1. Role of Adrenal Gland in Stress Response:

• The adrenal gland plays a key role in maintaining homeostasis during stress response.
• It synthesizes and releases catecholamines, glucocorticoids, and factors of the renin-angiotensin-aldosterone system.

1. History of Corticosteroids in Inflammatory Diseases:

• Corticosteroids were first used in the treatment of rheumatoid arthritis and gained a reputation in treating inflammatory and autoimmune disorders.
• However, their efficacy comes with potentially serious adverse effects.

1. Anatomy of the Adrenal Gland:

• The adrenal gland is located near the top of each kidney and has a triangular/pyramid-like shape.
• It receives blood supply from various arterial branches and is divided into three layers: zona glomerulosa, zona fasciculata, and zona reticularis.

1. Physiology of the Hypothalamic-Pituitary-Adrenal Axis:

• The HPA axis is a complex system that produces hormones to maintain physiologic integrity during the stress response.
• It involves the hypothalamus, pituitary gland, and adrenal glands, and their hormones regulate the production of corticosteroids.

1. Regulation of ACTH and Cortisol Release:

• ACTH, released by the anterior pituitary gland, stimulates the synthesis and release of corticosteroids from the adrenal glands.
• ACTH release is inhibited by corticosteroids in a feedback loop.

1. Role of HPA Axis in Infections and Immunologic Disorders:

• The HPA axis plays an important role in the stress response to infections and immunologic disorders.
• Stimulation of the immune system leads to the release of proinflammatory cytokines, which in turn stimulate the HPA axis.

1. Adrenal Cortisol Synthesis and Stress Response:

• Adrenal cortisol synthesis in critically ill patients is not regulated by ACTH, but by paracrine pathways via endothelin, atrial natriuretic peptide, or cytokines.