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Histology Pt. 4 - Coggle Diagram

- - - - Basal Cell, Prickle Cell, Intermediate and Superfical cell layers
    - - Orthokeratin
        
        Basal Cell, Prickle Cell, Granular intermediate and keratinized cell layers
      - Parakeratin
        
        Basal Cell, Prickle Cell, Intermediate and modifed superfical cell layers
  - - - Basal Cell
        
        Where mitosis occurs
      - Pickle cell/spinous cell
        
        Prickel apperaance due to widening of the space between intercellular desmosomes on histo processing
        
        Area os division of basal cells
      - Intermediate Cell Layer
        
        larger, fewer cells
        
        Glycogen or granules may be seen
      - Superficial Cells
        
        non-keratinising epithelium = falter and contain nuclei
        
        Kertansed epithelium = keratinised cells
        
        pyknotic nuclei in parakeratin membranes
    - - Non-Kertinaocytes
        
        Merkles Cells
        
        Neural crest derived = sesnory cells = found in masticatory mucosa
        
        Melanocytes
        
        Neural cres cell derived, produce melanin
        
        Skin colour is arefelction of melanin production not melanocyte numbera
        
        Dendritic (Langerhan) Cells
        
        Antigen Presenting cells
    - - Masticatory Mucosa
        
        prominent epithleial rete ridges and long CT papillae since its subject to more mechanical abrasion and stress
      - Lining Mucosa
        
        nb: Lining mucosa has shallower rete ridges, broad and short ct papillae cause it is not sbject to stress
    - - Epithelial-Connetive Tissue Junction
        
        Lamina lucida
        
        Connects the epithelium via Hemidesmosomes
        
        Immediately beneath the epithelium, a gyloprotein layer = comprises of laminin, intergrins, fibronectin
        
        Lamina Densa
        
        Beneath the lamina lucida, compromises of Type IV collagen and proteogylcans
        
        Anchoring fibrils insert here to provide mechanical adhesion for oral epithelium and lamina propria
      - Lamina Propria
        
        Paillarly Layer
        
        Nearest the epithelial rete pegs = connective tissue papillae
        
        loosley arranged colagen fibers in ground substance
        
        Reticular layer
        
        Contains type I collagen fibers, elastin, as well as blood vessles, nerves, ground substance and may other cell types
        
        Ofte called the submucosa
        
        Cells in Lamina Propria
        
        Fibroblasts
        
        synthesise collagen, elastin and groun substance
        
        Can be active or resting
        
        MØ
        
        Phagyocytic immune cells
        
        Nb: They are the reason for tatoos lasting so long as the ink can pass from on MØ to another
        
        Mast Cells
        
        granulocytes (histamine and heparin)
        
        Lymphocytes
        
        profuse in lymphoid tissue, not often in lamina propria
      - Fibers of Lamina propria
        
        90% Type I collagen, 8% type III and the rest IV and VIII (elastin!!)
        
        ground substance
        
        GAG, proteoglycans, glycoproteins
    - - Derived from V, VII, IX and X
      - Papillary layer of the CT
        
        Merkles receptors(pressure)
        
        Meissner's corpuscle (touch)
        
        Ruffini's Corpuscle (touch, pressure and stretch)
        
        Pacinin's Corpuscle (vibriation)
        
        Free nerve endings (pain)
  - - - (Skin) = hair folliucles, sebasceous gland and sweat glands
      - Orthokeratin epithelium
    - - Vermillion Zone = Red surface
      - Parakeratin epithelium
        
        Subject to a lot of wear and tear
    - - labial mucosa
      - non-keratinised squamous epithelium
      - Contains: minor salivary glands, large rete pegs
  - - - Intrinsic Muscles
        
        Horizontal, Vertical and Transverse fibers
      - Extrinisc Muscles
        
        Hyoglossus, genioglossus, palatoglossus, styloglossus
    - - [SVS]Taste: Anterior 2/3 (VII), Posterio 1/3 (IX), Epiglottis (X)
      - Motor: Intrinisc/extrinisic (XII), Exept palatoglossus (X)
      - [GSS]: Anterior 2/3 (VII), Posterio 1/3 (IX), Epiglottis (X)
    - - Filiform papillae
        
