BKAT Critical Care Practice Exam

In a state of shock, the activation of the sympathetic nervous system (SNS) leads to several key physiological changes that aim to maintain blood flow to vital organs and correct tissue perfusion. One of the hallmark responses of SNS activation is vasoconstriction, where blood vessels narrow. This response increases systemic vascular resistance, which helps elevate blood pressure, a critical factor when the body is in shock. Alongside vasoconstriction, there is also an increase in heart rate as a compensatory mechanism to maintain cardiac output. The heart pumps faster to circulate blood more effectively despite the reduced blood volume or impaired circulation caused by shock. By raising both heart rate and vascular tone, the body attempts to optimize perfusion to essential organs like the heart and brain during a critical time. These combined effects of vasoconstriction and increased heart rate are fundamental to the body's fight-or-flight response, aiming to restore homeostasis under stressful conditions. Hence, the choice reflecting vasoconstriction and increased heart rate accurately describes the physiological changes expected during shock due to SNS activation.