1. Histology
    Microscopic structure and composition of tissues
  2. Histopathology
    Study of both healthy and diseased tissue
  3. Histopathologist
    A person who specialized in the study of both healthy and diseased tissue
  4. Epithelial tissue
    • sheets of cells that cover all of the internal and external surfaces of the body and line all of the bodys cavities
    • *Digestive tract, urinary tract and blood vessels*
    • protect underlying tissues and may act to filter biochemical substances
    • may absorb, secrete or excrete biochemical substances
    • may play a role in the reception of sensory input
  5. Characteristics of Epithelia
    • Each epithelial cell has an apical surface and a basal surface *apical surface faces the lumen or outside of the organ, basal surface faces the basal lamina and blood vessels*
    • Lateral surfaces are connected to neighboring cells by junctional complexes
    • Epithelial cells are avascular
    • Most epithelial cells are innervated
  6. Cellular attatchments
    • Tight juntions
    • Desmosomes
    • Gap junctions
  7. Tight Junctions
    • Formed by the fusion of the outermost layers of the plasma membranes of adjoining cells
    • Found in tissues which there can be no leaks (urinary bladder, digestive tract)
  8. Gap Junctions
    • Tubular channel proteins (connexons) that extend from the cytoplasm of one cell to the cytoplasm of another
    • Allow the exchange and passage of ions and nutrients
    • Found in intestinal epithelial cells, the heart and smooth muscle tissue
  9. Basement Membrane
    • Meshwork of fibers that cements the epithelial cell to the underlying connective tissue
    • Also called the basal lamina
    • Varies in thickness
    • Helps prevent the cell from being torn off by intraluminal pressures
    • Acts as a partial barrier between the epithelial cell and the underlying connective tissue
  10. Surface Specialization
    • Surfaces of epithelial cells vary depending on where they are located and what role they play in the function of the tissue
    • Smooth
    • microvilli (brush border)
    • cillia
    • keratin
  11. Classification of epithelial tissue
    • number of layers of cells *simple or stratified*
    • shape of the cells *squamous, cuboidal and columnar*
    • presence of surface specializations*cillia, keratin, etc.*
  12. Simple Squamous Epithelium
    • fragile and thin
    • found in the lining surfaces involved in the passage of either gas or liquid *lung, kidney*
    • flat and smooth
  13. Simple Cuboidal Epithelium
    • single layer of cube-shaped cells
    • round, dark-staining nuclei aligned in a single row
    • occurs in areas of the body where secretion and absorption take place*ovaries, thyroid, lining of ducts of the liver, pancreas, kidney, and salivary glands*
  14. Simple Columnar Epithelium
    • Elongated and closely packed together
    • nuclei aligned in a row at the base of the cell near the basement membrane
    • found in may excretory ducts as well as the digestive tract
  15. Stratified Squamous Epithelium
    • Multilayered
    • occurs in areas of the body subject to mechanical and chemical stresses *lining of the mouth, esophagus, vagina and rectum*
    • protects the underlying tissues
  16. Stratified Cuboidal Epithelium
    • usually two layers of cuboidal cells
    • found primarily along large excretory ducts*sweat glands, mammary glands,salivary glands*
    • protects underlying tissues
  17. Stratified Columnar Epitheium
    • sound only in select parts of the respiratory, digestive, reproductive systems and along some excretory ducts
    • functions in secretion and protection
  18. Pseudostratified Columnar Epithelium
    • cell nuclei are found at different levels across the length of the tissue
    • some cells do not reach the luminal surface
    • found in respiratory tract and in protions of the male reproductive tract
    • *look like multi layered, they are not, still one layer*
  19. Transitional Epithelium
    • stratified epithelium with a basal layer of cuboidal or columnar cells and a superficial layer of cuboidal or squamous cells
    • found in areas of the body required to expand and contract as part of their normal function*bladder, urethra,ureters, calyxes of the kidney*
  20. Glandular Epithelium
    • groups of cells that manufacture and discharge a secretion
    • classification of glands is by
    • 1- presence or absence of ducts,
    • 2- number of cells that compose them, 3-shape of the secreting ducts,
    • 4-complexity of the glandular structure,
    • 5-type of secretion they produce
    • 6-manner in which the secretion is stored and discharged
  21. Endocrine Glands
    • glands that do NOT have ducts or tubules and whose secretions are distributed throughout the body
    • produce and secrete hormones into the bloodstream or lymphatic system
    • part of a complex biochemical network know as the endocrine system
