adding on to brenna's post

Everyone has blood and you can't expect that your blood to use everything that's in it. Your blood needs to balance the amount of things you need just like a scale. Well when it balances the scale it has to have things leftover. That's where the kidneys come in. The kidneys have 1 million tiny filter called nephrons that are so tiny yo have to look through a really strong microscope to see them. The blood runs through the kidney and the nephrons go to work cleaning the blood. Once the blood is filtered it leaves the kidney and the waste gets mixed with water. The kidneys filter blood 400 times a day! Your kidneys are about the size of a computer mouse!   

Excretory System

Kidneys are bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage. These pictures show how a kidney works and what's inside a kidney. Blood enters the kidney through the renal artery and after its filtered by the kidney the clean blood leaves through the renal vein. Kidneys are pretty amazing filters. Inside the kidney, the filtering is done by tiny things called nephrons. There are about a million nephrons in each kidney. Each kidney can filter about 200 quarts of blood to remove about 2 quarts of waste and extra water every day. The waste and extra water become urine, which flows down to the bladder through tubes called ureters. The bladder stores the urine until it's excreted in the bathroom.

Diagram of the excretory system

This is a picture of the excretory system. The diagram is of all the parts of it. It has the two kidneys that look like beans and then the two tubes going down is the right ureter and the left ureter. Then there's the bladder in which the tubes are going into then there's the tube going down and thats the urethra.   

simple picture of the excretory system

How it works

                                                                    

When you eat something your body takes as much as it needs, then whatever the body doesn't need it sends it to the excretory system. Your body needs to balance the amount of water, food and anything else your body needs or else the excretory system would be almost useless and your body would have to much stuff left over. First your blood goes into your kidneys and the kidneys act like a strainer and takes a substance called urea from the blood as the blood passes through and then the urea/urine goes down a tube called the ureter and the urine goes into your bladder were it stays until the bladder gets emptied and the urine goes down a tube called the urethra and out of your body completely. The bladder doesn't empty right away instead it holds the urine until your ready to go to the bathroom. But your bladder doesn't stay the same size, it swells when it's full and it shrinks when it's emptied. If your bladder emptied every time urine came into it you would have to go to the bathroom a lot.

The Human Excretory System Diagram

Illustrations and references

The Human Excretory System

The word excretion means to remove. The human excretory system removes waste from the body. Many organs are part of the excretory system, including the kidneys, sweat glands, lungs and rectum. The primary organs that remove waste are the kidneys. Excretion is vital to human health because waste is poison. If waste builds up and is not removed, it can cause serious problems. Carbon dioxide and water vapor are removed by the lungs. Other waste, like urea, uric acid, salts and other waste, is removed by the kidneys and sweat glands.