May 28, 2022
Urine (Latin urina) - urine, fluid produced in the kidneys and excreted from the body, containing metabolic products that are useless or harmful to the body. It is formed during filtration and resorption. The daily amount of urine excreted by a healthy person ranges from 600 to 2500 ml. It depends on many factors, including the amount of fluids consumed and the ambient temperature. The urine consists of: 96% water; 2.5% of nitrogenous metabolic products (urea, uric acid, ammonia); 1.5% mineral salts (chlorides, phosphates, carbonates); minimal amounts of other substances, e.g. bile pigments (they give urine color, smell and taste). Urine of a healthy person should not contain sugars, proteins, red and white blood cells and bacteria. The presence of any of these factors could be a symptom of an illness: sugar in the urine may mean glycosuria - a symptom of diabetes mellitus; protein in the urine may be proteinuria - liver problems (e.g. jaundice); lymphocytes and bacteria in the urine - symptom (e.g. pyonephrosis). Diseases related to urine excretion: diabetes insipidus kidney stones. Urine discharge is regulated by the nervous system (by the brain, cortex and the vegetative system) and by vasopressin (an antidiuretic hormone secreted by the pituitary gland), and is also related to the circulatory system. Urine flows out as the bladder muscles contract and the bladder sphincter relaxes. In fact, it is a reflex act that a person learns to control at the age of 1.5 years. An overly full bladder causes involuntary urination, sometimes also during sleep (also in adults). Some animals, including birds, urinate unconditionally, although conditional urination can be taught through training. The formation of urine: The renal artery supplies the kidney with blood with urea, excess water and other unnecessary and harmful substances. This blood enters the cortical layer of the glomeruli. The blood is filtered in the glomeruli. Primary urine is resorbed in the renal tubules - that is, the absorption of valuable substances from the primary urine into the blood (glucose, vitamins, mineral salts, water). Final urine flows from the renal tubules and into the collecting tubules. Urine passes from the renal pelvis to the ureters. The urine flows through the ureters into the bladder. The urine is passed out of the body through the urethra.