In the heart, which of the following apply? (1) Action potentials are conducted from cell to cell across the myocardium via gap junctions, (2) the SA node sets the pace for the heart as a whole, (3) spontaneous depolarization of cardiac cells can occur in the absence of nerve stimulation, (4) cardiac muscle can continue to contract for long periods in the absence of oxygen. a. all of the above, b. 1, 3, 4, c. 1, 2, 3, d. 2, 3.

Video transcript

Hi, everybody. Let's look at our next question. After passing through the A V node, the electrical impulses travel along the choice. A bundle of hiss BS A node, C Perini fibers or D atria. So to think this through, we'll just look at a little rough diagram of the heart here. And I've actually heart shaped, but mainly I just want to keep track of our quadrants here. So we've got our right atrium top left as we're looking at it right ventricle below it left atrium on the top right of the diagram and left ventricle. When we think about how the electral impulses travel through the heart, they're going to start in the essay node up in the right atrium. And from there, the electral impulse travels to that A V node and A V node is of course given by its name in between the atria and the ventricles from the A V node. The electrical signal goes to the bundle of hiss between the two ventricles from there. It then travels separately to either side along the right and left bundle branches. And then last of all into the Perini fibers which travel up into the ventricles or cause the electrical signals to travel up into the ventricles. So we've got our bundle branches below our bundle of his and then the Perini fibers as the final step for those electral impulses to travel up to the ventricles. So, with that in mind, we're looking back at our problem, which is where does the electrical impulse travel after it passes through the A V node? And the answer would be choice A, the bundle of hiss. When we look at our other answer, choices, choice B the S A node is where those electoral impulses start. So then they go from there to the A B node. So that's not a correct answer. And then choice C the buri fibers is the end that final destination of the electrical impulse. So not correct. And then finally choice D the atria uh the electrical impulses start here since the essay note is in the right atrium. So as they start in the right atrium, but it's not where it travels. After the A V node, it's going to travel through those various fibers and then go into the ventricles. So is not correct. So again, after they travel through the A B node, electro impulses travel along me. Choice a bundle of hiss. See you in the next video.