Urinary System

1. Urinary System The bodily system consisting of the organs that produce, collect, and eliminate urine and including the kidneys, ureters, urinary bladder, and urethra.

2. Summary In the human body, the urinary system is composed of the two kidneys, the ureters, the bladder and the urethra. The main function of the urinary system is to maintain homeostasis or the state of balance in our body. This balance is vital for the proper functioning of the human body. The urinary system maintains a constant internal environment of the body by regulating the body's fluid and electrolyte balance ensuring body waste is removed. Diseases of the urinary system interfere with the way the urinary system works and this creates chaos. Some of the most common diseases of the urinary system are discussed below.

3. Major Organs • 2 Kidneys • Bladder • 2 Sphincter muscles • Ureter • Urethra

4. About the Organs • two ureters - narrow tubes that carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters. • bladder - a triangle-shaped, hollow organ located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra.

5. About the Organs(page 2) • two sphincter muscles - circular muscles that help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder. • nerves in the bladder - alert a person when it is time to urinate, or empty the bladder. • urethra - the tube that allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

6. The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney. Kidneys & Nephrons

7. Nephrons – the main cells in the Urinary Tract The Nephrons filter blood to form urine.

8. Glomerulus The glomerulus is within the Nephron, where blood is filtered to form urine. The glomerulus is a network of capillaries that helps perform the first step of filtering blood.

9. Bowman’s Capsule Bowman’s capsule is a cup-like sac at the beginning of the tubular component of a nephron in the kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule and further processed along the nephron to form urine. This process is known as ultrafilteration.

10. Urinary Tract Infection (UTI) Urinary tract infections in the human body are most commonly caused by bacteria that affect part of the urinary tract. When it affects the lower urinary tract, the medical condition is known as simple cystitis. An upper UTI is potentially more dangerous than a lower UTI. Symptoms of a lower urinary tract infection include painful urination and frequent urination. The symptoms of an upper UTI include fever and pain in the lower abdomen. Urinary tract infections are more common in women than in men. Risk factors for the disease include female anatomy, sexual intercourse and family history.

11. Renal failure or kidney failure Formerly referred to as renal insufficiency, renal failure is the medical term used today to describe a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood. Biochemically, this urinary system disease is detected by an elevated serum creatinine level. Problems encountered when the kidneys fail to function as they should include deranged acid levels, abnormal levels of calcium and phosphate and delayed healing in broken bones. Hematuria and proteinuria may also occur.

12. Kidney Stones A kidney stone also known as a renal calculus is a crystal aggregation that sometimes forms in one or both kidneys of a person. These solid lumps are typically classified based on their location in the kidney, ureter and bladder and also by their chemical composition. Kidney stones are a significant source of morbidity. Statistically this urinary system disease most commonly affects men.Interstitial cystitis

13. Interstitial cystitis Chronic disease of the urinary bladder. It is often characterized by pain associated with the bladder, an increased urinary frequency and urgency and pressure in the bladder. Interstitial cystitis can have a profound impact on quality of life. As a matter of fact, a study at the University of Harvard concluded that the impact of interstitial cystitis is both so severe and debilitating that the condition is now officially recognized as a disability. Interstitial cystitis affects men and women of all cultures, backgrounds and ages.

14. Benign prostatic hyperplasia Benign prostatic hyperplasia also known as benign prostatic hypertrophy or benign enlargement of the prostate is an increase in size of the prostate. The disease is characterized by hyperplasia of prostatic stromal and epithelial cells. This results in the formation of large nodules in the prostate. When sufficiently large, the nodules compress the urethral canal to cause partial and sometimes complete obstruction of the urethra. This leads to symptoms of urinary hesitancy, painful urination and increased risk of urinary tract infections. Benign prostatic hyperplasia, unlike popular beliefs, does not lead to cancer.