VPB 121: Veterinary Physiology - II (2+1)

MASTICATION REFLEX

• Reflex activity under the control of brain stem.
• Mastication is basically voluntary but usually takes place involuntarily.
• Mastication reflex or chewing reflex is by the rhythmic movement of the mandible.
• Lowering of the mandible due to the extension of the tongue is known as linguo mandibular reflex.
• Stimuli for masticatory reflex is the presence of food in the oral cavity
• Receptors in the tongue and oral mucosa initiate mastication by the sense of food.
• Sensory impulses are carried via trigeminal, facial and glossopharyngeal nerves to brain stem.
• Motor orders reach masticatory muscles via trigeminal nerve
• This inturn causes rhythmic movement of mandible in relation to the maxilla.
• This results in shearing and crushing a food.
• The main masticatory muscles supplied by trigeminal nerve include Temporalis with assistants from Massetor muscle for shearing and Massetor with assistants from Pterygoid muscles for grinding.