Problem 29 - Objective Biology for NEET

Question

Which of the following hormone stimulates the synthesis and secretion of steroid hormones called glucocorticoids from the adrenal cortex? (a) TSH (b) ACTH (c) \(\mathrm{LH}\) (d) \(\mathrm{FSH}\)

Step-by-Step Solution

Answer

The hormone that stimulates the synthesis and secretion of glucocorticoids from the adrenal cortex is ACTH.

Step 1: Analyzing the Hormones

In this list of hormones, TSH is thyroid stimulating hormone produced by the pituitary gland and regulates the thyroid. ACTH stands for Adrenocorticotropic hormone also from the pituitary gland and it regulates the adrenal cortex. LH is Luteinizing hormone which primarily serves to regulate the reproductive system. FSH is follicle stimulating hormone, also mostly targeting the reproductive system.

Step 2: Identifying the Right Hormone

From the definitions of the functions of these hormones, it's clear that the Adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex which then produces glucocorticoids.

Key Concepts

Hormone Function

Hormones are vital chemical messengers in the body. They are produced by various glands and play crucial roles in regulating bodily functions. These molecules travel through the bloodstream to tissues and organs, affecting many physiological activities such as growth, metabolism, mood, immune function, and reproduction.

Some hormones work quickly to start or stop a process, while others continuously regulate processes to maintain balance in the body. Hormones are specific, which means they target particular cells or organs, and their effects can be widespread, affecting various parts of the body simultaneously. Understanding each hormone and its specific function is essential to comprehend how the endocrine system maintains the body's homeostasis.

Adrenocorticotropic Hormone (ACTH)

The Adrenocorticotropic Hormone (ACTH) is a crucial component in the endocrine system. It is produced by the anterior pituitary gland, a small, pea-sized gland located at the base of the brain. ACTH's primary role is to signal the adrenal glands to release certain hormones.

ACTH specifically stimulates the adrenal cortex, which is a part of the adrenal glands, to produce steroid hormones known as glucocorticoids. The release of ACTH is controlled by the hypothalamus through the corticotropin-releasing hormone (CRH). ACTH secretion is influenced by the body's circadian rhythm, as well as by stress. High levels of ACTH will lead to increased production of glucocorticoids, which help the body manage stress and maintain essential bodily functions.

Glucocorticoids

Glucocorticoids are a category of steroid hormones that play a significant role in the body's ability to handle stress and inflammation. The most well-known glucocorticoid is cortisol. These hormones are produced in the adrenal cortex and are integral to various bodily functions.

Key roles of glucocorticoids include:

• Regulating metabolism by increasing blood glucose through gluconeogenesis.
• Suppressing inflammatory and immune responses, preventing over-reactions of the immune system.
• Assisting in stress response by preparing the body to handle stress effectively.

Overall, glucocorticoids are essential in maintaining energy balance and homeostasis, especially during stress.

Adrenal Cortex

The adrenal cortex is the outer region of the adrenal glands, which sit atop each kidney. It is responsible for producing several critical hormones, including glucocorticoids, mineralocorticoids, and androgens. This part of the adrenal gland is essential for various bodily processes.

Functions of the adrenal cortex include:

• Producing glucocorticoids to manage stress and metabolism.
• Secreting mineralocorticoids, such as aldosterone, which help regulate blood pressure and electrolyte balance.
• Releasing androgens, which are involved in the development of secondary sexual characteristics.

The adrenal cortex is activated by ACTH from the pituitary gland, ensuring that the body can react optimally to stress and maintain overall health and well-being.