The urinary system serves as the body's drainage system, eliminating urine composed of waste and excess fluid. To ensure proper urination, all components of the urinary system must function harmoniously and in the correct sequence.
This network of interconnected tubes and ducts is linked to blood vessels and the digestive system. By facilitating waste removal, the urinary system plays a vital role in maintaining overall bodily functions.
Parts of the Urinary System
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDKK), the urinary system is composed of a bladder, two kidneys, two ureters, and a urethra. Cooperation between these parts is needed to function properly and facilitate normal urination.
Kidneys: These are two fist-sized, bean-shaped organs located below the rib cage. They are responsible for filtering 120 to 150 quarts of blood daily to remove waste and maintain fluid balance, resulting in 1 to 2 quarts of urine production per day.
Ureters: These are thin muscular tubes connecting the kidneys to the bladder, transporting urine from the kidneys to the bladder.
Bladder: This is a hollow, muscular organ situated in the pelvis between the hip bones, expanding as it fills with urine. It acts as a reservoir, capable of holding 1.5 to 2 cups of urine. The control over emptying the bladder, known as urination, lies with the individual.
Urethra: It is a tube located at the base of the bladder, allowing urine to exit the body during urination.
Aside from these main parts, the urinary system also has sphincter muscles. The urinary tract has two sets of muscles acting as a sphincter. The internal sphincter muscles at the bladder neck and urethra remain closed until signals from the brain initiate urination.
Meanwhile, the external sphincter muscles, surrounding the internal sphincter, apply additional pressure to keep the urethra closed. Conscious control over the external sphincter and pelvic floor muscles helps prevent urine leakage.
How Is Urine Produced?
Urine is produced by your kidneys, which filter waste and excess water from your blood, with the waste known as urea. Medline Plus explained that this waste is transported through your bloodstream to the kidneys. From there, urine passes through two slender tubes called ureters, eventually reaching the bladder.
The bladder serves as a reservoir for storing urine until you are ready to urinate. It expands into a round shape when it is full and contracts to a smaller size when it is empty. In a healthy urinary system, the bladder can comfortably hold up to 16 ounces (2 cups) of urine for 2 to 5 hours.
The brain sends signals to the sphincters, instructing them to relax, and triggers the muscular bladder wall to contract, forcing urine through the urethra and out of the bladder. The frequency of urination depends on the speed at which the kidneys produce urine and the bladder's capacity to hold it comfortably.
While the bladder fills with urine, the muscles of the bladder wall remain relaxed, as the sphincter muscles stay contracted to retain urine within the bladder. As the bladder continues to fill, signals are sent to the brain, prompting the individual to locate a toilet promptly.
Urinary problems, such as difficulties with urination, blood or protein in the urine, and bladder control issues, can arise from various conditions like kidney failure, urinary tract infections, enlarged prostate, bladder control problems, or bladder blockage. Seeking medical attention for diagnosis through urinalysis and other tests is crucial for appropriate treatment.
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