At all the mammals and thus the Man, iturinate is a biological liquid secrété by by filtration of . Famillièrement, one calls it "piss" or "wee".
Production of the urine
Blood arterial who penetrates the kidneys by the renal artery ends up joining the basic unit of the renal machinery: the cluster. Each day, the kidneys filter 180 liters of blood and produce on average 1500 ml of urine. In the renal cluster, blood is filtered by an osmotic phenomenon: it discharges out of water and mineral and biological substances. This primary urine walks on in a system of tubules (tube circumvented proximal, handle of Henle, tube circumvented distal) where it is successively enriched in various compounds, and on the contrary débarassée of certain substances recovered by the organization (water, , rock salt in particular). The phenomena of excretion and reabsorption are regulated by several hormones, of which itanti-diurétique hormone. The urine which circulates in all the distal circumvented tubes is collected on the level of the tubes of Bellini, then it joined the renal chalices, and them uretères. There, it joined bladder by jets (there is a valve anti-backward flow between uretère and bladder). When the vesical contents exceed a certain threshold, the desire for urinating is transmitted to the brain, in order to empty the bladder by the micturition.
Composition of the urine
- Water: 95%
- Composed organic:
Abnormal components of the urine:
- (one speaks abouthémoglobinurie)
- Red blood corpuscles (one speaks abouthématurie)
- (one speaks about protéinurie)
Functions of the urine
- Purification of waste of the cellular metabolism,
- Purification of the poisons with renal elimination,
- Maintenance of the plasmatic volemy and thus of ,
- Maintenance of balance electrolytic,
- Maintenance of physiological pH by maintenance of the urinary acido-basic plug,
- Acidosis (pH < 7.38) is prevented by quaternary ammonium elimination NH4+,
- Alcalose (pH > 7.42) is prevented by the bicarbonate HCO3 elimination -.
- urinary system
- The urine in sexuality: