Question

Which of the following is true of the adrenal glands? a. They produce insulin. b. They produce hormones that control ion balance and maintain glucose homeostasis. c. They produce only steroid hormones. d. They are inhibited by the pituitary hormone ACTH. e. They chiefly regulate \(\mathrm{Ca}^{2+}\) balance.

Short answer

The correct answer is option B: The adrenal glands produce hormones that control ion balance and maintain glucose homeostasis.

Step-by-step solution

Analyze Option A

The adrenal glands do not produce insulin. Insulin is a hormone that is produced in the pancreas, not in the adrenal glands.

Analyze Option B

The adrenal glands do indeed produce hormones that help maintain both ion balance and glucose homeostasis in the body. Namely, these hormones are aldosterone which regulates ion balance by helping maintain blood pressure and body salt and water levels, and cortisol which is involved in glucose metabolism.

Analyze Option C

The adrenal glands produce both steroid and non-steroid hormones. The cortex of the adrenal gland produces steroid hormones and the medulla produces hormones such as epinephrine and norepinephrine, which are not steroids.

Analyze Option D

The adrenal glands are not inhibited by the pituitary hormone ACTH (adrenocorticotropic hormone). In fact, ACTH stimulates the adrenal glands to release cortisol.

Analyze Option E

The adrenal glands do not chiefly regulate \(\mathrm{Ca}^{2+}\) balance. Parathyroid hormone, which is released by the parathyroid glands, is predominantly responsible for \(\mathrm{Ca}^{2+}\) balance in the body.

Key concepts

Hormone Production

Understanding how our bodies function can be quite the challenge, yet starting with the basics can make a significant difference. One such basic is the hormone production in our adrenal glands; these are small organs perched atop each kidney. They consist of two main parts: the adrenal cortex and the adrenal medulla, each producing different sets of hormones.

The adrenal cortex focuses primarily on steroid hormones such as cortisol, aldosterone, and androgens. Cortisol is known as the stress hormone, aiding in the regulation of metabolism and helping the body respond to stress. Aldosterone plays a key role in controlling blood pressure by managing sodium and potassium levels, while androgens are small quantities of male sex hormones. Conversely, the adrenal medulla produces non-steroidal hormones like epinephrine and norepinephrine (also known as adrenaline and noradrenaline). These are responsible for the body's fight-or-flight response, rapidly preparing the body to react to stressful situations.

Unlike insulin, which is a key player in controlling glucose levels and is produced by the pancreas, these hormones coordinate a wide variety of vital functions, ensuring our bodies respond appropriately to different changes in our environment or internal conditions.

Glucose Homeostasis

Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. A vital aspect of homeostasis is the regulation of blood glucose levels. This process, known as glucose homeostasis, is partly managed by the hormone cortisol, produced by the adrenal glands.

Cortisol works by increasing the amount of glucose in the blood, making it an essential component for proper metabolic function. It does this by stimulating gluconeogenesis, which is the production of glucose from non-carbohydrate sources in the liver, and by mobilizing amino acids and fatty acids. Furthermore, cortisol helps to temper the effect of insulin, ensuring that not all glucose is ushered into the cells, thereby keeping a portion in the bloodstream for use where needed.

This orchestrated effort helps to ensure that cells throughout the body have a steady supply of energy, especially during periods of fasting or intense physical activity. Understanding this process is not just about diving into biochemistry; it's about appreciating how our body maintains balance and supplies our organs, including the brain, with energy to perform optimally.

Ion Balance

Balance is not only a concept that applies to our daily lives but also a critical aspect of our bodily functions, such as the ion balance, primarily maintained through the hormone aldosterone, one of the adrenal glands' essential outputs.

Aldosterone is part of the renin-angiotensin-aldosterone system, which regulates blood pressure and fluid balance by controlling how much sodium and potassium the body retains or excretes. When aldosterone signals the kidneys to retain sodium, water retention will also increase, leading to an elevation in blood volume and blood pressure. Conversely, it causes the excretion of potassium, maintaining the delicate balance of these electrolytes which is vital for functions such as muscle contraction and nerve signaling.

Maintaining this ion balance is a fine act, with repercussions for cardiovascular health and overall well-being. Issues with the adrenal glands can cause a cascade of problems, highlighting the importance of these small but mighty organs in our endocrine system.