Volcanoes produce a wide variety of natural hazards that can kill people and destroy property. This simplified sketch shows a volcano typical of those found in the Western United States and Alaska, but many of these hazards also pose risks at other volcanoes, such as those in Hawaii. Some hazards, such as lahars and landslides, can occur even when a volcano is not erupting.
A sphincter is a ring of muscle which holds any kind of biological opening closed. Sphincters are an important part of almost any system in a body. They help to both regulate the exit, entrance and circulation of fluids, gasses, and solids.
the bladder sphincter is a muscular valve that lies at the bottom of the bladder it works to control the flow of urine in pregnancy the expanding uterus puts pressure on the bladder the muscles in the bladder sphincter and in the pelvic floor can be overwhelmed by the extra stress or pressure on the bladder urine may leak out of the bladder when there is additional pressure exerted for example when a pregnant woman coughs or sneezes