Excretory System

Removing Metabolic WasteExcretion:

Do Now – Name as many wastes as you can that must leave the body in order to be healthy

To remove waste from the body. It includes the SKIN, LIVER, KIDNEYS, and LUNGS.

The SKIN removes heat from the body by releasing SWEAT which evaporates and cools our body.

The skin also removes some of the same substances as urine including urea and salts.

EXCRETORY SYSTEM FUNCTION

Regents QuestionWhich human excretory structure aids in

the maintenance of normal body temperature?

1)Urinary bladder

2)Nephrons

3)Liver

4)Sweat glands

Regents Answer

4)Sweat glands

What is Cellular Waste? Cellular waste is one of the products of

cellular metabolism. These materials are: excess water and salts,

carbon dioxide, and urea. They must be eliminated from the

organism or they can lead to its death.

When carbon dioxide builds up in the blood, the brain signals the lungs to inhale and exhale.

Carbon dioxide, a little water vapor and heat are removed as waste products by the lungs.

Cellular Waste

The Urinary Tract

The renal artery brings oxygen rich, ‘dirty’ blood to the kidneys.

The kidneys remove toxins, waste and excess water from the blood.

The urine is sent from the kidney through the ureters to the bladder where it leaves the body through the urethra.

Regents QuestionWhich sequence represents the correct

pathway for the removal of urine from the human body?

1)Kidney-ureter-urinary bladder-urethra

2)Kidney-uretra-urinary bladder-ureter

3)ureter-kidney-urinary bladder-urethra

4)urethra-kidney-urinary bladder-ureter

Regents Answer

1)Kidney-ureter-urinary bladder-urethra

Ascending Loop

Glomenulus Descending

Loop

Bowman Capsule

The Kidney The kidney is an excretory organ composed of many working units called nephrons.

Each nephron will filter the organisms blood and concentrate the cellular waste for removal.

The nephrons filter the blood and send theUrine to the ureters to the bladder where it isexcreted via the urethra.

How the Nephron Works Bowman’s Capsule &

Loop of Henle

The capsule will take out water, amino acids, glucose, salts, and urea.

The Loop of Henle will reabsorb the amino acids, glucose and, salt. (makes urine concentrated)

Ascending Loop

Glomenulus Descending

Loop

Bowman Capsule

http://video.about.com/surgery/Kidney-Transplant.htm

Regents QuestionIn humans, which substance is normally

excreted through both alveoli and nephrons?

1)Water

2)Ammonia

3)Glucose

4)Uric acid

Regents Answer

1)Water

The Liver The liver makes bile to

emulsify fats. The liver filters the blood

to remove the dead red blood cells

The liver makes digestive enzymes.

The liver makes some amino acids

The liver removes toxic ammonia by turning it into urea and excreted as part of the urine.

Elimination from the Body The concentrated urine will be dumped

into the collecting tubules of the kidney. Each kidney will pass the urine to a large

muscular organ called the urinary bladder via tubes called ureters.

The Bladder will eliminate the urine from the body via a tube called the urethra.

The Large Intestine Undigested food in a solid form passes to the large intestine

Water is reabsorbed into the body from the undigested material

Solid waste is stored until it is excreted from the body.

Summary of the Excretory System Video Clip