  22. Exocrine glands
    • discharge secretions via ducts directly into local areas (except for the goblet cell)
    • unicellular or multicellular
  23. Goblet Cell
    • unicellular exocrine gland
    • ductless and composed of modified columnar epithelial cell
    • found among columnar cells of the respiratory and digestive tracts and the conjunctiva of the eye
    • secretes mucin - thick, sticky mixture of glycoprotiens and proteoglycans = mucus
    • mucus functions in 2 ways, protect the apical surface of the epithelial layer and entrapment of microorganisms and foreign body
  24. Multicellular Exocrine Glands
    • composed of a secretory unit and a duct
    • secretory unit is usually surrounded by connective tussue rich in blood vessels and nerve fibers
    • may be surrounded by myoepithelial cells that assist with the discharge of secretions into the glandular duct
  25. Classification of Exocrine Glands
    • ducts
    • -simple:the main duct in unbranched
    • -compound:the main duct is branched
    • shape of secretory portions
    • -tubular:secretory cells form a long channel of even width
    • -alveolar or acinar:secretory init forms a rounded sac
    • -Tubuloalveolar or tubuloacinar:secretory units posses both tubular and alveolar qualities
  26. Classifications of exocrine glands
    • merocrine glands package their secretions and release them via exocytosis as they are manufactured (the cells remain intact, only secrete at the top) pancreas, sweat glands, and salivary glands
    • Apocrine glands store their secretions and then release the top part of the cell into the duct system(mammary tissue)
    • Holocrine glands store their secretions and then release the entire contents of the cell, the entire cell is destroyed -move from the basal layer up (sebaceous glands)
  27. Types of secretions produced
    • serous secretions
    • -watery
    • -contain a high concentration on enzymes
    • mucous secretions
    • -thich, viscous
    • -compound of glycoproteins
    • mixed exocrine glands contain both mucous and serous components
  28. Connective tissue Functions
    • forms metabolic and structural connections between other tissues
    • forms a protective sheath around organs and helps insulate the body
    • acts as a reserve for energy
    • provides the frame that supports the body
    • composes the medium that transports substances from one region of the body to another
    • plays a role in the healing process and in the control of invading microorganisms
  29. Connective tissue components
    • extracellular matrix = extracellular fibers and ground substance
    • cells
  30. Connective tissue components = Ground substance
    • medium through which cells exchange nutrients and wast with the bloodstream
    • amorphous, homogenous material
    • ranges in texture from a liquid or gel to a calcified solid
    • acts to protect the more delicate cells in envelopes
    • serves as an affective obstacle for invading microorganisms
  31. Serous Membranes
    • they line the walls and cover the organs
    • the portion that lines the cavity wall = parietal
    • the portion that covers the outer surface of the organs = visceral
  32. Serosal Fluid
    its a transudate = able to pass through into the narrow spaces between the serosal layers
  33. Transudate in the...
    • thorax = pleural fluid
    • abdomen = peritoneal fluid
    • heart = pericardial fluid
  34. Exudate
    when cells, protein and other solid material mix with serous fluid, it becomes denser than a transudate
  35. Effusion
    large amount of fluid enters a body cavity
  36. Ascites
    effusion in the peritoneal space in the abdomenopelvic cavity
  37. Extracellular fibers - collagenous fibers
    • strong, thick strands of collagen
    • organized into bundles of long, PARALLEL fibrils composed of bundled microfibrils
    • variable density and arrangement of fibers
    • found in tendons and ligaments
  38. Extracellular fibers- reticular fibers
    • thin, delicate, branched network of collagen
    • provide support for highly cellular organs(endocrine glands, lymph nodes, spleen, bone marrow and liver)
    • also found around blood vessels, nerves, muscle fibers and capillaries
  39. Extracellular fibers - elastic
    • branched networks composed primarily of the protein elastin
    • composed of coiled bundles of microfibrils
    • occur in tissue commonly subjected to stretching (vocal cords, lungs, skin, walls of blood vessels)
  40. Connective Tissue Cell types
    • Fixed cells = involved in the production and maintenance of the matrix (fibroblasts, chondroblasts, osteoblasts,adipocytes and reticular cells)
    • Transient cells = involved in the repair and protection of tissue (leukocytes, mast cells, macrophages)
  41. Wandering Cells - cells that move in and out of connective tissue as needed
    • 3 common types are...
