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

===== Physiological and Biochemical Maintenance of pH =====
* Fatty Acids from Sebum and Cerumen - Sebaceous glands secrete unsaturated fatty acids (e.g., oleic acid), which lower pH. - Breakdown of cerumen by normal skin flora releases more fatty acids, further maintaining the acidity.
* Regulation by Normal Flora - The microbiota of the external ear contribute to homeostasis by outcompeting pathogenic bacteria and producing acidic metabolic byproducts.
* Epithelial Turnover and Barrier Function - The keratinized epithelium provides a protective layer that prevents alkaline substances (e.g., water or soap residues) from neutralizing the acidic pH.
* Hydration and Ionic Composition - Sweat gland secretions containing Na+, K+, and Cl- ions help maintain a stable environment by influencing ion exchange and water content.
* Immune System Contributions - Secretory immunoglobulins (such as IgA) in cerumen contribute to microbial defense while indirectly influencing pH stability.