The Excretory System

Excretory Excretory SystemSystem

Life ScienceLife Science

The function of the ExcretorySystem is ridding the body of waste.

Excretory SystemExcretory SystemThe removal of something is The removal of something is excretion.excretion.

• The main organs of the excretory system are the bladder, kidneys, lungs, liver and skin.

• The excretory system is like the sewage system because the excretory system gets rid of waste that the body does not need. The body also gets rid of natural gasses which can be fatal if not released from the body.

KidneysKidneys• One of the main jobs of the kidneys

is to filter the waste out of the blood. • The kidneys filter that blood as many

as 400 times a day! More than 1 million tiny filters inside the kidneys (nephrons) remove the waste.

WasteWaste• The waste that is collected combines with

water (which is also filtered out of the kidneys) to make urine (pee). Each day, your kidneys produce about 1.5 liters of urine.

• As each kidney makes urine, the urine slides down a long tube called the ureter (say: yu-ree-ter) and collects in the bladder, a storage sac that holds the urine.

• When the bladder is about halfway full, your body tells you to go to the bathroom. When you pee, the urine goes from the bladder down another tube called the urethra (say: yu-ree-thruh) and out of your body.

The Urinary SystemThe Urinary System• the kidneys: filters that take the

waste out of the blood and make urine

• the ureters: tubes that carry the urine to the bladder

• the bladder: a bag that collects the urine

• the urethra: a tube that carries the urine out of the body

LiverLiver• The liver acts as a filter for the blood.

It cleans out toxic waste, poisons, and acid in the blood.

SkinSkin• The skin plays a

major role in excretion. It helps the body get rid of excess water, salts, and waste such as urea. The urea is a nitrogen waste that is filtered out of the blood

LungsLungs

• We may not be aware of it, but our lungs also undergo excretion.

• When our cells convert oxygen into energy, they return carbon dioxide.

• This carbon dioxide has to be removed if not we might die. Thus, our lungs play an important role of removing carbon dioxide from our body.