Final answer:
Drinking 16 oz of salt water would increase blood osmolarity, leading to secretion of ADH and aldosterone, reducing urine volume, and increasing urine solute concentration to maintain fluid homeostasis.
Step-by-step explanation:
Effects of Drinking Salt Water on Osmoregulation
If a physiology student drank 16 oz of salt water, their blood osmolarity would likely increase due to the high sodium content in salt water. This elevated blood osmolarity would trigger osmoreceptors in the hypothalamus, resulting in the secretion of antidiuretic hormone (ADH) from the posterior pituitary gland. ADH functions to make the kidneys more permeable to water by inserting water channels, aquaporins, into the kidney tubules, thus encouraging water reabsorption and reducing urine volume. Concurrently, aldosterone would likely be stimulated to increase sodium reabsorption and further assist in water retention. Consequently, this would lead to a decrease in urine volume and an increase in urine solute concentration.
The relationship between urine volume, solute concentration, and the hormones ADH and aldosterone is instrumental in maintaining body fluid homeostasis. Elevated ADH levels reduce urine output and increase its concentration, whereas aldosterone aids by promoting sodium (and indirectly water) retention. Together, they work to correct the hyperosmotic state caused by ingesting salt water.
In summary, due to the presence of excess solutes from the salt water, the body would engage hormonal mechanisms that prioritize water conservation, thereby minimizing the impact of increased salt intake on overall fluid balance and blood pressure.