Features of neurogenic shock are –
**Core Concept**
Neurogenic shock is a type of shock that occurs due to the disruption of sympathetic nervous system control, leading to unopposed parasympathetic activity. This results in vasodilation, venodilation, and a subsequent decrease in peripheral resistance and cardiac output.
**Why the Correct Answer is Right**
In neurogenic shock, there is an unopposed effect of acetylcholine (ACh) on the parasympathetic receptors, causing vasodilation and venodilation. The vasodilation leads to a decrease in peripheral resistance, while the venodilation results in a decrease in venous return. The combination of decreased peripheral resistance and decreased venous return ultimately leads to a decrease in cardiac output. This is because the heart receives less blood to pump, and the vessels offer less resistance for the heart to pump against.
**Why Each Wrong Option is Incorrect**
**Option A:** The statement that peripheral resistance increases is incorrect because neurogenic shock is characterized by vasodilation and decreased peripheral resistance.
**Option B:** The statement that venous return decreases is correct, but the combination of decreased venous return and decreased peripheral resistance is what leads to decreased cardiac output.
**Option D:** Venoconstriction is incorrect because neurogenic shock is characterized by venodilation, not venoconstriction.
**Clinical Pearl / High-Yield Fact**
In neurogenic shock, the classic presentation is hypotension, bradycardia, and warm, well-perfused skin due to vasodilation.
**✓ Correct Answer: C. |Peripheral resistence | cardiac output**