Pharynx - Anatomy & Physiology

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Introduction

The pharynx is part of both the respiratory and digestive system. Both systems have entrances to the pharynx but they are separated from each other by the soft palate.

During exercise or during respiratory distress, the mouth can be used as an additional opening of the respiratory system and then the oropharynx also becomes an air-way.

The pharynx can be split into different regions- the oropharynx, oesophageal/laryngeal pharynx and the nasal pharynx

Structure

• Opening of the larynx is on the floor of the pharynx

• Caudal and dorsal to the laryngeal opening is the opening into the oesophagus

• In the dorsal region of the nasal pharynx there are paired openings into the Auditory (Eustacian) Tubes

• The lining of the middle ear cavity and auditory tube is continuous with that of the nasal pharynx

• Walls are muscular

• Located between the base of the skull and the first two cervical vertebrae dorsally

• larynx ventrally

• Mandible, pterygoid muscles and hyoid apparatus laterally

• During swallowing the soft palate is raised which divided the pharynx into dorsal and ventral sections
  • Laterally, two pairs of palatopharyngeal arches are present from the soft palate to the oesophagus
  • The dorsal compartment is the nasal pharynx
  • The rostral compartment is the oropharynx

• The laryngeal pharynx is separated from the oropharynx by the epiglottis

• Tonsils are present on the lateral walls of the oropharynx
  • Covered by flaps of mucosa
  • Partially visible in the open mouth

Species Differences

Canine

• Single duct connects nasal pharynx to the nasal cavity

• Tonsils are a compact mass which point away from the lumen of the pharynx

Equine

• Auditory tube opens into the gutteral pouch

• Tonsils are diffuse and raised slightly

Ruminants

• Tonsils are a compact mass which point towards the lumen of the pharynx

Links

Oropharynx - Anatomy & Physiology

Nasopharynx - Anatomy & Physiology

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