A blood calcium level that is too HIGH, and is associated with a HIGH parathyroid hormone level MUST be due to a tumor in the parathyroid gland. That is, the high blood calcium is a result of the excess parathyroid hormone (PTH). It is the parathyroid gland that is the problem.
Urethral sphincters. The urethral sphincters are two muscles used to control the exit of urine in the urinary bladder through the urethra. The two muscles are either the male or female external urethral sphincter and the internal urethral sphincter. When either of these muscles contracts, the urethra is sealed shut.
1 Urine is stored in the bladder. 2  The sphincter muscles relax. 3  The bladder muscle (detrusor) contracts. 4  The bladder is emptied through the urethra and urine is removed from the body. The primary receptors in the bladder neck are alpha-adrenergic. 2  Sympathetic stimulation of these alpha receptors, via fibers in the hypogastric nerve, contributes to urinary continence. 3  The external sphincter is histologically different from the detrusor and internal sphincter. 4  It is striated muscle.