mouth, pharynx, and esophagus

tongue

• skeletal muscle in oral cavity

  • aids in mastication 

  • mixes food with saliva

  • Papilla: 

    • contains taste buds

  • Tonsils:

    • Detects pathogens

palate

• roof of mouth

  • hard palate: anterior portion of mouth

    • made of bone

  • soft palate: posterior portion of mouth

    • made of muscle

    • Uvula: helps seal of nasal cavity during swallowing

    • contains tonsils to detect/figt infections

teeth

• hard structures in oral cavity

  • aids in mastication 

  • primary teeth (deciduous)

    • 6 months to 2 years

  • secondary teeth (permanent)

    • start erupting at 6 years

permanent teeth

• 32 total (2 sets of 16)

• Midline to back 

  • central incisor

  • lateral incisor

  • canine (cuspid)

  • 2 premolars

  • 3 molars

tooth anatomy

• Enamel: outer layer of hard calcium salts

• Crown: portion of tooth above gums

• Root: portion of tooth below gums

• Dentin: living cells encased in hard protein

• Pulp: cavity in tooth containing blood vessels and nerves

dental caries (cavity)

• Break down of tooth enamel by bacteria

• Bacteria secrete acids while consuming foods left in teeth

• Acids dissolve calcium salts

muscles in mastication

• Temporalis

• Masseter

• Medial pterygoid

• Lateral pterygoid

bones in mouth

• Maxilla (upper jaw)

• Mandible (lower jaw)

• Palatine (back of upper jaw)

salivary glands

• parotid gland

  • posterior to mouth and pharynx

• sublingual gland

  • inferior to tongue

• submandibular gland

  • inferior and posterior to oral cavity

saliva

• moistens and binds food particles

• dissolves food particles

• chemical digestion of carbohydrates

• cleanse oral cavity

• buffer mouth from big swings in pH

two types of saliva

• Serous fluid

  • water fluid with enzymes

  • salivary amylase: enzyme that breaks down large carbohydrates into smaller sugars

• Mucus

  • thick liquid

  • binds food 

  • acts as lubricant

pharynx

• back of throat

  • contains:

    • nasopharynx

    • oropharynx

    • laryngopharynx

pharynx

• Transfers food from oral cavity to esophagus

• Constrictors muscles initiate swallowing of  food

epiglottis

• cartilage flap

• closes over larynx during swallowing

• prevents food from entering trachea and lungs

swallowing

1. Uvula in soft palate rises and blocks off nasal cavity

2. Epiglottis closes over the trachea

3. Tongue presses against the soft palate and uvula to seal off nasal and oral cavity

4. Constrictor  muscles in pharynx pull down bolus (food)

esophagus

• muscular, collapsible tube

  • ~25cm long

  • passageway for food

  • smooth muscle propels food towards stomach

cardiac sphincter

• lower esophageal sphincter

• Ring of muscle acting like valve

• prevents stomach contents from backing up into esophagus

sphincter

• Ring of smooth muscle

  • Opens and closes

  • Controls flow of materials through a tube