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GIT :apple: - Coggle Diagram

- - - - Mucosal projections
      - Btwn bases of villi
        
        Intestinal glands (simple tubular)
        
        = Crypts of Lieberkuhn
        
        Lined by:
        
        Goblet cells
        
        Paneth cells
        
        Chief cells
        
        Argentaffin cells (occasionally)
  - - - Lubricates
      - Protects ag mechanical irritation
  - - - Myenteric plexus of Auerbach
        
        Btwn circular & longitudinal layers of muscular layer
      - Submucous plexus of Meissner
        
        Submucosa
- - - - Base = basophilic
      - Apex = eosinophilic w/ zymogen granules
    - - IC ducts - have flattened cells that extend into lumen = centroacinar cells
- - - - Supp vascular & bile duct syst's
      - = trabeculae/capsule of Gibbon
      - Surr liver lobules - lobules = structural unit of liver
    - - Interlobular CT
        
        Hard to see except in Pig
        
        P = distinct CT septa
      - Portal canals/tracts
        
        Grp of vessels & ducts w/ supporting CT
      - Lobules
        
        Polygonal prism
        
        Central vein
        
        Intralobular sinusoidal capillaries drain into CV
      - Hepatocytes
        
        Arranged in plates
        
        Granular cytoplasm rich in mito
        
        Polyhedral cells (looks cuboidal) w/ round central nuclei
        
        Smooth & granular ER w/ lots glycogen
      - Sinusoids
        
        Endothelial cells - phagocytic
        
        Stellate macrophages = Kupffer cells
      - Perisinusoidal space
        
        = space of Disse
        
        Btwn endothelium & plates of hepatocytes
  - - - Central V
        
        Sub lobular & Collecting ducts
        
        Hepativ V
        
        Caudal Vena Cava
- - - - = Small epi diverticuli
      - =/ glands
- - - - Muscular layer - skeletal muscle fibres
        
        Mucosa
        
        Ruminants & Horses = Keratinized
        
        Carnivores & Pigs = Non-keratinized
        
        Stratified squamous epithelium
        
        Submucosa
        
        Labial glands - Serous/seromucous salivary glands
  - - - Compound tubuloacinar glands
    - - Skeletal m fibres of buccinator m.
    - - Stratified squamous epi
      - Rums = Macroscopic conical buccal papillae - Prehension & mastication of food
      - Carns & Pigs = Non-keratinized
  - - - Striated muscle, intermuscular CT & fat cells
      - Covered by stratified squamous epi (thickens dorsally)
      - Muscular organ covered by mucosa
    - - Mechanical
        
        Conical
        
        Lrger than filiform papillae
        
        Not highly keratinized
        
        R - torus lingue
        
        Pigs
        
        = tonsilar papillae
        
        Core of lymphatic tiss = lingual tonsil
        
        D, C & P - root of tongue
        
        Lenticular
        
        Flattened, lens-shaped projections on torus lingue of rum tongue
        
        Covered by keratinized stratified squamous epi
        
        Filiform
        
        Thread-like
        
        Keratinized stratified squamous epi w/ thick stratum corneum overlying dermal papilla
        
        Most numerous
      - Gustatory
        
        Fungiform
        
        Scattered among filiform papillae
        
        Non-keratinized stratified squamous epi
        
        Sml dome-shaped (mushrooms)
        
        Contains tastebuds
        
        Sheep & pigs = numerous
        
        Horses & Cattle = sparse
        
        Carnivore & goats = abundant
        
        Vallate
        
        On dorsum of tongue (rostral to root)
        
        Central, dome shaped
        
        Ext slightly above surf
        
        Covered by stratified squamous epi
        
        Vallate papilla
        
        H & P = 1 pair
        
        Carn = 4-6 pairs
        
        R = 8-24 pairs
        
        Serous glands of Von Ebner
        
        Deep to papilla
        
        Prov serous fluid necess for effective tasting
        
        Foliate
        
        Abs in Rum
        
        Lacks taste buds in cats
        
        Rostral to palatoglossal arch
        
        Ducts of serous glands open @ bottom on grooves
        
        || folds of mucosa
        
        Sep by grooves
        
        Taste buds in sides of folds
    - - 4-20 neuro-epi cells btwn supporting cells = taste cells
        
