Question

Which of the following statements about the adrenal cortex or its hormones is true? a. The adrenal cortex secretes a mixture of steroid and nonsteroid hormones. b. The adrenal cortex secretes hormones that may decrease the inflammatory response and suppress immune responses. c. The secretion of hormones by the adrenal cortex is controlled by the sympathetic division of the nervous system. d. Hypersecretion of cortisol and aldosterone is seen in Addison's disease.

Short answer

b. The adrenal cortex secretes hormones that may decrease the inflammatory response and suppress immune responses.

Step-by-step solution

Identify Hormones Secreted by Adrenal Cortex

The adrenal cortex primarily secretes steroid hormones, such as cortisol, aldosterone, and androgens. This eliminates option a.

Understand Function of Adrenal Cortex Hormones

Cortisol has anti-inflammatory effects and can suppress the immune response. Therefore, option b seems to be true.

Determine Control Mechanism for Hormone Secretion

The adrenal cortex is mainly controlled by the pituitary gland via ACTH (adrenocorticotropic hormone), not by the sympathetic nervous system. This eliminates option c.

Connection to Diseases

Addison’s disease is characterized by the underproduction (hyposecretion) of cortisol and aldosterone, opposing hypersecretion. This eliminates option d.

Key concepts

steroid hormones

Steroid hormones are a group of hormones produced mainly by the adrenal cortex, gonads, and placenta. They are derived from cholesterol, which is converted through a series of biochemical processes.

Steroid hormones include:

• Glucocorticoids (e.g., cortisol)
• Mineralocorticoids (e.g., aldosterone)
• Androgens (e.g., testosterone)
• Estrogens and progestogens

The adrenal cortex specifically secretes glucocorticoids, mineralocorticoids, and a small amount of androgens. These hormones play crucial roles in various physiological processes.

For example, cortisol helps regulate metabolism and immune response, aldosterone manages sodium and potassium levels, and androgens influence sexual development and reproduction. Steroid hormones are fat-soluble, allowing them to pass through cell membranes and bind to specific receptors inside target cells.

The synthesis and release of steroid hormones are tightly regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Understanding the functions and regulation of these hormones is essential for comprehending various aspects of endocrinology and their impact on health.

cortisol

Cortisol is one of the primary steroid hormones produced by the adrenal cortex. It is often referred to as the 'stress hormone' because it is released in response to stress and low blood-glucose concentration. Here are some key functions of cortisol:

• Regulating blood sugar levels by increasing gluconeogenesis
• Suppressing the immune system to reduce inflammation
• Helping in the metabolism of fat, protein, and carbohydrates
• Controlling the body's salt and water balance
• Influencing memory formation and maintaining homeostasis during stress

When released into the bloodstream, cortisol binds to glucocorticoid receptors in various tissues. This binding triggers a wide array of physiological reactions aimed at restoring homeostasis.

Prolonged high levels of cortisol can lead to several health issues, including weakened immune function, hypertension, high blood sugar, and even osteoporosis. It's essential to maintain cortisol levels in a balanced range for optimal bodily function.

Cortisol secretion follows a diurnal rhythm, peaking in the early morning and gradually decreasing throughout the day. This rhythm can be interrupted by factors like stress, illness, or irregular sleep patterns.

ACTH

Adrenocorticotropic hormone (ACTH) is a crucial peptide hormone produced by the anterior pituitary gland. It plays an essential role in regulating the secretion of cortisol from the adrenal cortex.

Here are some important aspects of ACTH:

• ACTH is part of the hypothalamic-pituitary-adrenal (HPA) axis.
• Its release is stimulated by corticotropin-releasing hormone (CRH) from the hypothalamus.
• ACTH acts on the adrenal cortex to promote the synthesis and release of cortisol.
• It follows a diurnal rhythm, similar to cortisol, with levels peaking in the morning.

When the body experiences stress, the hypothalamus secretes CRH, which then stimulates the pituitary gland to release ACTH. ACTH travels through the bloodstream to the adrenal cortex, triggering the release of cortisol, which helps the body respond to stress.

Normal functioning of the HPA axis is vital for maintaining homeostasis. Dysregulation can lead to disorders such as Cushing's syndrome (excessive cortisol production) or Addison's disease (insufficient cortisol production).

Understanding how ACTH functions and influences the adrenal cortex can provide insights into various endocrine disorders and stress-related conditions.