Editing PH (section)

=== pH of various body fluids ===
: {| class="wikitable"
|+pH of various body fluids<ref name=Boron2012>{{cite book |last1=Boron |first1=Walter F. |url= https://books.google.com/books?id=54mxMgO5H_YC&dq=pH%20in%20living%20systems&pg=PA652 |title=Medical Physiology: A Cellular And Molecular Approach |last2=Boulpaep |first2=Emile L. |date=13 January 2012 |publisher=[[Elsevier Health Sciences]], Saunders |isbn=9781455711819 |pages=652–671 |oclc=1017876653 |access-date=8 May 2022 |archive-date=8 May 2022 |archive-url=https://web.archive.org/web/20220508051939/https://www.google.co.in/books/edition/_/54mxMgO5H_YC?hl=en&gbpv=1&dq=pH+in+living+systems&pg=PA652 |url-status=live |edition=2nd }}</ref>
|-
! Compartment
! pH
|-
| [[Gastric acid]] || 1.5–3.5<ref>{{cite news|url=https://www.ucsfhealth.org/medical-tests/stomach-acid-test|title=Stomach acid test|publisher=University of California San Francisco|access-date=21 February 2024}}</ref><ref>{{cite book |last1=Marieb |first1=Elaine N. |url=https://books.google.com/books?id=BxDfnQEACAAJ |title=Human anatomy & physiology |last2=Mitchell |first2=Susan J. |date=30 June 2011 |publisher=[[Benjamin Cummings]] |isbn=9780321735287 |location=San Francisco |access-date=8 May 2022 |archive-date=8 May 2022 |archive-url=https://web.archive.org/web/20220508051937/https://www.google.co.in/books/edition/_/BxDfnQEACAAJ?hl=en |url-status=live }}</ref>
|-
| [[Lysosome]]s || 4.5<ref name=Boron2012/>
|-
| [[Human skin]] || 4.7<ref>{{Cite journal|last1=Lambers|first1=H.|last2=Piessens|first2=S.|last3=Bloem|first3=A.|last4=Pronk|first4=H.|last5=Finkel|first5=P.|date=2006-10-01|url=https://onlinelibrary.wiley.com/doi/10.1111/j.1467-2494.2006.00344.x|url-status=live|title=Natural skin surface pH is on average below 5, which is beneficial for its resident flora|journal=International Journal of Cosmetic Science| volume= 28 |issue= 5|pages=359–370|doi=10.1111/j.1467-2494.2006.00344.x|issn=1468-2494|pmid=18489300|s2cid=25191984|access-date=8 May 2022|archive-date=21 March 2022|archive-url= https://web.archive.org/web/20220321033318/https://onlinelibrary.wiley.com/doi/10.1111/j.1467-2494.2006.00344.x}}</ref>
|-
| Granules of [[chromaffin cell]]s || 5.5
|-
| [[Urine]] || 6.0
|-
| [[Breast milk]] || 7.0–7.45<ref>{{cite journal | url=https://pubmed.ncbi.nlm.nih.gov/3748680/#:~:text=Thereafter%2C%20the%20pH%20of%20milk,with%20the%20concentration%20of%20lactose | pmid=3748680 | date=1986 | last1=Morriss Jr | first1=F. H. | last2=Brewer | first2=E. D. | last3=Spedale | first3=S. B. | last4=Riddle | first4=L. | last5=Temple | first5=D. M. | last6=Caprioli | first6=R. M. | last7=West | first7=M. S. | title=Relationship of human milk pH during course of lactation to concentrations of citrate and fatty acids | journal=Pediatrics | volume=78 | issue=3 | pages=458–464 | doi=10.1542/peds.78.3.458 }}</ref>
|-
| [[Cytosol]] || 7.2
|-
| [[Blood]] (natural pH) || 7.34–7.45<ref name=Boron2012/>
|-
| [[Cerebrospinal fluid]] (CSF) || 7.5
|-
| [[Mitochondrial matrix]] || 7.5
|-
| [[Pancreas]] secretions || 8.1
|}

In living organisms, the pH of various [[body fluid]]s, cellular compartments, and organs is tightly regulated to maintain a state of acid–base balance known as [[acid–base homeostasis]]. [[Acidosis]], defined by blood pH below 7.35, is the most common disorder of acid–base homeostasis and occurs when there is an excess of acid in the body. In contrast, [[alkalosis]]  is characterized by excessively high blood pH.

Blood pH is usually slightly alkaline, with a pH of 7.365, referred to as physiological pH in biology and medicine. [[Dental plaque|Plaque]] formation in teeth can create a local acidic environment that results in [[tooth decay]] through demineralization. [[Enzyme]]s and other [[Protein]]s have an optimal pH range for function and can become inactivated or [[Denaturation (biochemistry)|denatured]] outside this range.