Increased heart rate and blood pressure.Some notable effects of adrenaline and noradrenaline include: All of these peptides bind to opioid receptors and produce analgesic (and other) responses. The enkephalins and enkephalin-containing peptides are related to, but also distinct from, the endogenous peptides named endorphins (secreted from the pituitary). The secreted adrenaline and noradrenaline play an important role in the fight-or-flight response. When stimulated, chromaffin cells secrete adrenaline and noradrenaline along with enkephalin and enkephalin-containing peptides into the bloodstream. To carry out this response, the adrenal medulla receives input from the sympathetic nervous system through nerve fibers originating in the thoracic spinal cord from T5–T11.Ĭhromaffin cells are the neuroendocrine cells found in the medulla they are modified post-synaptic sympathetic neurons that receive sympathetic input. The adrenal medulla secretes approximately 20% noradrenaline (norepinephrine) and 80% adrenaline (epinephrine). These water-soluble hormones are the major hormones underlying the fight-or-flight response. The adrenal medulla is responsible for the production of catecholamines, derived from the amino acid tyrosine.Īdrenal gland: The adrenal medulla sits below the three layers of the adrenal cortex and is innervated by nerve fibers.

The adrenal medulla is the core of the adrenal glands, and is surrounded by the adrenal cortex. chromaffin: The cells of the adrenal medulla that secrete adrenaline and noradrenaline in response to nervous stimulation.adrenal cortex: The outer portion of the adrenal glands that produces hormones essential to homeostasis.The adrenal cortex is devoted to the synthesis of corticosteroid and androgen hormones.

Adrenal medulla location