1 Excretion-Wastes such as excess water, salt, urea and uric acid are removed from the body in sweat. 2  Waterproofing-The skin with its oil glands prevents the entry of water into, and loss of water out of the body. 3  Protection from Disease-The intact skin prevents invasion of micro-organisms and dust into the body.ubes called ureters carry waste products from the kidneys to the urinary bladder for storage or for release. Details of the human excretory system. Position and allied structures of the kidneys (top). A cross section of the kidney showing the two major portions (left).
Each leg has a long sciatic nerve that runs through the buttock, down the back of the thigh, and into the foot and toes. Sciatica is pain felt along the course of those nerves and their branches, so while the problem originates in the lower lumbar region of the spine, the symptoms are felt mainly in the legs. Many people with the condition have a history of back problems, but sciatica often starts suddenly. It can be triggered by something minor â even a sneeze.
Sciatica most commonly occurs when a herniated disk, bone spur on the spine or narrowing of the spine (spinal stenosis) compresses part of the nerve. This causes inflammation, pain and often some numbness in the affected leg. Although the pain associated with sciatica can be severe, most cases resolve with non-operative treatments in a few weeks. People who have severe sciatica that's associated with significant leg weakness or bowel or bladder changes might be candidates for surgery.