        Keratinized epithelium, numerous, in parallel roles across the tongue
        
        Nerve endings for touch
      - Fungiform papillae
        
        Thin, non ketainized epithelium
        
        consists of taste buds
      - Foliate paillae
        
        found on the lateral aspect of the tongue
        
        also taste fibers
        
        Sweet, bitter, salty, sour and Umami
      - Valate papillae
        
        aka cicumvallate papillae (~7-12 in each person)
        
        cotribute to taste
        
        Keratinized epithelum covering with core of lamina propria
    - - non-keratinised, squamous epithelium of lymphoid tissue
  - - - nb: lamina propria is continuous with the periostium of the hard palate for rigid fixation to it
      - Statified squamous kertaized epithelium
        
        guard against abrasion and injury
    - - Superior Surface
        
        pseudo-statified ciliated columar respiratory epithelium
        
        Forms the posterio part of the nasal cavity
      - Inferior surface
        
        Statified squamous non-kertaized epithelium
        
        lamina propria and muscle (tensor veli, and levator veli, MuV)
  - - - Either Ortho or Para-kertainized
- - - - Organic (tensile stregth)
        
        Collagen (Type I) (33% total weight)
        
        GAGs, proteins and proteoglycans
        
        Cells
        
        Osteoprogeintor cells
        
        Produces osteoblasts
        
        mesenchymal stem cells
        
        Maintain population of osetoblasts
        
        improtant dueing bone fractures
        
        Found in the periosteum
        
        Oesteoblasts
        
        build bone
        
        Secrete collagen and ground substance & mineralise the bone
        
        Inital bone structure = osteoid (unmineralized)
        
        screte vesicles into the osteoid to evelavte calcium and phostpahe conc in the bone to minersalise the bone
        
        Osteocytes
        
        maintains the bone
        
        Trapped in bone during formation
        
        found lacunae
        
        In layers called lamellae
        
        Connect to one another via lamellae
        
        Not terminally differnetiated, so iuf release will form osetoblasts
        
        Osteoclasts
        
        breaks down bone
        
        derived from monocytes
        
        produce aids and protecolyic enzymes
        
        regulates Ca++ in the blood
      - Inorganic (compressive strength)
        
        hydroxyapeitie (85%)
        
        Calcium carbonate (10%) (66% ot total weight)
    - - Osteon (Haversian System)
        
        a central canal (haversian canal) is surrounded byconcentric layers os osteocytes
        
        run parallel to the bone surface
      - Volkmann Canals
        
        penetrating canals run perpendicular to bone and carry blood vessl to supply the marrow
      - Intersitial lamella - inbetween the osteons
      - Canailiculi
        
        connect lacuane to each other the haversion canal and allow for nutrient and wster removal
      - Periosteum
        
        Isolates the bone from surrounding structures.
        
        Provides circulatory and nervous supply to bone
        
        An abundance os osteoprogenitor stem cells
        
        nb: at the TMJ the peiosteum becomes the joint capsule and disc in the TMJ
      - Endosteum
        
        Incompleet cellular layer that lines the yellow-marrow cavity
        
        Covers the matic of trabeculae and comprosed of stem cells and is active during growth and reapir
    - - Cancellous
        
        Trabeculae = cross-branching network
        
        Provide resistance against stress
        
        Red-bone marow is found inbetween the osteocyte network
        
        marrow supplies nutients and removes waste
      - Compact bone
        
        typically oseton structure
    - - Vitamin C
        
        proline hydroxylation for Collagen
        
        Deficiencies can lead to scurvy
      - Vitamin D
        
        promotes calcium/phosphate absoption from the gut/kidneys
        
        Deficiences = rickets or osteoporosis
      - Blood supply
        
        1) Periostium
        
        2) Musculature Vessles
        
        3) Main vessels (intra canals)
        
        ie Inferior alveolar artery in the IAN canal
        
        4) Nutrient vessels
        
        penetrate the bone from other vessels
  - - - Calvaria (flat bones)
        