    • leukocyes
    • mast cells
    • macrophages
  42. Wandering cells
    • leukocytes: found in blood and move into connective tissue in large numbers
    • although larger than RBC, they squeeze through the walls of tiny blood vessels to enter the tissue - diapediesis
  43. Wandering cells:
    • Mast cells: oval cells that are easily identified by the large dark-staining granules stored in the cytoplasm
    • these granules contain histamine and heparin
  44. Wandering Cells:
    • Macrophages: massive, irregular shaped phagocytizing scavangers
    • engulf microbes, dead cells and debris that are subsequently digested in the macrophages lysosomes
    • drawn to sites of infection and inflammation
  45. Kupffer cells
    liver macrophages
  46. Microglial cells
    brain macrophages
  47. Histocytes
    connective tissue macrophages
  48. Loose Connective Tissue
    • Areolar
    • Adipose
    • Reticular
  49. Dense Connective Tissue
    • Dense regular
    • Dense irregular
    • Elastic
  50. Areolar Connective Tissue
    • loose connective tissue
    • fibers and cells suspended in a thick, translucent ground substance
    • predominent cells is the fibroblast
    • fibroblast manufactures the elastic, reticular and collagenous fibers
    • surrounds every organ; forms the SQ layer that connects skin to muscle; envelopes blood vessels, nerves and lymph nodes; present in all MM
  51. Adipose Tissue
    • loose connective tissue
    • areolar tissue in which adipocytes predominate
    • highly vascular
    • acts as an energy storehouse and a thermal insulator
  52. Reticular Connective Tissue
    • loose connective tissue
    • network of thin reticular fibers and mainly fibroblasts suspended in a supportive ground substance
    • forms the stroma (framework of several organs)
  53. Dense Regular Connective Tissue
    • composed of tightly packed, paralled collagen fibers
    • relitively avascular
    • makes up tendons and ligaments
    • can be found in fascial sheets that cover muscle
  54. Dense Irregular Connective Tissue
    • Composed primarily of collagen fibers arranged in thick bundles
    • fibers are interwoven to form a single sheet
    • found in the dermis of the skin and in the fibrous coverings of many organs
    • forms the tough capsule of joints
  55. Elastic Connective Tissue
    • primarily composed of elastic fibers
    • fibers may be arranged paralled or in interwoven patterns with fibroblasts and collagenous fibers interspersed
    • found in spaces between vertebrae and in areas of the body that require stretching (walls of arteries, stomach, bronchi and bladder)
  56. Specialized Connective Tissue
    • Cartilage - hyaline, elastic, fibrocartilage
    • Bone
    • Blood
  57. Cartilage
    • found in joints and in the ear, nose and vocal cords
    • forms a framework on which bone is formed
    • Cells: chondrocytes live in the hollowed out pockets in the matrix called lacunae
    • Matrix: ground substance is a gel made up of chondoitin sulfate, hyaluronic acid and chondronectin
    • collagen fibers are most commonly found in the matrix, but elastic fibers are also present in varying amounts
  58. Hyaline Cartilage
    • most common type of cartilage found in the body
    • compsed of closely packed collagen
    • found in joints at the ends of long bones, growth plates of long bones, tracheal rings and connections of the ribs to the sternum
    • composes most of the embryonic skeleton
    • enclosed within a perichondriium
  59. Elastic Cartilage
    • contains elastic fibers in dense branching bundles
    • flexible and can withstand repeated bending
    • found in the epiglottis of the larynx and in the pinnea of the ears in animals
  60. Fibrocartilage
    • usually found merged with hyaline cartilage and dense connective tissue
    • contains thick bundles of collagen fibers with fewer chondrocytes than hyaline cartilage
    • lacks a perichondrium; found in spaces between vertebrae of the spine, between bones in the pelvic girdle and int he knee joint
  61. Bone
    • matrix is a combination of organic collagen fibers and inorganic calcium salts
    • well vascularized
    • haversian canal contains both a vascular and a nerve supply
    • canaliculi are channels within the matrix that supports passage of blood vessels into deeper portions of tissue
    • osteoblasts manufacture the fibers that are part of the matirx
    • Lacunae and canaliculi are created as the osteoblasts manufacture the bony matrix
    • osteocytes reside in the lacunae
    • cellular extensions pass through the cabaliculi
  62. Blood
    • Matix = ground substance = plasma, fibrous component = protein
    • Cells = erythrocytes, leukocytes, thrombocytes
  63. Mucous Membranes = Mucosae
    • line organs with connections to the outside environment ( mouth, intestines, nasal passages)
    • usually composed of either stratified squamous or simple columnar epithelium covering a layer of loose connective tissue
