Tumor markers are substances that may be detected in cells or body fluids and can provide clues to the presence, extent, and treatment response of certain neoplasms. What is an example of a tumor marker?

Choice A reason: Micturition, or urination, is stimulated by the filling of the bladder. As the bladder fills with urine, stretch receptors in the bladder wall are activated. These receptors send signals to the brain, which then triggers the urge to urinate. When the bladder is full enough, the brain sends signals to the muscles of the bladder to contract and to the urethral sphincter to relax, allowing urine to be expelled from the body.

Choice B reason: Segmental movement refers to the rhythmic contractions and relaxations of segments of the intestine that help in the movement of contents along the gastrointestinal tract. It is not related to the process of micturition.

Choice C reason: Rectal filling is associated with the defecation reflex, not micturition. When the rectum fills with feces, stretch receptors in the rectal walls are activated, leading to the urge to defecate. This process is separate from the mechanisms involved in urination.

Choice D reason: Mass movements are large, strong contractions of the colon that move fecal matter toward the rectum, facilitating defecation. They are not involved in the process of micturition.

Choice A reason: Excessive fluid replacement can lead to hypervolemia because it increases the total volume of fluid in the body. This can overwhelm the body's regulatory mechanisms, leading to fluid overload.

Choice B reason: Dehydration is not a cause of hypervolemia. In fact, dehydration is the opposite condition, where there is a lack of fluid in the body. Dehydration leads to a decrease in fluid volume, not an increase.

Choice C reason: Liver cirrhosis can cause hypervolemia because it impairs the liver's ability to regulate fluid balance. This can result in fluid retention and buildup in the body, leading to hypervolemia.

Choice D reason: Kidney failure can cause hypervolemia because the kidneys are responsible for maintaining fluid balance by excreting excess fluid. When the kidneys fail, they cannot effectively remove excess fluid, leading to fluid overload.