        Layered: Compact - Cancellous - Compact
        
        Ex. Frontal, parietal, zygomatic, partos of the occipta/temporal bones and the mandible and maxilla
      - 1) An ossification center appears in a (mesechymal) fibrous connective tissue where osteoblasts have differentiated
      - 2) Bone matix (osteoid) is secrted and mineralised, trapped osteoblasts become osteocytes
      - 3) Accumulating osteid forms between blood vessles form trabecular woen bone and the periosteum forms
      - 4) Bone collar forms at the periphery to form the compact bone, and vessels within the trabecular becomes red marrow
    - - Pre-existing hyaline cartilage model and the bone repalces it
        
        Bone Growth
        
        Intersitial Growth
        
        Increase in length
        
        Occurs from the epiphyseal plate
        
        chrondrocytes divide to produce a hyaline matrix which is then calcified and replaced by bone
        
        Apopistiional Growth
        
        Increase in width
        
        circumferential lamellae are produced (osteoblasts) and the inner layer is resobed (osteoclasts)
      - Examples: Skull base, vertebrae, bone extremities
      - 1) Bone collar forms around the shaft of the cartilage
        
        perichondrium is infiltrated w/ blood vessels, stimulating mesechymal cells to diff. to osteoblasts
        
        Begins in the diaphysis at the primary ossification centre
      - 2) Cartilage in the centre of the shaft ossifys
        
        Chondrocytes are rapidly replaced by the calcificed matrix, and the bone begins to elongate
      - 3) A periosteal bud invades intetrnal cavities and cancellous bone forms (nutrient vein and artery)
      - 4) medullary cavity forms
        
        as primary ossification enlarges = continues to elongate
      - 5) Epiphyses ossify
        
        Epiphyses calcify and bone growth stops
        
        Epiphyseal plates are the seconday site for ossification
        
        There is no medullary cavity in this area
        
        Articular cartilage remains
  - - - Outer: Cortical Bone
        
        lamellar/compact bone supported by haversian system
        
        The amount of cortical to bundle varies in requirements to force
        
        canines require high force resistance, therfore less budle bone
      - Inner: Bundle Bone (lines the socket)
        
        Cribriform plate = volkmanns canals allows for vessel and nervous penetration to reach the PDL
        
        What the collagen fibers of the PDL are embedded into
        
        Trabecular/spongy bone
    - - lamina dura
        
        bundle bone of incraesed radioopacity of of the thick bone that lines the socket and the sharpeys fibers
- - - - P/SNS from inferior salivatory nucleus carried by CNIX (via otic ganglion)
      - SNS from SCG along the ECA to the gland
      - Serous Saliva (watery)
    - - P/SNS from superior salivatory nucleus carried by CNVII (via submand ganglion)
      - SNS from SCG along the facial artery to the gland
      - Mixed Gland
        
        serous-mucous type
    - - P/SNS from superior salivatory nucleus carried by CNVII (via submand ganglion)
      - SNS from SCG along the facial artery to the gland
      - Mixed gland
        
        predominately mucous
  - - - Serous = watery
        
        Looks histologically like a pie
        
        nucleus is close to the bas eof cell to allow for cytoplasm to contain all the manufacturing components for protein production
      - Mucous = viscous
        
        Larger, flatter appearance
        
        Less basophillic, lots of globules of mucous
        
        Serous demilunes (half-moons) seen in mixed glands and stain well
    - - Exretory Duct (Interlobular)
        
        sepearated by fibrous ct. septum
        
        initally pseudostratified columnar epithelium --> stratifed epithelum
        
        Connect to the oral cavity
      - Striated Duct (intalobular)
        
        Runs from the acnii = thinner and smaller
        
        Drains into the exretory ducts
        
        Eosinophillic appearance
        
        Striated columnar cell
        
        folded membrane at the lumen for secetion
      - Myoepithelial cells
        
        Smooth mucles cells that squeeze the acinus and intercalated ducts
      - Acinii
        
