THE URINARY SYSTEM; ANATOMICAL, PHYSIOLOGICAL AND CLINICAL EXPLANATION

Comments Anatomical: The urinary system consists of two kidneys, two ureters, one bladder and one urethra. Physiological: The urinary system has vital excretory functions, such as the formation of urine to maintain water and electrolyte homoeostasis (water, electrolyte and acid–base balance), the excretion of metabolic waste products (nitrogenous compounds such as urea, creatinine and uric acid, ions in excess of body needs and some drugs), the secretion of erythropoietin (a hormone stimulating the production of red cells), the secretion of renin (an enzyme critical for the control of arterial blood pressure) and the transport and storage of urine. Clinical: The bladder fills with urine at the rate of about 60 mL per hour. The collection of urine every hour or every 24 hours allows renal function to be monitored. Signs and symptoms suggestive of obstruction in the tract or of renal disease (e.g., renal stones, infections and other lesions) include severe pain in the lumbar region, increase in volume and frequency of urination, oliguria (a urine volume <400 mL in 24 hours), anuria (absence of urine), pyuria (pus in the urine) and haematuria (blood in the urine). There may be other signs, such as oedema and arterial hypertension.