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.
Aldosterone (aka mineralocorticoid): Adrenal glands release aldosterone, causes kidney (distal tubules) reabsorb more Na+, which in turn causes more water reabsorption. ADH (made in hypothalamus, stored in pituitary): causes more water reabsorption in the kidney tubules, raising blood pressure.