        Distal cuticular process - ends in taste pore
      - Terminations of glossopharyngeal & lingual nn. arranged around taste cells
      - Comp layer of peripheral & some central supporting
      - Can occur in soft palate, epiglottis & free edges of vocal cords
      - Specialized epi cells of SSE of fungiform, vallate & foliate papillae
      - Differ in tasting ability (sweet, bitter, acid, umami, salty)
      - Ellipsoid structures
  - - - Tapering root - fitting into an alveolus of mandibular/maxillary bone
      - Neck - where crown & root meet
      - Crown - projecting above gum
      - Bulk consists of dentine
        
        Covered by enamel in reg of crown
        
        Covered by cement in reg of root
    - - Teeth of equines & cheek teeth of rum's (hypsodont teeth)
      - Cement covers crown & extends into infunibulum
      - Enamel lies beneath cement
    - - Surrounds Pulp Cavity
        
        FIlled w/ soft gelatinous CT
        
        Interlacing collagen
        
        Reticular fibres
        
        Stellate reticular cells
        
        BV's & nerves gain access through root canal
        
        Reduces in size w/ age
      - || branched dentinal tubules & intertubular calcified matrix
        
        Dentinal tubules
        
        Dentinal fibres of Tomes
        
        Processes of tall dentine-forming cells
        
        Odontoblasts
        
        @ periphery of pulp
        
        Forms pre-dentine - becomes calcified = dentine
      - Formed slowly throughout life
    - - Att to root of bony alveolus
    - - Att oral mucous memb to tooth
    - - Ameloblasts
      - Surface - cov by enamel cuticle
        
        = Nasmyth's memb
        
        Formed during eruption
      - || hexagonal prisms
      - Hypsodont teeth - ext to root & infunibulum
      - Brachydont teeth - restricted to crown
    - - Slightly modified bone
      - Formed by cementoblasts
        
        = osteoblasts
        
        Derived from mesenchymal cells of dental sac
        
        Enclosed lacunae - forms cementocytes
    - - Att to cement by Sharpey's fibres = bundles of collagen fibres
- - - - Forms mucosal folds = distention
  - - - Keratinized - H, P & R
      - Non-keratinized - Carn
    - - Longitudinally arr smooth m.
      - Varies in species
- - - - Gastric mucosa
      - Gastric glands
    - - Lined by stratified squamous epi w/out glands
      - Gastric mucosa
    - - Horse = unilocular comp
      - Rum = multilocular comp
      - Dog = unilocular simple
  - - - Gastric glands
        
        In lamina propria - reticular & elastic fibs
        
        Simple or branched tubular
        
        Open into bottom of pits
      - Muscularis mucosa
        
        Smooth m. fibs
        
        Inner = circular
        
        Outer = longitudinal
      - Surf epi
        
        Cont into depressions in gastric mucosa
        
        Gastric pits/foveolae - Incr secretory surf
        
        Simple columnar epi
    - - Special layer = Lamina subglandularis
        
        Inner = cellular layer
        
        Outer = fibrous layer (Stratum compactum)
        
        Btwn bases of gastric glands & Muscularis mucosa
      - Stratum compactum
        
        Densely packed collagen fibres
        
        Offers protection against perfs by bone splinters
    - - Adipose tiss
      - BV's, lymphatics & nerve plexuses
      - Loose CT
    - - Middle circular
      - Outer longitudinal
      - Inner oblique
      - Serosa - present
    - - Proper gastric (fundic) glands
        
        In fundus & corpus
        
        Straight tubular glands - open into foveola/gastric pit via neck
        
        Basal secretory portion
        
        Chief cells
        
        Pyramid-shaped
        
        Prox = pepsinogen granules
        
        Most numerous
        
        Dist = basophilic chromatoid substance
        
        Secrete
        
        Pepsinogen
        
        1 more item...
        
        Rennin - coagulates milk prot's
        
        Parietal cells
        
        Central round nuc
        
        Precursors of HCl
        
        Activates pepsin & renin
        
        Acts as bactericide
        
        Ovoid cells, peripheral to chief cells
        
        Argentaffin cells
        
        Filled w/ granules
        
        Secr serotonin - into caps (not lumen of gland)
        
        Endocrine cells
        
        Throughout gland
        
        Not easily discernable from chief & argentaffin cells w/ H&E stain
        
        Production of GI horms
        
        Secretin
        
        Cholecystokinin
        
        Gastric inhibitory polypeptide
        
        Gastrin
        
        Neck portion
        
        Mucous neck cells
        
        Lined by cuboidal cells (undergoing mitosis)
        
