There are numerous possible causes for hard lumps that form under the skin. Lipoma: This is one of the most common types of lumps found under the skin. Lipomas are small, fatty masses that are harmless to your health. Your lump may be a lipoma if it feels soft and rolls easily under your skin.
Good bladder control means you only urinate when. you want to. Most of the bladder control system lies inside the. pelvis. Muscles in the floor of the pelvis need to be. strong and tight to hold up the bladder, a muscular, balloon-shaped sac that stores urine and eliminates. it from the body. Urine exits the bladder and. body through a tube called the urethra. Muscles. surrounding the urethra, called sphincter muscles, squeeze tight to keep it closed. Some of these. muscles are voluntary muscles and are under your. control.
The filtrate, only now called urine, is produced continually by each kidney and drips into the bladder for storage. The bladder is an expandable bag, and when it is full, stretch receptors in the elastic walls send impulses to the medulla, which causes the sphincter muscles to relax, causing urination.