Which structures quickly distribute impulses through the ventricles to coordinate contraction?

Which structures quickly distribute impulses through the ventricles to coordinate contraction?

• A. Purkinje fibers
• B. Bundle of His
• C. AV node
• D. SA node

Answer: (A)

The main idea is how the heart spreads an electrical impulse quickly to coordinate ventricular squeezing. Purkinje fibers form a specialized, fast-conducting network inside the ventricles that rapidly distributes the impulse to all ventricular myocytes. This rapid spread ensures the ventricles depolarize almost simultaneously, producing a synchronized contraction that efficiently ejects blood. After the impulse starts at the sinoatrial node, it travels to the atrioventricular node, which delays the signal to allow filling. From there it moves through the bundle of His and then into the Purkinje network. The Purkinje fibers conduct the signal much faster than other cardiac tissues, delivering it to both ventricles so they contract together.

The main idea is how the heart spreads an electrical impulse quickly to coordinate ventricular squeezing. Purkinje fibers form a specialized, fast-conducting network inside the ventricles that rapidly distributes the impulse to all ventricular myocytes. This rapid spread ensures the ventricles depolarize almost simultaneously, producing a synchronized contraction that efficiently ejects blood.

After the impulse starts at the sinoatrial node, it travels to the atrioventricular node, which delays the signal to allow filling. From there it moves through the bundle of His and then into the Purkinje network. The Purkinje fibers conduct the signal much faster than other cardiac tissues, delivering it to both ventricles so they contract together.