Hyponatremia feedback loop is overwhelmed by increased fluid intake, 2) the feedback loop malfunctions such that ADH is always "turned on"; 3) the receptors in the kidney are always "open" regardless of there being no signal from ADH to be open; or 4) there is an increased ADH even though there is no normal stimulus (elevated serum sodium) for ADH to be increased. Hyponatremia occurs in one of two ways: either the osmoreceptor-aquaporin feedback loop is "overwhelmed", or it is "interrupted". If it is interrupted, it is either "related" or "not related" to ADH. If the feedback system is overwhelmed, this
Serum (blood) Serum (blood) In blood, the serum () is the component that is neither a blood cell (serum does not contain white blood cells- leukocytes, or red blood cells- erythrocytes), nor a clotting factor; it is the blood plasma not including the fibrinogens. Serum includes all proteins not used in blood clotting and all the electrolytes, antibodies, antigens, hormones, and any exogenous substances (e.g., drugs and microorganisms). The study of serum is serology. Serum is used in numerous diagnostic tests, as well as blood typing. Measurements of serum concentrations has proved useful in many fields including clinical trials of therapeutic vs