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DIGESTIVE SYSTEM

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DIGESTIVE SYSTEM Powered By Docstoc
					DIGESTIVE SYSTEM



Through stomach
    Overall Digestive Process
 Ingestion
 Movement
 Digestion (mechanical & chemical)
 Absorption (into blood/lymph vessels)
 Elimination = Defecation
           GI Organization
 Digestive tract = canal
 Gastrointestinal tract
 Alimentary canal
 Accessory Structures – outside of the tract
      Microstructure - general
   Mucosa
    – Mucous membrane
    – May have villi and microvilli
   Submucosa
    – Very vascular
 Muscularis
 Serosa = Visceral Peritoneum
             Peritoneum
 Parietal peritoneum
 Visceral peritoneum
 Peritoneal cavity
          Folds of Peritoneum
   Binds organs together, anchors them, suspends
    vessels
   Mesentery proper (SI-Dorsal BW)
   Mesocolon & Mesorectum (LI-Dorsal BW
   Falciform ligament (Li-Ventral BW)
   Lesser omentum (Lesser curvature/duodenum-Li)
   Greater omentum (Greater curvature-Dorsal BS
              Oral Cavity
 Labia
 Labial frenulum
 Hard palate
 Soft palate
    – Uvula
       Tongue (accessory)
 Glosso-
 Lingu-
 Skeletal muscle covered by mucous
  membrane
 Lingual frenulum
                     Tongue
 Papillae
 Taste Zones
    – Sweet, Salt
    – Sour, Bitter
   Function
    – Bolus formation
    Salivary Glands (accessory)
 Parotid
 Submandibular
 Sublingual
                 Saliva
 1-1 ½ liters/day
 99% water
 Mucins
 Amylase
 Lysozyme – anti-microbial
    Saliva Secretion Controls
 Nervous System – Medulla oblongata &
  Pons
 ANS
 Smell, thought, sight, irritation
 Dehydration, Fear
        Teeth (accessory)
 Gingivae
 Crown
 Root
 Neck
        Tooth Components
 Periodontal ligament
 Dentin
 Pulp cavity & pulp
 Apical foramen
 Enamel
 Cementum
                   Teeth
 Deciduous – 20
 Permanent - 32
             Teeth - shape
 Incisor
 Canine
 Premolar
 Molar
       Dental Terminology
 Labial
 Buccal
 Lingual
 Palatal
 Occlusal
    Digestion in Oral Cavity
 Ingestion
 Mastication
 Chemical digestion
 Deglutition
                  Pharynx
   Already did under Respiratory
                    Esophagus
 Hiatus
 Sphincters
 Function
    – Peristalsis
    – Heartburn is actually esophageal “burn”
             Stomach (gastric)
   Anatomy
    – Cardia
    – Fundus
    – Body
    – Pylorus and Pyloric Sphincter
    – Greater Curvature
    – Lesser Curvature
      Digestion in Stomach
 Stores food
 Chyme
 Motility, Mixing & Emptying
 Peristalsis
 To Pyloric Sphincter, to Duodenum
 Pacemaker cells make smooth muscle
  contract about 3x/minute when food present
    Controls of Stomach Motility
 2-6 hours to empty
 Controls include volume & distention
 GASTRIN
    – Hormone released by pyloric cells in response
      to distention. Stimulates gastric motility.
    – Caffeine stimulates gastrin release
    Controls of Stomach Motility
   ENTEROGASTRIC REFLEX
    – As duodenum distends, it inhibits gastric
      motility
 SECRETIN
 CHOLECYSTOKININ
 GASTRIC INIHIBITORY PEPTIDE
            Gastric Secretion
 “Juice”
 Zymogenic Cells make Pepsinogen
 Parietal Cells make HCl
    – Alkaline blood following a meal
   Mucus Cells make protective mucus
Controls of Stomach Secretion
 GASTRIN
 Cephalic, Gastric & Intestinal phase of
  seeing and eating food
 ENTEROGASTRIC REFLEX
 GIP, CHOLECYSTOKININ, SECRETIN
         Stomach Physiology
   Very little absorption

				
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posted:2/27/2013
language:English
pages:57