Body Fluid Flashcards
What is the proportion of body weight accounted for by water?
~60%
High body weight: ~40%
Low body weight: ~80%
How is body water regulated?
Hormonal mechanisms, circulatory mechanisms and renal mechanisms
What is water balance?
Water intake and water loss are equal to each other
What is intracellular fluid and the extracellular body fluid water composition?
Intracellular fluid (inside the cell): ~2/3rds of total body water
Extracellular fluid (outside the cell): ~1/3rd of total body water
ECF is subdivided into TWO major compartments. What are they?
Interstitial fluid (fluid between cells) ~80%
Plasma (fluid in circulatory system) ~20%
What’s the total volume of water in intracellular fluid?
~27l
What’s the total volume of water in interstitial fluid?
~11l
What’s the total volume of water in plasma fluid?
3-3.5l
What volume is needed for water intake and where does it come from?
Metabolic water: 200ml/per day
Food and drink: 1.5l - 2.5l/ per day
Where do we lose water and what is the approximate volume lost per day?
Kidneys: 0.5 - 1.5 l/day
Lungs: 0.3 - 0.4 l/day
Skin & sweat: 0.2 - 1.0 l/day
Faeces: 0.1 - 0.2 l/day
Is the protein content of plasma higher or lower than the interstitial fluid?
Higher, because proteins are too large to pass through the pores in the capillary walls.
What happens when plasma osmotic pressure falls?
When the plasma volume falls, the fluid will move from the plasma into the interstitial spaces. This can cause oedema.
What causes plasma osmotic pressure to fall?
Severe starvation - low protein intake
Where is the cerebrospinal fluid found?
In spaces within the brain and the surrounding portions of the brain and spinal cord.
What is the CSF volume?
~150ml
