Fish & Invertebrate Oral Health

Question 1

What is the oral cavity lined with?

What species have pharyngeal jaws? What about pharyngeal teeth?

What are the various tooth types in fish?

Describe the esophagus of teleost fish?

Answer 1

Oral/Pharyngeal Cavity

• Lining of oral cavity - thick epithelium and dermis bound to bone or muscle
• Some have ornate, protruding maxillary rostrums or telescopic mouth
• Some have pharyngeal jaws (moray eels)
• Fish tongues - limited mobility, simply propel food into esophagus
  
  • Some have teeth on tongue to hold prey
• Buccal glands - produce mucus; no salivary glands
• Thyroid hyperplasia (goiter) - typically presents as mass along gill arches in bony fish
• Dentition varies - acrodont teeth w/ ankyloses (fibrous attachment) to jaw
  
  • Tooth types - canine, molariform, incisor, plate-like (lungfish, gar)
    
    • Hinged pointed backwards (pike); front teeth grow continuously in parrotfish, pufferfish and may require trimming
    • Some lack teeth - filter feeders, seahorses, pipefish, sturgeon
    • Pharyngeal teeth - holding, masticating, grinding food (if present, often lack muscular stomach)
• Esophagus - short, muscular tube; straight in most spp. but know differences/angularity when gavaging
  
  • Angle into stomach can be dramatic (lookdowns), misplaced tube can perforate
  • In some spp., has blind diverticular lined w/ calcified esophageal teeth
  • Folds present in sturgeon; epithelium may have abundant mucus, esp. in carnivores