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.
Either the kidneys can conserve water by producing urine that is concentrated relative to plasma, or they can rid the body of excess water by producing urine that is dilute relative to plasma. Direct control of water excretion in the kidneys is exercised by vasopressin, or anti-diuretic hormone (ADH), a peptide hormone secreted by the hypothalamus.