Lecture: pharynx and esophagus

Pharynx

🔹 Function: Connects nasal & oral cavities to the larynx and esophagus

Passageway for Air: Nose/mouth

→ larynx

Passageway for Food: Mouth

→ esophagus

sections of pharynx

Nasopharynx, oropharynx, laryngopharynx

Nasopharynx

Upper portion, behind nasal cavity, allows air passage.

Oropharynx

Middle section, behind soft palate, allows food & air passage.

Laryngopharynx

Lower section, below oropharynx, directs air to larynx and food to esophagus

Swallowing

A 3-Stage Process

Stage 1

Bolus (chewed food + saliva) is formed and moved to the pharynx by the tongue.

Stage 2:

Swallowing Reflex ✅ Soft palate raises (prevents food from entering nasal cavity). ✅ Hyoid bone & larynx rise, epiglottis covers trachea. ✅ Lower pharynx relaxes, esophagus opens. ✅ Peristalsis in the pharynx moves food into the esophagus.

Stage 3:

Esophageal Movement ✅ Food moves down the esophagus via muscular contractions (peristalsis).

Esophagus Pathway:

Behind trachea, through mediastinum, past diaphragm, into stomach.

Functions of the Esophagus:

✅ Mucous glands – Moisten & lubricate inner lining for smooth passage. ✅ Thick circular fibers – Contract to keep food in the stomach, preventing reflux.