    • submucosa is the connective tissue layer that connects the mucosa to underlying structures
    • may contain goblet cells or multicellular glands; can produce large quantites of mucus
    • some mucosae also can absorb (the epithelial layer in the intestines)
  64. Serous Membranes = Serosae
    • line walls and cover organs of the body cavities (thorax and abdomen)
    • consists of a continuous sheet doubled over on itself to form 2 layers)
    • the portion of the membrane that lines the cavity wall is called the PARIETAL layer
    • the portion of the membrane that covers the outer surface of organs is called the VISCERAL layer
    • in abdominopelivic cavity, visceral layers of serosa merge to form mesenteries
  65. Cutanous Membrane
    • also called integument (skin)
    • composed of an outer keratinized stratified squamous epithelium or epidermis
    • epidermis is attatched to an underlying layer of dense irregular connective tissue called the dermis
    • dermis contains collagenous, reticular and elastic fibers which enable skin to be both strong and elastic
  66. Synovial Membranes
    • line the cavities of joints
    • composed of loose connective tissue and adipose tissue covered by a layer of collagen fibers and fibroblasts
    • manufacture the synovial fluid that fills the joint spaces
  67. Muscle Tissue
    • composed of actin and myosin fibers
    • 3 types of muscle tissue; skeletal, smooth, cardiac
  68. Skeletal Muscle
    • large cells that contain hundreds of nuclei and mitochondria
    • usually controlled through conscious efforts (VOLUNTARY MUSCLE)
    • skeletal muscle cells are striated
    • skeletal muscle cells are bundles of fibers held together by loose connective tissue
    • the collagen fibers that surround the cells merge with the collagen fibers in tendons
  69. Smooth Muscle
    • composed of small, spindle - shaped cells that lack striations
    • muscle contractions cannot be consciously controlled (NONSTRIATED, INVOLUNTARY MUSCLE)
    • found in walls of hollow organs, in endocrine glands and alongh the respiratory tract
    • responsible for peristalsis in the GI tract, constrictions of blood vessels and emptying the urinary bladder
  70. Cardiac Muscle
    • found only in the heart
    • contains specialized pacemaker cells that supply the signal for the heart to contract at regular intervals
    • cardiac muscle cells connected to one another by intercalated disks (intercellular junctions)
  71. Nervous Tissue
    • found in the brain, spinal cord and peripheral nerves
    • composed of 2 general cell types; neurons and supporting neuroglial cells
  72. Neurons
    longest cell in the body with three primary parts, 1 perikaryon=cell body containing the nucleus, 2 dendrites=short cytoplasmic extensions that receive nerve impulses, 3 axon=long, single extensions that conducts impulses away from the cell body
  73. Neuroglial cells
    support the neurons
  74. Epithelial Tissue
    • simple squamous
    • simple cuboidal
    • simple columnar
    • stratified squamous
    • stratified cuboidal
    • stratified columnar
    • transitional
    • pseudostratified
  75. Connective Tissue
    • Connective Tissue Proper: loose connective tisse = areolar, adipose and reticular tissue
    • Dense Connective tissue: Dense regular, dense irregular and elastic
    • Specialized Connective Tissue: cartilage = hyaline, elastic and fibrocartilage
    • Bone: compact and cancellous
    • Blood:
    • Muscle tissue: skeletal(striated voluntary), cardiac (striated, involuntary), smooth ( nonstriated, involuntary)
  76. Tissue Healing and Repair
    • Inflammation - the initial response to injuries in which the goal is to limit further damage and eliminate any harmful agents
    • Repair - involves organization of granulation tissue and regeneration of lost tissue or formation of scar tissue
  77. Inflammation
    • nonspecific reaction to injurty or disease
    • steps: 1 vasodilation, 2 swelling, 3 clot formation,4 phagocytosis, 5 capillaries return to normal size, blood flow and fluid leakage into the affected area abate
  78. Formation of Granulation Tissue and Epithelialization
    • tissues that form beneath the overlying flood clot or scabs
    • compsed of a layer of collagen fibers infiltrated with capillaries (that have branched off existing capillaries in deeper layers of damaged tissue)
    • granulation tissue is slowly replaced by fibrous scar tissue
  79. Classifiction of wound healing
    • First Intention: egdes of wound held in close apposition, skin forms a primary union without formation of granulation tissue or significant scarring
    • Second Intention: edges of wound seperated from eachother, granulation tissue forms to close the gap; scarring results
    • Third Intention: contaminated would left open until contamination is reduced and inflammation subsides; later closed by first intention; also called delayed primary closure
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