The Urinary System

The Urinary System Also called the renal system or excretory system. Maintains the proper amount of water in the body. Removes waste products from the blood by excreting them in the urine. Consists of the kidneys, ureters, urinary bladder, and urethra.

Filtering the Blood The urinary system contains the organs that remove waste products from your blood. The Kidneys as Filters The kidneys are a pair of organs in the urinary system that clean the blood and excrete products as urine. Inside each kidney are more than 1 million microscopic filters called nephrons. Nephron, functional unit of the kidney (each kidney has more then needed which is why humans can live with 1 kidney), the structure that actually produces urine in the process of removing waste and excess substances from the blood Average adult kidneys filter about 1,7000 quarts of blood daily and create about 1.5 quarts of urine. Blood enters each kidney through the renal artery and exits through the renal vein. Kidneys form urine for excretion and retain substances the body needs. Urine begins forming with the filtration of water, salts, sugar, urea, and other waste from the blood.

Filtering the Blood One large artery (the renal artery) enters the kidney, carrying blood with water and waste products These substances are pulled from the artery into nephrons As the substances flow through the nephrons, much of the water is absorbed back into the blood vessels, while the waste remains in the kidney

Filtering the Blood The blood vessel that exits the kidney (the renal vein) usually lacks a small amount of water and a large amount of waste products. The waste that remains in the kidney is a very concentrated solution called urine. Urine leaves the kidney through a small tube called the ureter, where it will flow to the bladder.

The Parts of the Urinary System Kidneys – form urine for excretion. Ureters – transport urine from the renal pelvis to the urinary bladder. Urinary bladder – hollow, muscular organ that stores urine until excreted. Urethra – smooth muscle tube for voiding, or micturition of urine. Male urethras are longer then females.

Water in, Water Out Sweat and Thirst The evaporation of water in the form of sweat cools you down. As the water content of the blood drops, the salivary glands produce less saliva, resulting in thirst. Antidiuretic Hormone When you get thirsty, antidiuretic hormone is released. This hormone signals the kidneys to take water from the nephrons and return it to the bloodstream.

Water in, Water Out Diuretics Some beverages contain caffeine, which is a diuretic. Diuretics cause the kidneys to make more urine, which decreases the amount of water in the blood.

Jobs & Professions Urologist- Specialize in issues related to the male and female urinary tracts and male reproductive organs. Nephrologist- also called a renal physician. Someone who specializes in treatment of patients with kidney disease. Dialysis Technician- primary caregiver for patients who are undergoing dialysis, process through which waste products are filtered from the blood when the kidneys are not functioning properly.

Diseases and Disorders

Kidney stones (renal calculi). Kidney stones are hard pebble like obstructions in your urinary tract Kidney stones are a buildup of crystallized salts and minerals such as calcium in the urinary tract. A stone commonly forms in the kidney when a person becomes dehydrated and the urine becomes concentrated. Kidney stones form when your urine contains more crystal-forming substances — such as calcium, oxalate and uric acid — than the fluid in your urine can dilute.  Avoid stone-forming foods: Beets, chocolate, spinach, rhubarb, tea, and most nuts are rich in oxalate, and colas are rich in phosphate, both of which can contribute to kidney stones. 

Causes Recurrent urinary tract infections Drinking too little fluid A blockage of the urinary tract Limited activity for several weeks or more Consuming too much calcium, oxalate, or uric acid in your diet Consuming too much vitamin C or D Certain medications Certain metabolic diseases

Treatment Options Kidney stones usually pass through the urinary tract on their own They may need to be removed surgically

Cystitis An inflammation of the bladder or urinary tract infection (UTI) Bacterial infection that can occur anywhere in the urinary tract, from the kidney to the urethra. Most common occurrence is in the bladder. Also called a bladder infection.

Symptoms include: Treatment options: Vary depending on the source of the infection Painful urination Cloudy urine Frequent need to urinate Treatment options: Antibiotics usually treat the infection and with treatment the infection will clear up in about two weeks

Pyelonephritis (bacterial infection) Usually from bacteria that have spread from the bladder. Causes: infections in the bladder use of a catheter to drain urine from the bladder use of a cystoscope to examine the bladder and urethra surgery on the urinary tract conditions such as prostate enlargement and kidney stones that prevent the efficient flow of urine from the bladder defects or abnormalities in the urinary tract that block the flow of urine

Symptoms back, side, and groin pain urgent, frequent urination pain or burning during urination fever nausea and vomiting pus and blood in the urine

Diagnosis Diagnosis is made with a urine test to identify bacteria and formations of white blood cells, called casts, shaped like tubes in the kidneys. If an infection cannot be easily cured, x rays might be done to look for abnormalities in the kidneys, ureters, and bladder.

Treatment A kidney infection is treated with an appropriate antibiotic taken for several weeks. Anatomic abnormalities may need to be surgically treated. Severely ill patients with kidney infections may be hospitalized until they can take fluids and needed drugs on their own. Various drugs are available to relieve the pain of a kidney infection. A heating pad may also help.

Glomerulonephritis (kidney inflammation) Also called nephritis Tiny filters in the kidney that help to clean the blood become inflamed or damaged Causes: Infection Certain drugs Cancer Most often the cause is unknown

Treatment Options Medications May disappear on its own Untreated kidneys may be slowly destroyed

Symptoms High blood pressure Excessive foaming of the urine Change in the color of the urine (to red or dark brown) Puffiness of the eyes, hands and feet. Vomiting Difficulty breathing Headaches

Kidney or renal failure The filtering of the blood by the kidneys is either slowed or stopped. Causes waste products to build up in the blood Acute Sudden Renal Failure May be due to bacterial infection, injury, shock, heart failure, poisoning, or drug overdose. Treatment may include dialysis or surgery

Chronic Renal Failure The kidneys lose their ability to function over a period of time. If diagnosed early, it can be treated but not reversed. Usually requires a kidney transplant. Dialysis is a process that does the job of the kidneys. Dialysis machines remove toxic waste from a person’s body, when that person’s kidneys are unable to.

Incontinence Weakening of the muscles and sphincter of the bladder Causes leaking of bladder contents at inappropriate or unexpected times