AP BIOLOGY

Detailed explanation-1: -The main stimulus to the secretion of vasopressin is an increase in osmolality detected by osmoreceptors lying close to the nuclei in the hypothalamus. The osmoreceptors are extremely sensitive to changes in osmolality, a 1% change in osmolality will result in a measurable release of vasopressin.

Detailed explanation-2: -Kidneys regulate the osmotic pressure of a mammal’s blood through extensive filtration and purification, in a process known as osmoregulation. Kidneys filter the blood; urine is the filtrate that eliminates waste from the body via the ureter into the bladder.

Detailed explanation-3: -Osmoregulation is the control of water levels and mineral ions (salt) in the blood. Water levels and mineral ions in the blood are controlled to keep the concentrations the same inside the cells as around them. This protects cells by stopping too much water from entering or leaving them by osmosis.

Detailed explanation-4: -Osmoregulation occurs in the medulla of the kidney and involves two key events: The loop of Henle establishes a salt gradient (hypertonicity) in the medulla. Anti-diuretic hormone (ADH) regulates the level of water reabsorption in the collecting duct.