a. Describe how heart contraction and relaxation influence coronary blood flow. b. Name the major branches of the coronary arteries, and note the heart regions served by each.

Video transcript

Hi, everybody. Welcome back. Let's look at our next question, which coronary artery is often referred to as the widow maker due to its critical role in supplying blood to a large portion of the heart. A right coronary artery, B, circumplex artery, C, left interior descending artery and D left marginal artery. Well, the artery we're looking for here is choice C the left, an interior descending artery or L AD. And this does indeed have a critical role in supplying blood to a large portion of the heart. It supplies oxygenated blood to the front and left sides of the heart. And of course, we know what does that include? The left ventricle? I wrote L V which is where blood gets pumped out into the body. So anything that might cause a cut off of oxygenated blood to the left ventricle and therefore causing damage to that muscle can have catastrophic consequences. And a blockage in this left, an interior descending artery can definitely lead to fatal heart attacks. Thus, that nickname of the widow maker, and in fact, this particular artery supply is 50% of the blood supply to the heart muscle. So you can see, this is a pretty key and crucial artery. When we look at our other answer, choices, they all do actually provide some blood supply to parts of the left ventricle, but none of them has as big of a role and supplies as much blood as that left an interior descending artery. So that's why A B and D are incorrect. The A choice A, the right coronary artery supplies blood to the right artery. But R A right ventricle and the bottom of the left ventricle. Choice B, the circumplex artery supplies blood to the left atrium and the lateral wall of the left ventricle. And then choice D the left marginal artery supplies blood to the lateral wall of the left ventricle. So they do each play a play a part in supplying blood to the left ventricle. But again, not as much as this major source. Choice C the left anterior descending artery. See you in the next video.