Drinking plenty of water will increase the secretion of antidiuretic hormone. Wrong, the main function of antidiuretic hormone is to improve the permeability of distal convoluted tubules and collecting ducts to water and promote water absorption. It is the key hormone to regulate the concentration and dilution of urine, that is, to reduce urination. After drinking a lot of water, urination will increase, so the secretion of antidiuretic hormone will decrease.
B the secretion of antidiuretic hormone decreases and the urine output increases, which is correct. The reason depends on the role of antidiuretic hormone in the explanation of option A.
The thirst center is excited and the antidiuretic hormone is reduced. Wrong, antidiuretic hormone is a 9-peptide hormone secreted by nerve cells in supraoptic nucleus and paraventricular nucleus of hypothalamus, which is released after reaching the posterior lobe of neurohypophysis through hypothalamic-pituitary bundle. The thirst center is in the cerebral cortex, which makes people feel thirsty and only regulates people's drinking water.
D the osmotic pressure of extracellular fluid increased and the urine volume increased. Wrong, extracellular fluid is mainly tissue fluid and lymph, and some is blood. The increase of osmotic pressure will lead to dehydration of cells, dehydration of human body and decrease of urine volume.