        Deep - columnar cells w/ basally compressed nucleus
      - Pyloric glands
        
        Open into foveola via neck
        
        Secr mucous (mucous secr cells)
        
        Branched & coiled tubular glands
        
        Deeper gastric pits
      - Cardiac glands
        
        Comp tubular glands - high branching & coiling
        
        Cuboidal to columnar epi - secrete mucous
  - - - Reticulum
        
        Folds
        
        Mucosa = stratified squamous epi, lamina propria & muscularis mucosa - forms these
      - Rumen
        
        Papillae
      - Omasum
        
        Laminae
      - Lined by keratinised stratified squamous epi
      - Muscular layer
        
        Inner circular
        
        Outer longitudinal
- - - - Lamina propria = comp glands
      - Cont central collecting sinus - glandular units radiate
      - Lined by simple columnar epi
      - Muscularis mucosae above & below glands
      - Mucosa arr in folds around papillae
        
        Lrg comp glands open into papillae
      - Thin submucosa & muscular layer
    - - Cont gastric pits
      - Muscular layer - fibrous aponeurosis
      - Has keratinoid plate secr by branches tubular glands in lamina propria
      - Lrg submucosa comp to proventriculus
      - V lrg muscular comp to proventriculus
- - - - No villi
      - Crypts of Lieberkühn
        
        Fewer
        
        Longer & straighter
        
        Open into lumen
      - Many goblet cells
      - Lamina propria
        
        Peyer's patches
        
        Lymphocytes
    - - Similar to colon
      - More goblet cells
      - Anorectal line
        
        Transition from rectum to anus
        
        3 zones
        
        Columnar
        
        Longitudinal folds = anal columns
        
        Anal sinuses btwn grooves
        
        Non-keratinized SSE
        
        Intermediate
        
        Non-keratinized SSE
        
        Modif tubuloalveolar glands in submucosa = anal glands
        
        Cutaneous
        
        Keratinized SSE
    - - Anal sacs
        
        Dogs - modified sebaceous glands = circumanal glands
        
        Mucosa of outermost part of cutan zone near jxn w/ the skin
        
        Carns: Ducts from anal sacs open @ jxn of intermed & cutaneous zones
        
        Bilateral evaginations of anal mucosa
- - - - Smooth/Skeletal
      - 2 layers
        
        Inner = circular
        
        Outer = longitudinal
      - Myenteric (Auerbach's) nerve plexus
    - - Lamina propria
      - Muscularis mucosa (Lamina muscularis)
      - Epithelium
      - Mucosal types in GIT
        
        Secretory
        
        Absorptive
        
        Protective
        
        Protective
    - - Serosa = CT w/ mesothelium
      - Adventitia - CT w/o mesothelium
    - - CT +/- glands
      - Meissner's plexus = ganglion nerve plexus of ANS
- - - - Form organs
      - Grown away from oral cavity but remain connected to it by excretory ducts
    - - Sml salivary glands
      - Labial, buccal, palatine & lingual
    - - Modified skin glands
  - - - Has mucus secr tubular end-pieces (acini) characterized by wide lumen from which wide duct leads off
      - Mucus-secreting cells
        
        Compressed basal nucleus
        
        Rest of cell = filled w/ mucigen granules
    - - Separate mucous & serous acini or Both serous & mucous cells
      - Mixed acinus
        
        Elongated
        
        Dist = crescent-shaped collection of serous cells
        
        = crescents of Gianuzzi or demilunes
      - Serous crescents
        
        Intercellular secretory canaliculi
        
        Runs btwn mucous cells
        
        Joins to lumen
    - - Divided into lobules by CT septa
      - Each lobule = aggregation of acini & initial parts of excretory ducts, capps, nerve endings & supporting retinacular CT
      - Acini
        
        Formed by pyramidal shaped cells
        
        Basophilic cytoplasm
      - Pyramidal cells
        
        Secretory granules in apex
        
        Zymogen granules (eosinophilic) = precursors of dig enzymes
      - Myo-epithelial cells
        
        Basket-like contractile shell around secretory cells
        
        Basophilic cyto
      - Intercellular secretory canaliculi
      - Lumen of acinus
        
        Opens into intercalated ducts - lined by low cuboidal epi
      - Intercalated ducts
        
        Joined to intralobular ducts - lined by simple columnar epi
      - Intralobular ducts
        
        Joins interlobular ducts
        
        Prox - lined by columnar epi
        
        Dist = lined by stratified squamous epi