The captured Africans were held in forts, sometimes called 'slave castles', along the coast. They remained there for months until finally leaving their homeland for an unknown destination on board European merchant ships, including those of the British Royal African Company.
Key Points. 1  The majority of fluid output occurs from urination. Some fluid is lost through perspiration (part of the body's temperature control mechanism) and as water vapor in expired air. 2  The body's homeostatic control mechanisms ensure that a balance between fluid gain and fluid loss is maintained.
Urine, which is produced by the kidneys, contains the byproducts of metabolism â salts, toxins, and water â that end up in the blood. The kidneys and urinary tract (which includes the kidneys, ureters, bladder, and urethra) filter and eliminate these waste substances from our blood.