Editing Openai/67e79947-d378-8007-ae40-5d817d80ade5 (section)

===== Factors Determining the Acidic pH of the External Ear Canal =====
# Sebaceous and Ceruminous Gland Secretions - The external ear canal contains sebaceous glands (which produce sebum) and ceruminous glands (which produce earwax or cerumen). - Cerumen is slightly acidic due to the presence of long-chain fatty acids (e.g., oleic acid and palmitic acid) and lactic acid. - Sebum also contains free fatty acids, which contribute to the acidity.
# Microbial Metabolism - The commensal (normal) microbiota of the external ear canal, such as Staphylococcus epidermidis, produce acidic byproducts, further reducing pH. - This acidic environment inhibits the growth of pathogenic bacteria and fungi like Pseudomonas aeruginosa and Candida albicans.
# Sweat Glands and Their Secretions - Sweat contains lactic acid and urea, both of which contribute to maintaining a slightly acidic environment. - The sodium-potassium balance in sweat also influences local pH.
# Desquamation of Epidermal Cells - The external ear canal undergoes continuous shedding of keratinized epithelial cells. - The breakdown of these cells releases weak organic acids, further supporting an acidic pH.
# Buffering by Amino Acids and Proteins - Some proteins and peptides in cerumen act as buffers, helping to stabilize pH. - These include lysozyme, which is both antimicrobial and contributes to pH maintenance.