Regarding the endolymphatic sac, which of the following best describes its primary immunological function?
- A It is a site of antigen processing and immune surveillance for the inner ear ✓
- B It is the primary site of endolymph production via active Na+/K+ ATPase transport
- C It produces secretory IgA for the scala media
- D It filters perilymph entering through the cochlear aqueduct
Correct answer: A. It is a site of antigen processing and immune surveillance for the inner ear
Explanation
The endolymphatic sac, located in the posterior fossa between the two layers of dura mater, functions as the primary immune organ of the inner ear. It contains macrophages, mast cells, and lymphocytes and serves as the site of antigen processing and immune surveillance. Obstruction or dysregulation of sac function leads to endolymphatic hydrops, which is the pathological basis of Meniere's disease. Endolymph production occurs primarily in the stria vascularis of the cochlea, not in the endolymphatic sac.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.