The human body gains and loses fluids through several key processes: Fluid Gains:
- Ingestion: Drinking water and other beverages provides most body fluids.
- Absorption: Water is absorbed from food in the digestive tract.
- Metabolic processes: A small amount of water is produced internally as a byproduct of metabolism.
Fluid Losses:
- Urination: The kidneys filter blood and excrete excess water and waste as urine.
- Sweating: Water is lost through the skin to help regulate body temperature.
- Respiration: Water vapor is lost when breathing out from the lungs.
- Defecation: Water is also lost with feces, though to a lesser extent.
These processes maintain water balance essential for cell function and overall health. Hormonal regulation, such as antidiuretic hormone release, adjusts kidney water excretion based on hydration status, promoting retention during dehydration and excretion when excess fluid exists. Thus, the human body gains fluids mainly by drinking and absorbing them, alongside metabolic generation, and loses fluids primarily through urine, sweat, breathing, and feces excretion.