        Secertory unit
      - Intercalated ducts
        
        inbetween the different acinni = drains into the striated ducts
        
        Cuboidal Cells
    - - Modification of saliva
        
        Acinii
        
        Isotoinic = secereted NaCl and water
        
        Striated duct
        
        Hypotonic = absorbed NaCl, secreted HCO3-K+
    - - P/SNS releases ACh to activate muscarinic recerptors to increase blood flow and amd HCO3- and Ca++ seceretion by duct cellls and contraction of myoepithelial cells
      - SNS decreses blood supply and reduces saliva production and increases the amount of protein in the saliva
- - - - Separated by the articular disc into two-compartments (upper and lower space)
    - - This is mesiated by the muscles of mastication and accessory muscles
        
        MOM = Temporalis, masseter, medial and lateral pterygoid
        
        Acces. = Posterior belly digastric + mylohyoid
  - - - Foot-ball shaped process
        
        Articluate with the disc
      - This articulates with the inferior surface of the zygomatic process of the temporal bone
        
        aka. Glenoid or mandibular fossa
        
        Nb: Articular tubercle is a bony prominenc of the zygomatic process and the TMJ does not move over this area
    - - Compact, DFCT disc --> lies between the eminence of the temporal bone and the condyle
      - "meniscus" = avascular, acellualr disc + ground substance
      - Subject to wear = needs to regenerate
        
        Has a regenrative zone = which contains mesenchymal cells which can differnetiate to replace the articular disc
    - - covered in fibrocartilage bathed in synovial fluid
    - - 1st Branchial Arch muscles (V3)
        
        specialsed sketetal muscle
        
        thin actin and thick myosin filamanets = link in crossbridging
        
        plasma membrane = sacrolemma and the cytoplasam = sarcoplasm and the ER is the = sacroplasmic reticulum
        
        Myofibrils = contractile unit
        
        sacromere = featutes of the striation (Z-lines)
        
        Myofilaments = thick (myosin) and thin (actin) filaments
        
        A myosin is surrounded my x6 actin filamanets which during contraction walk along the myosin and shorten the sacromere (Z-lines come closer together)
        
        Muscle contractions
        
        motor nerurons cause depolarisation of the sarcolemma via ACh, this propgates along the tu-tubles causing Ca++ to be release from the sacroplasmic reticulum which initaes a muscle contraction
        
        Contains many mitochondia to pwer them
        
        Long cells with many nuclei
      - Ex. Temporalis
        
        Moves the mandible upwards and backwards
        
        Originates from the Tempral fossa and fascia --> Intermediated tendon and inserts on the coronoid process of the mandible and anterior surface of the ramus
      - Ex. Lateral Pterygoid
        
        Originates from the infratemporal surface/lateral aspect of lateral pterygoid plate and attaches to the mandibualr fovea on the anterior aspect of the mandible neck and the TMJ capsule and disc
    - - Joint Capsule
        
        Dense fibrous Connect Tissue (DFCT)
        
        lined w/ synovial fluid (innervated by SNS)
        
        Fibroblasts for maintenance of collagen
        
        Contains somatic sensory and proprioception fibers (Auriculotemporal and Massteric V3)
      - Lateral Ligament
      - Accessory
        
        Sphenomandibular
        
        Attaches to the lingula (derived from meckle's cartilage
        
        Incorporated into the superficial layer of the deep cerical fascia (or Investing Fascia)
        
        Stylomandibular
- - - - Cementum and Bone
    - - Gingiva
        
        Basic principals
        
        Oral mucosa that is bone to the tooth and bone
        
        Gingiva is keratinised and under goes constant renewal
        
        Appearance
        
        Stippled = represents fibrous attachements of of underlying bone
        
        Colur: dependnant on melanin pigments and degree of keratinization
        
        Functions
        
        Protection
        
        For supporting structures of tooth
        
        Attachement
        
        junctional epithelium to the tooth
        
        Architecture
        
        Oral Epithelium
        
        Attatched gingiva
        
        keratinizsed due to abrasion during mastcation
        
        delinated by the mucogingival junction
        
        Free Gingiva
        
        Collar of the tooth
        
        delinated by teh free gingival groove
        
        Keratinzised squamous epithelium (high turnover) due to trauma
        
        Interdental papilla/col
        
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        Histological Features
        
