What hormone, produced by the adrenal medulla in response to acute physical threat or emotional stress, prepares the body for the 'fight-or-flight' response by elevating heart rate, dilating bronchioles, and mobilizing blood glucose?
Answer and explanation
Correct answer: D. Epinephrine (Adrenaline)
- Step 1: The adrenal glands, perched atop both kidneys, are divided anatomically and functionally into an outer cortex and an inner medulla.
- Step 2: In response to sympathetic preganglionic stimulation, chromaffin cells in the adrenal medulla rapidly release epinephrine into the bloodstream, triggering rapid tachycardia, bronchodilation, pupil dilation, and glycogenolysis.
Answer
Epinephrine (Adrenaline)
Why not the others: 'Melatonin' Melatonin is synthesized by the pineal gland to regulate sleep onset and circadian rhythms; 'Insulin' Insulin lowers blood glucose by promoting cellular absorption and storage, opposite to the stress response; 'Prolactin' Prolactin is a pituitary hormone that stimulates milk production in mammary glands.
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