What is the primary function of the adrenal glands?

The primary function of the adrenal glands is the regulation of metabolism, immune response, and stress responses. Located on top of each kidney, the adrenal glands consist of two main parts: the adrenal cortex and the adrenal medulla. The adrenal cortex produces hormones like cortisol, which plays a critical role in metabolism by increasing blood sugar through gluconeogenesis, and aldosterone, which helps regulate blood pressure and electrolyte balance. In times of stress, the adrenal medulla releases adrenaline (epinephrine) and noradrenaline (norepinephrine), which prepare the body for a "fight or flight" response, significantly influencing heart rate, blood pressure, and energy levels.

The other options do not accurately reflect the primary functions of the adrenal glands. The production of digestive enzymes is primarily a function of the pancreas, while the secretion of neurotransmitters is related to the nervous system and occurs primarily in neurons. The absorption of nutrients is managed by the gastrointestinal tract, not the adrenal glands. Thus, choice B accurately encapsulates the comprehensive roles that the adrenal glands play in maintaining homeostasis and responding to various physiological stressors.