pH in the Human Body
The pH of the human body lies in a tight range between 7.35-7.45, and any minor alterations from this
range can have severe implication
pH different of body fluids
Although the pH of blood ranges from 7.35-7.45, the pH of other body fluids is different. pH
indicates the level of H+ ions, where low pH indicates too many H+ ions and high pH indicates
too many OH- ions. If the pH levels drop below 6.9, it can lead to coma. However, different
body fluids have different pH values. The pH of saliva is ranges from 6.5 to 7.5. After
swallowing, the food reaches the stomach where upper and lower parts of stomach have different
pH values. The upper part has a pH of 4−6.5, while the lower part is highly acidic with a pH of
1.5−4.0. It then enters the intestine which is slightly alkaline, with a pH of 7−8.5. Maintaining
the pH values of different regions is critical for their function.
Impact of altering the pH balance
Different organs function at their optimal level of pH. For example, the enzyme pepsin requires
low pH to act and break down food, while the enzymes in intestine require high pH or alkaline
environment to function. Similarly, any increase or decrease in the blood pH can lead to several
disorders.
Maintaining the body pH
pH is maintained in the body using primarily three mechanisms: buffer systems, respiratory
control, and renal control.
Body system
Proteins form a part of the buffer system to regulate the pH levels. These proteins can act as H+
acceptors or donors because of the presence of basic or acidic groups. Similarly phosphate buffers also
help in moderating the levels of pH. Buffers may help in regulating pH during minor physiological
changes, such as during breath holding (which increases the CO2 in the blood), exercise (which increases
lactic acid in the blood), or when gastric acid is secreted.
Respiratory control
The pH of blood during normal conditions is 7.4. However, CO2 dissociates into carbonic acid in
the tissues. Thus, presence of more CO2 makes the blood more acidic. That is the reason when
The pH of the human body lies in a tight range between 7.35-7.45, and any minor alterations from this
range can have severe implication
pH different of body fluids
Although the pH of blood ranges from 7.35-7.45, the pH of other body fluids is different. pH
indicates the level of H+ ions, where low pH indicates too many H+ ions and high pH indicates
too many OH- ions. If the pH levels drop below 6.9, it can lead to coma. However, different
body fluids have different pH values. The pH of saliva is ranges from 6.5 to 7.5. After
swallowing, the food reaches the stomach where upper and lower parts of stomach have different
pH values. The upper part has a pH of 4−6.5, while the lower part is highly acidic with a pH of
1.5−4.0. It then enters the intestine which is slightly alkaline, with a pH of 7−8.5. Maintaining
the pH values of different regions is critical for their function.
Impact of altering the pH balance
Different organs function at their optimal level of pH. For example, the enzyme pepsin requires
low pH to act and break down food, while the enzymes in intestine require high pH or alkaline
environment to function. Similarly, any increase or decrease in the blood pH can lead to several
disorders.
Maintaining the body pH
pH is maintained in the body using primarily three mechanisms: buffer systems, respiratory
control, and renal control.
Body system
Proteins form a part of the buffer system to regulate the pH levels. These proteins can act as H+
acceptors or donors because of the presence of basic or acidic groups. Similarly phosphate buffers also
help in moderating the levels of pH. Buffers may help in regulating pH during minor physiological
changes, such as during breath holding (which increases the CO2 in the blood), exercise (which increases
lactic acid in the blood), or when gastric acid is secreted.
Respiratory control
The pH of blood during normal conditions is 7.4. However, CO2 dissociates into carbonic acid in
the tissues. Thus, presence of more CO2 makes the blood more acidic. That is the reason when
