1 A blood clot that forms inside one of your veins or arteries is called a thrombus. A thrombus may also form in your heart.  A thrombus that breaks loose and travels from one location in the body to another is called an embolus.
The kidneys. The kidneys do vital work in the body filtering blood removing waste into urine, and balancing electrolyte levels. Our blood in our bodies passes through the kidneys several times a day. The kidneys are located at the back of the abdomen. Each kidney is about the size of a fist - 10-12.5cm long.
You have two kidneys. They are bean-shaped, and about the size of a fist. They are located in the middle of your back, on the left and right sides of your spine, just below your rib cage. Their main job is to filter extra water and wastes out of your blood and make urine.