The largest oil spill to occur in the United States so far was the Exxon Valdez spill into Prince William Sound, Alaska, in March 1989. The Exxon Valdez, a medium-sized oil tanker, ran aground on a reef to cause this spill of almost 11 million gallons of crude oil.
Sphincters, composed of skeletal muscles, regulate movement through our digestive and urinary systems, thus, controlling swallowing, defecation and even urination. Skeletal muscle contraction generates heat, which helps to maintain body temperature.
The urethral sphincter is one of two muscles used to control the exit of urine in the urinary bladder through the urethra. The two muscles are the male or female external urethral sphincter and the internal urethral sphincter.When either of these muscles contracts, the urethra is sealed shut.The external urethral sphincter originates at the ischiopubic ramus and inserts into the intermeshing muscle fibers from the other side.It is controlled by the deep perineal branch of the pudendal nerve.hen either of these muscles contracts, the urethra is sealed shut. The external urethral sphincter originates at the ischiopubic ramus and inserts into the intermeshing muscle fibers from the other side. It is controlled by the deep perineal branch of the pudendal nerve.