Harmless and beneficial bacteria far outnumber harmful varieties. Thousands of bacterial species live commensally in humans, and many provide health benefits to humans, aiding in digestion, for example, or helping to prevent the establishment of colonies of pathogenic bacteria.armless and beneficial bacteria far outnumber harmful varieties. Thousands of bacterial species live commensally in humans, and many provide health benefits to humans, aiding in digestion, for example, or helping to prevent the establishment of colonies of pathogenic bacteria.
ADH (Antidiuretic Hormone) The brain and kidneys regulate the amount of water excreted by the body. When the blood volume is low, the concentration of solutes in the blood is high. When the hypothalamus senses this low blood volume and increased serum osmolality it synthesizes ADH, a small peptide molecule.
1 If the body is becoming fluid-deficient, this will be sensed by osmoreceptors, which results in increased secretion of ADH, causing fluid to be retained by the kidneys and urine output to be reduced.  The hormones ADH (Anti-diuretic Hormone, also known as vasopressin) and aldosterone play a major role in this.