Final answer:
The adrenal medulla produces a secretion that causes fight-or-flight responses in effectors.
Step-by-step explanation:
The gland that produces a secretion causing fight-or-flight responses in effectors is the adrenal medulla. The release of hormones like epinephrine and norepinephrine from the adrenal medulla is stimulated by neural impulses from the sympathetic nervous system, which is activated in response to stress.