In fact, a urine test is a simultaneous assessment of two processes. The first is the filtration of urine through the glomeruli, the second is the absorption of fluid in the renal tubules. The tubular (tubular) secretion also joins the latter. The filtrate contains plasma constituents (sodium, potassium, chlorine, calcium, magnesium, urea, glucose) in an isotonic plasma solution. Electrolytes and other substances soluble in water are absorbed from this liquid in the tubules, as well as liquid, and in large quantities, so that the amount of urine excreted in 24 hours is only about 1 liter. In the proximal part of the tubules, sugar, amino acids and phosphates are absorbed, and in their distal part — the regulation of water-salt metabolism, the formation of ammonia. The last part of the renal nephron is the site of regulation of sodium, potassium and water metabolism. Here the antidiuretic hormone of the pituitary gland and aldosterone manifest their effect. The amount of urine depends on the function of the vessels leading to the nephron, the filtration capacity of the glomeruli, the function of the tubules, the state of the urinary tract. Filtration in the glomeruli depends on filtration pressure, that is, on blood pressure, and the function of the tubules depends on the action of certain hormones, which, in turn, are subordinated to the activities of various regulatory centers and centers of the central nervous system. The amount of urine may be higher than normal (polyuria) and lower than it (oliguria). With significant polyuria or oliguria, the patient himself notices these changes. In other cases, the carefully collected amount of daily urine determines what the function of the kidneys is. Polyuria can usually be spoken of if more than 1 liter of urine is excreted per day, and oliguria — if less than 400 ml of urine is excreted per day. The bladder usually holds 200 — 400 ml of urine. When it is filled, as a result of the tension of the walls, a reflex mechanism comes into effect, causing the urge to urinate. Usually, such urges — depending on various conditions, for example, on established habits — there are 4-5, if they appear more often, they say pollakizuria, or frequent urination. Pollakizuria can be combined with polyuria, oliguria, and may also occur with a normal amount of urine excreted. The most common cause of this pathology is anatomical changes in the urinary tract, their inflammation, possibly an obstacle to the excretion of urine. Frequent urination can also be painful. Difficult urination is called dysuria, prolonged urine excretion is called opsiuria. Erotic massage
