What is the Origin of Sympathetic Adrenal Medullary System?

The understanding of this system is a fundamental component of neuroendocrinology, with its function described as part of the autonomic nervous system's stress response model. The term is descriptive, combining the sympathetic branch of the nervous system with the adrenal medulla, the specific endocrine gland involved. Its discovery clarified the rapid, non-steroidal component of the stress reaction.

What is the Mechanism of Sympathetic Adrenal Medullary System?

Activation begins when a stressor is perceived, prompting the hypothalamus to signal the sympathetic nervous system. Preganglionic sympathetic fibers directly innervate the adrenal medulla, bypassing the need for a pituitary hormone. This neural signal causes the chromaffin cells of the medulla to rapidly secrete the catecholamines epinephrine (adrenaline) and norepinephrine (noradrenaline) into the bloodstream. These hormones induce immediate systemic effects, including increased heart rate, elevated blood pressure, and enhanced glucose mobilization.

Sympathetic Adrenal Medullary System ∞ Area

Sympathetic Adrenal Medullary System

Meaning

The Sympathetic Adrenal Medullary (SAM) System is one of the body’s two major neuroendocrine axes responsible for the rapid, acute response to stress, often referred to as the “fight or flight” response. This system involves the direct neural activation of the adrenal medulla to release catecholamines. It is crucial for immediate physiological adaptation to perceived threats or sudden demands.