Final answer:
The kidneys automatically adjust fluid loss through urine in response to water intake. ADH plays a crucial role in signaling the kidneys to conserve or expel water, aiding in maintaining homeostasis.
Step-by-step explanation:
The question asks which sites of fluid loss can be automatically adjusted according to fluid intake volume. The kidneys are the organs responsible for this regulation. When a person experiences dehydration, antidiuretic hormone (ADH) is released by the hypothalamus, which signals the kidneys to conserve water and reduce urine output. Conversely, if there is excess water intake, the kidneys can produce more dilute urine to expel the excess water. This process ensures the balance of water in the body, maintaining homeostasis by adjusting the volume of water lost through the urine.
Moreover, insensible water loss, which includes water lost through the skin (without overt sweating) and respiration, as well as sensible water loss through urine, are part of how the body regulates water levels. The hormonal and neural mechanisms involved, mainly through ADH and the thirst response, aim to preserve blood volume and osmolarity.