Urinary System
The urinary excretory system is responsible for filtering and removing liquid waste from the body. The two main organs of the urinary system are:
- The Kidneys and Ureters
- The Bladder and Urethra
Blood is filtered by the glomerulus which is located within the kidney outer layer called the cortex. Fluid leaving the glomerulus then passes through the proximal and distal convoluted tubules which reabsorb most of the filtered water, sodium, glucose, peptide hormones, protein, potassium, amino acids and phosphate. The resulting concentrated urine then enters the renal collecting system and is transferred to the bladder by the ureters. Urine is periodically voided from the bladder via the urethra. The kidneys filter about 1,600 liters of blood each day and creates about 900 cc of urine.
The main waste product filtered by the kidney is urea, which consists mainly of nitrogen. Other constituents normally found in the urine are:
- Creatinine
- Sodium
- Chloride
- Potassium
- Magnesium
- Calcium
Abnormal constituents of the urine may include:
- RBCs
- WBCs
- Bacteria
- Ketones
- Glucose or other sugars
- Fat
- Excess Protein
- Bilirubin
Decreasing renal function progresses through four stages: Diminished renal reserve, renal insufficiency, renal failure and end-stage renal disease. Disorders of the bladder include congenital abnormalities, inflammatory conditions and tumors.