The Excretory System (2:09) Click here to launch video Click here to download print activity

The excretory system removes wastes from the body.

nephrons ureters urethra cystitis urethritis hemodialysis

How Excretion Works The excretory system uses several organs to remove all types of wastes from the body. The body produces wastes in the form of solids, liquids, and gases that must be removed so that the body can function well.

The Lungs, Skin, and Large Intestine The large surface area of your skin allows you to excrete water and salts when you sweat.

The Lungs, Skin, and Large Intestine Solid wastes are eliminated through the large intestine. Sweating is a form of excretion that helps to regulate body temperature. The lungs expel carbon dioxide when you exhale.

The Liver The liver is the first organ to receive chemicals absorbed from the small intestine. The liver detoxifies the body by processing and excreting into bile toxins such as drugs, alcohol, and some cellular waste products.

The Urinary System The Parts of the Urinary System Kidneys Bladder Ureters Urethra

The Urinary System The main function of the urinary system is to filter waste and extra fluid from the blood. Urine is liquid waste material excreted from the body. It consists of water and body wastes that contain nitrogen.

The Kidneys The kidneys remove waste products from the blood through tiny filtering units called nephrons. Nephrons The functional units of the kidneys

The Kidneys The kidneys adjust the amount of salts, water, and other materials excreted according to the body’s needs. In this way, the kidneys monitor and maintain the body’s acid-base and water balances.

The Kidneys The kidneys perform the vital function of removing waste from the blood. KidneyNephron

The Ureters Urine travels from the kidneys to the bladder through the ureters about every 15 seconds. Ureters Tubes that connect the kidneys to the bladder

The Bladder and Urethra The bladder stores about 2 cups of urine comfortably for two to five hours. Sphincter muscles help keep urine from leaking.

The Bladder and Urethra The bladder’s sphincter muscles close tightly like a rubber band around the opening of the bladder into the urethra. Urethra The tube that leads from the bladder to the outside of the body

Maintaining Your Excretory Health Healthful behaviors will help keep your excretory system healthy. The excretory function removes wastes that can become toxic from the body.

Maintaining Your Excretory Health Limit your intake of caffeine and soft drinks, which can increase the amount of water lost through urination. Drink at least eight 8-ounce glasses of water each day. Tips for Maintaining Your Excretory Health Follow a well-balanced eating plan. Practice good hygiene. Get regular medical checkups.

Excretory System Problems Excretory system problems commonly result from infection or blockage. Disorders of the excretory system can have several different causes, including infection, blockage of urine, or natural aging.

Excretory System Problems Cystitis and urethritis are usually caused by a bacterial infection. Left untreated, the infection can spread to the kidneys. Cystitis Inflammation of the bladder

Excretory System Problems Symptoms of cystitis and urethritis include burning pain during urination, increased frequency of urination, fever, and possibly blood in urine. Urethritis Inflammation of the urethra

Kidney Problems Nephritis Inflammation of the nephrons. Kidney Stones Salts in the urine crystallize into solid stones and move into the ureter, causing pain and blocking the passage of urine. Uremia Decreased blood filtration by the kidneys leads to abnormally high levels of nitrogen waste products remaining in the blood.

Kidney Failure Kidney failure occurs when the kidneys lose their ability to function. It can be caused by infection, decreased blood flow, or diseases that damage kidney tissue.

Kidney Failure Hemodialysis takes three to five hours and is done three or four times per week. Hemodialysis A technique in which an artificial kidney machine removes waste products from the blood

Kidney Failure Peritoneal dialysis uses the peritoneum, a thin membrane that surrounds the digestive organs, to filter the blood.

Kidney Failure Kidney transplant involves the replacement of a nonfunctioning kidney with a healthy kidney from an organ donor.

After You Read Reviewing Facts and Vocabulary The main function is to remove all types of waste from the body. The organs include the large intestine, lungs, skin, liver, kidneys, and bladder. 1.What is the main function of the excretory system? What organs are part of it?

After You Read Reviewing Facts and Vocabulary 2.How are a ureter, a urethra, and urethritis different? A ureter is a tube that connects a kidney to the bladder. The urethra leads from the bladder to outside the body. Urethritis is an inflammation of the urethra.

After You Read Reviewing Facts and Vocabulary 3.How can you prevent cystitis and urethritis? Practice good hygiene and personal health to prevent harmful bacteria and infection.