Most forms of life that live on land require mechanisms to conserve water. As land mammals, humans have evolved various ways to maintain proper water levels in the blood. The human body uses a hormone called ADH to help increase the water content of its blood. Low water levels in the blood, which can be caused by dehydration, can cause low blood pressure and high salt levels in the blood. A structure in the brain called the hypothalamus recognizes low blood pressure and high salt levels. This causes the hypothalamus to trigger another brain structure called the pituitary gland to release the hormone Antidiuretic Hormone, or ADH. ADH then travels via the blood throughout the body. In the kidney, cells react to ADH, causing the kidney to retain more water. This results in very concentrated urine.

Question

Based on this passage, identify the systems that are directly involved in increasing water in the blood in response to dehydration.

(1 point)
Responses

nervous, endocrine, digestive, and excretory
nervous, endocrine, digestive, and excretory

nervous, endocrine, circulatory, and excretory
nervous, endocrine, circulatory, and excretory

endocrine, excretory, circulatory, and respiratory
endocrine, excretory, circulatory, and respiratory

nervous, excretory, circulatory, and muscular

Answer 1

Based on the passage, the systems that are directly involved in increasing water in the blood in response to dehydration are the nervous, endocrine, circulatory, and excretory systems.

• The nervous system is involved because the hypothalamus detects low blood pressure and high salt levels.
• The endocrine system is involved because the pituitary gland releases the hormone ADH.
• The circulatory system is involved because ADH travels through the blood to reach the kidneys.
• The excretory system is involved because the kidneys retain more water and produce concentrated urine.

Therefore, the correct response is: nervous, endocrine, circulatory, and excretory.