Biology 30 – Nervous and Endocrine System Practice Test 2026 - Free Practice Questions and Study Guide

When the body is under stress, it needs quick energy, so a hormone called cortisol from the adrenal cortex rises to meet that demand. Cortisol acts to increase blood glucose by promoting gluconeogenesis in the liver, breaking down proteins in muscle to supply amino acids for glucose production, and limiting glucose uptake by some tissues to spare glucose for the brain. Among the options, cortisol is the specific hormone responsible for this glucose-raising stress response. Aldosterone mainly regulates salt and water balance, not glucose. The term glucocorticoid refers to a class that includes cortisol, but the one most closely tied to raising blood sugar in stress is cortisol. Thyroxine comes from the thyroid and primarily affects overall metabolic rate, not the acute stress-induced glucose surge.