What is the normal pH of Blood?

The pH of blood is an indication of acidity or alkalinity in the body. It is an important indicator of good health. The normal pH is essential for the optimal activity of the body so it is balanced by different physiological processes.

The normal pH of a healthy person ranges from 7.35 to 7.45. It is slightly basic.

Blood pH Regulation

Our body maintains the normal pH by acid-base balance. It is important to maintain homeostasis.

There are various factors that regulate blood pH. The pH of blood plasma depends on CO2, electrolyte and weak acid concentrations. The two main organs that regulate blood pH are:

  • Lungs- They are in the gaseous exchange and remove CO2. The brain regulates breathing process so the brain and the lungs maintain blood pH by regulating the speed and intensity of breathing.
  • Kidney- They maintain pH balance through excretion. They remove the excess acid or bases present in the blood.

So, our body maintains pH balance through respiration, excretion and other metabolic activities. Any change in blood pH, i.e acidosis or alkalosis is due to impaired function of these organs.

Causes of Abnormal blood pH

Too high or too low pH is an indication of some organ dysfunction. Acidosis or alkalosis is mostly due to impaired functioning of lungs or kidneys. Any change in the blood pH may be due to various diseases such as diabetes, poisoning, infection, heart, lung or kidney diseases.

High Blood pH

High blood pH or alkalosis occurs when the pH of blood is higher than the normal. It may be caused due to temporary illness or some serious condition.

High blood pH may be due to the following reasons:

  • Excessive loss of fluid such as excessive urination, vomiting, diarrhoea, etc.
  • When kidneys do not remove excessive alkaline substances from the blood.

Low Blood pH

There are various causes for acidosis and it is more prevalent than alkalosis. The main reasons for acidosis include:

  • Ketoacidosis in diabetes.
  • Metabolic acidosis due to kidney diseases or failure.
  • Respiratory acidosis due to lungs diseases such as pneumonia, bronchitis, asthma, chronic pulmonary diseases.

So, it is important to maintain the normal blood pH. High pH or low pH is not a disease in itself but are due to certain disorders. It is a key determinant in the initial diagnosis of diseases.

This was a brief note on pH of Blood. Explore notes on Blood composition and other important concepts related to NEET, only at BYJU’S.

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