GI 1: Mouth & Esophagus

• what are the 2 groups of organs in the GI system

  1. alimentary canal
  2. accessory digestive organs
• Alimentary Canal

  • tube that moves through the body
  • mouth, pharynx, esophagus, stomach, small intestine, large intestine
• Accessory Digestive Organs

  • important for the breakdown of food
  • teeth, Tonge, salivary glands, liver, gallbladder, pancreas
• What are the 6 basic properties of the digestive system??

  1. ingestion
  2. secretion
  3. motility
  4. digestion
  5. absorption
  6. defecation
• Tongue

  • pushes food into our teeth so that they can be broken down
• What are the containment parts of the mouth??

  • cheek
  • lips
  • soft palate
  • hard palate
• What are the parts of the mouth used in mechanical digestion??

  • teeth
  • tongue
• What part of the mouth ha tactile and irritant receptors?

  Uvula
• Uvula

  • instigates gag reflexes which is important to protect the respiratory system
• What part of the mouth is used for chemical digestion?

  Opening of ducts

  • submandibular gland
• Openings from ducts/glands

  • enzymes are secreted into the mouth and this is where saliva is secreted from which is needed for chemical digestion
• What are the 4 types of teeth??

  1. incisors
  2. canines
  3. premolars
  4. molars
• how many teeth are there?

  32
• what are the 2 types of dentitions of the teeth??

  1. deciduous (baby teeth)
  2. permanent
• Incisors = cutting

  • front of mouth, for vegetables
• Canines = tearing
• Premolars = crushing
• molars = grinding
• parts of the teeth?

  • enamel
  • dentin
  • gingiva
  • pulp cavity
  • cementum
  • root canal
  • alveolar bone
  • periodontal ligament
  • apical foramen
• Enamel

  • made of calcium salts
  • protects the tooth from wear and tear
  • hardest substance in the body
  • 10-15% more calcium than any other bone
  • cannot be regenerated
• dentin

  • calcified connective tissue
  • makes up the majority of the tooth
  • provides enamel for teeth
• gingiva : gum
• pulp cavity

  • contains pulp (connective tissue containing nerves and blood vessels)
  • "bone marrow of the tooth"
• Cementum

  • a bone-like substance that attaches the root to the periodontal ligament
• root canal

  • an extension of the pull cavity that contained nerves and blood vessels
• periodontal ligament

  • helps anchor the tooth to the underlying bone
• apical foramen

  • opening at the base of a root canal which blood vessels, lymphatic vessels, and nerves enter a tooth
• Nerve of the teeth:

  • CN V (trigeminal)
  • maxillary + mandibular branch
• Mechanical digestion

  • teeth, cheeks, tongue, muscles, saliva
  • saliva mixes in with the bolus to make it more digestible and not as hard
• Intrinsic muscles move the tongue around
• Extrinsic tongue muscles

  1. platogoglossus
  2. styloglossus
  3. hyoglossus
  4. genioglossus
• Extrinsic tongue muscles are innervates by:

  • CN XII: hypoglossal N
  • CN X: vagus N
• Palatoglossus

  • soft palate to tongue
  • move tongue upwards
  • vagus N
• Styloglossus

  • stylus to tongue
  • stylus is the thin bone in front of the auditory meatus
  • moves tongue upwards
  • hypoglossal N
• Hyoglossus

  • hyoid bone to tongue
  • the hyoid bone is the only bone in our body that isn't touching any other bone
  • moves tongue downwards
  • hypoglossal N
• Genioglossus

  • mandible to tongue
  • moves tongue forward
  • hypoglossal N
• Muscles of Mandible to Maxilla Mastication

  • temporalis
  • masseter
  • CN V trigeminal N
• Muscles of Mandible lateral movement mastication

  • temporalis
  • medial pterygoid
  • lateral pterygoid
  • CN V trigeminal N
• Chemical Digestion

  • teeth, tongue, cheeks, muscles, saliva
  • paired (bilateral) glands and ducts
• Glands of chemical digestion

  • parotid gland
  • submandibular gland
  • sublingual gland