Biological Systems MCAT Practice Exam

What is the primary function of the adrenal cortex?

1. To release epinephrine

2. To produce steroid hormones

3. To stimulate muscle contraction

4. To regulate blood pressure

The correct answer is: To produce steroid hormones

The primary function of the adrenal cortex is to produce steroid hormones. The adrenal cortex is the outermost layer of the adrenal glands, which are located on top of the kidneys. It synthesizes and secretes various steroid hormones that are crucial for a range of physiological functions. These steroid hormones include corticosteroids such as cortisol, which plays a key role in metabolism and stress response; aldosterone, which is important for regulating sodium and potassium levels thus influencing blood pressure; and androgens, which contribute to the development of male characteristics and reproductive functions. The synthesis of these hormones is essential for maintaining homeostasis in the body, affecting metabolism, immune function, blood pressure regulation, and stress responses. The options related to the release of epinephrine, stimulating muscle contraction, and regulating blood pressure, while related to bodily functions, do not accurately represent the primary role of the adrenal cortex. Epinephrine is produced by the adrenal medulla, not the cortex. Muscle contraction is typically stimulated by neuromuscular signals rather than hormonal action of the adrenal cortex. Although the adrenal cortex does have an influence on blood pressure regulation through aldosterone, its broader and more central function is the production of steroid hormones.