        Basal layer is cuboidal/columnar & superficial is keratinised
        
        Spinous layer (prickle cell)
        
        Adajcent cells are attached by desmosomes
        
        Sulcular epithelium
        
        Gingival Sulcus
        
        Allows PMN and abs to flow through and sceretes crevicualr fluid
        
        Lines the gingival sulcus
        
        Non-keratinised tissue
        
        Histological Features
        
        thin stratifed squamous epitheilium, non-keratinsed
        
        Alveolar mucosa
        
        non kertainized
        
        appears a dark red in caucasoid due to blood vessles showing through
        
        Junctional Epithelium
        
        Attactehes to the acellular afibular cementum at CEJ and then the AEFC along the normal root cementum
        
        Histological Features
        
        Stratified squamous cells, non-keratinising
        
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        ONLY TWO LAYERS
        
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        Developes from the Reduced Enamel Epithelium (REE) as the tooth erupts, which is later replaced by the gingival epithelium
        
        Cellular attachments via demsosomes
        
        Connective Tissue Corium
        
        Lamina propria
        
        Type 1 & 3 collagen fiber network
        
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        Dentiogingival Fibers
        
        Functional unit of the dentinogingival fibers and junctional epithelium
        
        Dentogingival Group
        
        Cementum --> to lamina propria above alvolar crest
        
        Dento-periosteal Group
        
        Cemetum --> perioseum of the buccal/lingual bone
        
        Alveolar-gingival Group
        
        fibers radiate from the alveolar crest into the lamina propria of the free/attached
        
        Examples
        
        Cicular Fibers
        
        Trans-septal fibers
        
        Trans-gingival fibers
        
        Semi-circular fibers
        
        Interdental fibers
        
        Vertical fibers
        
        Longitudinal fibers
        
        Blood Supply
        
        vessels from the PDL, alvolar process and supraperiosteal vessles
      - PDL
        
        Functions
        
        Physical
        
        attachment, and shock absorbtion
        
        Formative
        
        Repair/Resoprtion of cementum and bone
        
        Nutrition
        
        supplies nutrients to bone, cementum and gingiva
        
        Sensory
        
        Proprioception druring fucntion and jaw relfexes
        
        Eruption
        
        key pre-post eruptive phases
        
        Homeostasis
        
        remodelling based on function
        
        Structure
        
        Fomation begins after tooth formation begins
        
        Collagen fibers (type 1 & 3) which cross the PDL space are the principal fibers
        
        terminal protion sof the principal fibers in th bone and cementum are called Sharpey's fibers
        
        There is no elastin in the prinipal fibers at they are not meant to be stretchy
        
        There is an instersitial space for blood vessels and lymphatics
        
        Fibers change in direction during eruption
        
        Gomphosis
        
        fibrous join of the tooth socket
        
        Oxytalan fibers
        
        Support vessels which run longitudinally and prevent occlusion of blodd vessels when we clench!
        
        Elastic fibers
        
        Fiber Groups
        
        Alveolar crest
        
        transmit occlusal forces
        
        Horizontal Group
        
        resist proximal tooth movement
        
        Oblique Group
        
        transmit occlusal forces to bone
        
        Apical Group
        
        Cushion the occlusal forces
        
        Interradicular group
        
        in multi-rooted teeth
        
        Transmit occlusal forces
        
        Cell Types
        
        Fibroblasts
        
        65% of the cells
        
        Formation and mainatence of collagen fibers
        
        WBCs
        
        Mo, Mast cells, Lymphocytes
        
        Osteocytes on the bone surfaces and cementocytes on the cemtnum surface
        
        Epithelial rest cells of Malassez (HERS distintergration)
        
        Ground Substance
        
        = viscous to support function
        
        glycoprotiens, fibronectin, osteonectin, lamin, and chondronectin
        
        Proteoglycans
        
        act as a seive for small molecules
        
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