Intracellular = inside cells
Extracellular = outside cells
Plasma = pretty much same as "blood"
Lymph = something else that goes around the body in little tubes
Interstitial = tissue fluid
Transcellular = "across cells"
Cerebrospinal fluid = thin layer of liquid that cushions your brain and spinal cord
Synovial fluid = lubricating your joints
Pleural fluid = lubricating your lungs
Peritoneal fluid = around your bones
Intraoccular fluid = in your eyes
Digestive secretions = stomach juice, pancreatic juice, saliva, etc. etc.
Take-home message of diagram 1: water is very important. Don't take diuretics or get dehydrated. Water weight = totally worth it.
Interesting, no? :)
In other words, if you drink a lot of water with salts in, and the concentration is that same as the concentration of your extra-cellular fluid, then you don't pee very much extra. When we got taught this I immediately thought of all of you who panic about getting weighed at the doctor's. A good "tip" would be to drink isosmotic saline - little increase in pee (at least until much later), much increase in weight.