Which part of the adrenal glands is essential for survival?

The cortex of the adrenal glands is essential for survival because it produces hormones that are critical for various bodily functions. The adrenal cortex synthesizes steroid hormones, including glucocorticoids like cortisol, which help regulate metabolism, immune response, and the stress response. It also produces mineralocorticoids, such as aldosterone, which are vital for maintaining fluid and electrolyte balance by regulating sodium and potassium levels in the kidneys. Additionally, androgens produced by the cortex contribute to the development of secondary sexual characteristics and reproductive functions.

The medulla, while important for producing adrenaline and noradrenaline in response to stress, is not as critical for maintaining fundamental physiological functions that sustain life. The capsule is a protective layer surrounding the adrenal gland but does not have a direct role in hormone production or vital functions. The term "adrenaline gland" refers to the adrenal gland's function but does not represent a distinct part of the adrenal glands. Thus, the adrenal cortex is indispensable for survival due to its role in producing hormones that impact essential bodily processes.