GENERAL ANATOMY
CARDIOVASCULAR SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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blood can pass from the atria to the ventricles.
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blood returning from the body can fill theatria.
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the impulse canspread through the Purkinje fibers.
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the SA node can reset and generate anotherimpulse.
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Detailed explanation-1: -The electrical impulse travels from the sinus node to the atrioventricular node (also called AV node). There, impulses are slowed down for a very short period, then continue down the conduction pathway via the bundle of His into the ventricles.
Detailed explanation-2: -In the AV node, the impulses are slowed down for a very short time. This allows the atria to contract a fraction of a second before the ventricles. The blood from the atria empties into the ventricles before the ventricles contract.
Detailed explanation-3: -Good things take time The normal time for an impulse to travel from the SA node, depolarize the atria, and move through the AV node is 0.12 to 0.2 second. You can calculate this by measuring the PR interval. An impulse will normally move through the ventricles in 0.04 to 0.11 second.
Detailed explanation-4: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.