What is the role of the cardiac center?

What is the role of the cardiac center?

• A. To regulate heart rate and cardiac output based on signals from baroreceptors and chemoreceptors.
• B. To regulate only heart rate independent of receptors.
• C. To regulate vascular resistance exclusively.
• D. To generate action potentials in the AV node.

Answer: (A)

The cardiac center coordinates autonomic control of the heart using feedback from sensors that monitor the body's status. It sits in the medulla and receives input from baroreceptors, which sense arterial pressure, and chemoreceptors, which detect levels of oxygen, carbon dioxide, and pH. Based on this information, it adjusts the balance of sympathetic and parasympathetic output to the heart. When pressure rises, it increases parasympathetic (vagal) activity and dampens sympathetic output, slowing the heart and reducing the strength of contraction, which lowers cardiac output and helps bring blood pressure back toward normal. When pressure falls, sympathetic activity rises, boosting heart rate and contractility to raise cardiac output and pressure. Chemoreceptor signals help tilt this response when metabolic needs change, such as during hypoxia or acidosis. The result is regulation of heart rate and cardiac output in response to these signals; vascular resistance is controlled by other mechanisms, not the cardiac center alone.

The cardiac center coordinates autonomic control of the heart using feedback from sensors that monitor the body's status. It sits in the medulla and receives input from baroreceptors, which sense arterial pressure, and chemoreceptors, which detect levels of oxygen, carbon dioxide, and pH. Based on this information, it adjusts the balance of sympathetic and parasympathetic output to the heart. When pressure rises, it increases parasympathetic (vagal) activity and dampens sympathetic output, slowing the heart and reducing the strength of contraction, which lowers cardiac output and helps bring blood pressure back toward normal. When pressure falls, sympathetic activity rises, boosting heart rate and contractility to raise cardiac output and pressure. Chemoreceptor signals help tilt this response when metabolic needs change, such as during hypoxia or acidosis. The result is regulation of heart rate and cardiac output in response to these signals; vascular resistance is controlled by other mechanisms, not the cardiac center alone.