The Urinary System

The Organs in the urinary system are: Kidneys Ureter Urinary Bladder Urethra

Purpose of the Urinary System There are two purposes to the Urinary System: Filtration Reabsorbing Water

Filtration Filtration of blood occurs in the kidney. Within the kidney nephrons facilitate the filtration process. Each nephron has a cup shaped structure called a Bowman’s capsule that encloses a bed of capillaries. This bed called a glomerulus, receives blood from the renal artery. Materials from the blood are forced out of the glomerulus and into the Bowman’s capsule during the filtration process.

Filtration Materials such as water, urea, glucose, vitamins, and salts move from the Bowman’s capsule in to the renal tubule. The renal tubule has three parts: the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule. These components act to reabsorb water/nutrients, secrete toxic substances, and form urine. The fluid wastes that remain in the distal convoluted tubule form urine.

Reabsorbing Water: Purpose #2 The filtrate flows through the renal tubes. Then these materials return to the blood by being selectively transported through the walls of the renal tubule and entering the surrounding capillaries. Most reabsorbing of the water occurs in the proximal convoluted tubule.

The three parts of the kidney are Kidney Parts The three parts of the kidney are Cortex-makes up a third of the kidneys tissue mass, located on the outer layer of the kidney. Medulla- makes up the inner two thirds of the kidney. Pelvis- is the funnel shaped structure in the center of the kidney.

Kidneys:Functions and Location Balance the body's water content. • Remove waste products from the blood. Waste products come from body cells and foods that are eaten. • Help keep body chemicals in balance. Kidneys are located in the small of the back on located behind the stomach and one located behind the liver.                                                    

Ureter: Location and Function There are two uterine tubes that carry urine from the kidneys to the bladder. Each ureter is about ten to twelve inches long. Urine flows down partly by gravity, but mainly by waves of contractions which pass several times per minute through the muscle layers of the urethral walls. Each ureter enters the bladder through a tunnel in the bladder wall, which is angled to prevent the urine from running back into the ureter when the bladder contracts. It is found in-between the kidney and the urinary bladder.

Urinary Bladder: Function and Location The bladder is a muscular sac that stores urine after it has come from the kidney. Muscular contractions of the urinary bladder force urine out of the urethra. The ureter is the tube that leads to the urinary bladder from the kidney containing urine.

Urethra: Function and Location The urethra is a tube that conveys urine from the urinary bladder to the outside of the body. Its wall is lined with mucous membranes and contains a relatively thick layer of smooth muscle tissue. It also contains numerous mucous glands, called "urethral glands," that secrete mucus into the urethral canal. It passes forward from the bladder and empties into the labia minor. It is located after the urinary bladder where the urine is forced in to the urethra.

Clinical Conditions: Kidney Stones Salt crystals form into insoluble stones (renal caliculi) Insufficient water intake Shock wave treatment - bombarded by sound waves Pass through water tank into tissues

Clinical Conditions: Incontinence Lack of voluntary control of urination Nerves to external urethral sphincter not developed in babies

Clinical Conditions: Glomerulonephritis Inflammation of glomerulus Filter becomes permeable to RBC’s and protein Caused by Streptococci toxins May cause permanent damage ----> kidney failure

Clinical Conditions: Pyelitis Inflammation of renal pelvis and calyces In association with UTI in females Usually caused by E. coli

Clinical Conditions: Cystitis Bladder infection or injury Burning or painful urination Low back pain

Clinical Conditions: Proteinuria Protein in the urine (albumin) Due to increased permeability of glomerular filter Swelling results as H2O move into interstitial spaces Diabetes, infections, heavy metals, drugs, sickle cell anemia

Clinical Conditions: Acute Renal Failure Kidneys stop functioning abruptly Low blood volume or damaged kidney (stones)