Pharynx

The pharynx is a musculo membranous tubular structure that is not aided by the support of any bony or cartilaginous matrix. It has distinct functions during breathing, deglutition, and vocalisation. In mammals, the pharynx is located where the digestive and respiratory tract combine. It is generally called the “throat”. The human pharynx is bent at a sharper curve than the pharynx of other mammals. This enables humans to generate a wider variety of sounds but also puts them at threat of choking.

Location of the Pharynx 

The pharynx is located just behind the nasal cavity and ends almost above our oesophagus and larynx. The oesophagus and larynx are the two major passageways that obey passage at the mouth for food and air, respectively. 

• The pharynx is the mutual space of the respiratory and digestive zones.
• It is located at the back of the nasal and oral compartments.
• It proceeds below into the divided larynx and oesophagus.

Structure of the Pharynx 

The structure of the pharynx is somewhat funnel-shaped.

• It is roughly 12 cm in length, extending from the base of the skull down to the lower boundary of the cricoid cartilage.
• The pharyngeal wall is nearly totally posterior and lateral to its cavity.

Anatomy of the Pharynx

The anatomy of the pharynx includes:

• Nasopharynx: It is located at the top portion of the throat in between the base of the skull and the soft palate. It links the nasal cavities and allows air to pass through.
• Oropharynx: It is located in the middle part of the throat in between the soft palate and the superior boundary of the epiglottis. It enables air, food and fluid to pass through.
• Laryngopharynx: It is located at the lowermost part of the throat in between the superior boundary of the epiglottis and the inferior boundary of the cricoid cartilage at the sixth cervical vertebra (C6). It governs the entry of air to the lungs and food and fluid to the oesophagus.

The pharynx also contains three sets of tonsils which are located at the back of the throat and the floor of the tongue. They are regarded as the body’s first defence against infection. 

Eustachian tubes are also a part of the pharynx which attach the ears to the throat. They equalise pressure and help in draining fluid.

The Function of the Pharynx 

Because of its setting,

• The pharynx aids the respiratory system by enabling air to make its route to the respiratory tract. 
• For digestion, the muscles enclosing the pharynx function jointly to send food and drink to the oesophagus.
• The circular muscles push food towards the intestines, while the longer muscles work towards widening and lifting the pharynx, making it likely to swallow.
• The pharynx also plays an important function in speech. It is an enclosed space that can change the structure so that air is able to pass through the pharynx to the voice box. Thus, the pharynx is able to amplify that sound.

Pharynx in Flatworms 

The flatworm has a bilateral body with a head, a brain and stereo eyes that allow it to vigorously hunt. The pharynx in flatworms is located in the centre of its underside. It has no circulatory system, and it’s the gut that allows food to all components of the body.

Flatworms have a simple pharynx that can only take in tiny organisms. With the help of the pharynx, the flatworms swallow small target animals wholly or suck in the body fluids of larger animals. The ingested food winds up in the animal’s gastrovascular cavity. Hence, the pharynx serves as the entry and exit point of the digestive system.

Conclusion 

The pharynx is a cone-shaped muscular canal that binds the nasal and oral cavities to the oesophagus and larynx. Starting from the base of the skull, it terminates at the secondary boundary of the cricoid cartilage at the sixth cervical vertebra. 

The pharynx serves as both the respiratory and digestive processes, whose chamber is lined completely by mucosa. Pharyngitis is a disease of the pharynx or tonsils which accounts for more than 12 million healthcare events yearly in the United States. It is generally induced by a viral infection.