Arteries carry oxygenated blood away from the heart to your organs. They have thick walls with muscle tissue and are deep inside your muscles.

In contrast, veins carry deoxygenated blood towards the heart. They have thinner walls, use valves to keep blood flowing, and lie near the body’s surface.

On the other hand, nerves are an axon bundle of neurons. They are part of the peripheral nervous system, delivering nerve impulses and running throughout your body.

Human kidney

The kidneys filter half a cup of blood per minute to remove waste and extra water and create urine. The urine then flows to the bladder through the ureters. The kidneys are located just below the rib cage on both sides of the spine.

Ureter

The ureters, being part of the urinary system, are two tubes that transport urine from each kidney to the bladder. Their walls have three layers: the outer layer (connective tissue), the middle layer (smooth muscle), and the inner layer (transitional epithelium).