known as "fat", comprised mainly of adipocytes (fat cells) and little else
  70. reticular connective tissue
    • - contains reticular fibers, fibroblasts and leukocytes
    • - found in spleen, lymph nodes and bone marrow
  71. dense connective tissue
    • - strong has fibers (mostly Collagen) packed tightly together   
    • - there are 3 types
    •      - dense regualr connective tissue
    •      - dense irregular connective tissue
    •      - elastic connective tissue
  72. dense  regular connective tissue
    • - collagen fibers aligned parallel to applied force
    • - found in tendons (attaché muscle to bone) and ligaments (attach bone to bone)
  73. dense irregular connective tissue
    • -bundles of collagen fibers extending in many directions
    • - found in deep portion of the skin (dermis) and capsules around organs such as the liver, kidney and spleen
  74. elastic connective tissue
    • -predominant elastic fibers provide ability to stretch and recoil
    • - found in the vocal cords and large/medium arteries
  75. supporting connective tissue
    • 2 types
    •    - cartilage
    •    - bone
  76. cartlige
    • -cells are called chondrocytes. they secret a gel-like extracellular matrix containing collagen and elastic fibers
    • - chondrocytes occupy small spaces enclosed by their extracellular matrix called lacunae
    • -they provide support and withstand deformation 
    •         -for  example, the nose and the ear

  77. types of cartilage
    • -hyaline cartilage
    • -fibrocartilage
    • -elastic cartilage
  78. hyaline cartilage
    • - most common type but the weakest
    • -found in fetal skeleton, at ends of bones that articulate with each other, in trachea, larynx and nose
  79. fibrocartilage
    • -supporting connective tissue
    • - densely interwoven collagen fibers contribute to the durability
    • -found in intervertebral disc, pubic symphysis and the menisci of the knee
    •        - acts as shock absorber
  80. elastic cartilage
    • -supporting connective tissue
    • -elastic fibers are main feature
    • - found in epiglottis and external ear
    •       - both structures need to bend and snap back to original form
  81. bone
    • -cells are called osteocytes
    • - extracellular matrix is an unique mixture of collagen and bone salts
    • - this mixture provides extreme strength (from the bone salts) and micro-flexibility (from the collagen)
  82. fluid connective tissue
    • comprised of the following components
    •  - plasma
    •  - erythrocytes
    •  - leukocytes
    •  - platelets
  83. plasma
    watery ground substance containing protein fibers
  84. erythrocytes
    red blood cells
  85. leukocytes
    white blood cells
  86. platelets
    fragment of blood cells involved in blood clotting
  87. muscle tissue
    • -comprised of cells called fibers
    • - when stimulated by the nervous system, fibers shorten or contract
    • - the result of contraction is movement (i.e., movement of bones blood, food sperm)

  88. classification of muscle tissue
    • - skeletal
    • - cardiac
    • - smooth
  89. skeletal muscle
    • - attached to bones of skeleton and some skin
    • - cells (muscle fibers) are:
    •       - cylindrical and long (some as long as whole muscle)
    •       - multinucleated
    •       - striated (striped internal appearance) and voluntary
    • - contraction causes movement of skeleton or skin
  90. cardiac muscle
    • - found only in the wall of the heat (myocardium)+
    • - cells are:
    •      - branched, Y-shaped, shorter than skeletal fibers cells
    •      - striated and involuntary
    •      - attached end-to-end by strong gap junctions call intercalated discs that allow rapid passage of electrical current from one cell to the next during each heat beat
    • - contraction cause movement of blood
  91. smooth muscle
    • -found in wall of most internal organs
    •     - stomach, intestines , uninary bladder
    • - cells are :
    •     - relatively short, wide in the middle, and tapered at the ends (fusiform)
    •      - involuntary and non-striated
    • - contraction causes movement of food, blood , sperm
  92. nervous tissue
    • - contains 2 types of cells
    •     - neurons
    •     - neuroglia
    • - function is communication and control body functions
  93. neurons
    - nerve cells that are capable of initiating and conducting electrical activity throughout the body
  94. neuroglia
    cells that support the neurons
  95. tissue change and aging
    • tissue can undergo change in form, size or number during the aging process;
    •   - metaplasia: epithelia lining the respiratory  airways of people who smoke change from pseudostratifed ciliated to stratified squamous
    •    - hypertrophy-  an increase in the size of existing cells
    •    - hyperplasia- an increase in the number of cells in a tissue
    •    - neoplasia - out-of-control growth, which forms a tumor 
    •    -atrophy - shrinkage of tissue by cell size or number
Card Set
Human Anatomy chapter 4
Tissues, junctions, bones, glands
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