The 'mass discharge' of the sympathetic nervous system during intense stress ('fight-or-flight') produces a coordinated physiological response. Which combination of responses correctly represents the integrated sympathetic activation?

• A Increased heart rate, vasodilation in skeletal muscle and skin, bronchoconstriction, pupillary miosis, increased gut motility
• B Increased heart rate and contractility, vasodilation in skeletal muscle (beta-2), vasoconstriction in skin/gut/kidney (alpha-1), bronchodilation (beta-2), pupillary mydriasis, glycogenolysis, reduced insulin secretion ✓
• C Decreased heart rate via baroreceptor activation, bronchodilation, pupillary mydriasis only
• D Sweating suppression, salivary gland hyposecretion with dry thick saliva, increased micturition frequency

Explanation

Mass sympathetic discharge produces: cardiac stimulation (beta-1: increased HR and contractility), skeletal muscle vasodilation (epinephrine acting on beta-2 receptors), vasoconstriction in skin, renal, and splanchnic beds (alpha-1), bronchodilation (beta-2, facilitating O2 uptake), pupillary dilation via iris dilator muscle (alpha-1), glycogenolysis (beta-2 in liver/muscle), reduced insulin secretion (alpha-2 on beta cells), and sweating (cholinergic sympathetic to eccrine glands). Gut motility decreases (alpha-2 reduces ACh release; beta-2 relaxes smooth muscle). Micturition is inhibited (beta-3 relaxes detrusor; alpha contracts internal sphincter). This is the integrated 'fight-or-flight' response preparing the organism for physical activity.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

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