Inferior Mesenteric Artery – Arterial Supply to the GI Tract

by James Pickering, PhD

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    00:01 The inferior mesenteric artery, this is the third unpaired artery.

    00:06 This coming off the aorta, the unpaired visceral branch, this coming up from the aorta.

    00:11 Comes away at about L3, inferior mesenteric artery. Comes away L3 and it supplies the distal 1/3rd of the transverse colon, the distal 1/3rd of the transverse colon.

    00:25 descending colon, sigmoid colon and parts of the rectum.

    00:30 It does this by the left colic, which we can see passing towards the left, towards the descending colon.

    00:36 It also gives rise to a series may be three four sigmoidal arteries which go to supply the sigmoidal colon.

    00:45 And then it gives rise to a superior rectal artery. And this will be the one that most continuous with the inferior mesenteric artery. As the inferior mesenteric artery comes down the initial left artery gives off to be the left colic. The subsequent left artery would be the sigmoidal artery.

    01:02 And the remaining one, would be your superior rectal which we can see here. These were your sigmoidal let me call your left colic And what we can see is the left colic and also to some extent the sigmoidal artery are running towards the colon where they meet essentially what is this quite large arcade similar to what we had with the small intestine.

    01:25 And that arcade is being fed into via left colic and the middle colic coming from the superior mesenteric artery. So this stretch here is known as the marginal artery. A stretch of arterial blood is running parallel along the inside of the colon And that helps to supply this transitional area between the midgut and the hindgut.

    01:53 Just before the bifurcation of the aorta into common iliacs, just superior to that you have L3 where the inferior mesenteric arteries occurring.

    02:04 And at this location, it's quite common for the atherosclerotic plaques to occur.

    02:09 And this can actually occlude the opening for the inferior mesenteric artery, the wall can be dissected.

    02:16 And this means that the inferior mesenteric artery can become occluded and the hindgut would have a reduction in blood supply.

    02:25 But because of this marginal artery and we have inputs from the superior mesenteric artery is actually possible for the blood to be diverted down in this direction towards the hindgut which can then receive blood from the superior mesenteric artery.

    02:42 So this transition is really important.

    02:45 And this is just what we have focusing on towards the end. These two important transitions.

    02:50 Transitions between the foregut and the midgut, transitions between the midgut and the hindgut.

    02:59 And we can see that these can happen in a number of places, the superior and inferior pancreaticoduodenal arteries And the middle colic and left colic forming the marginal artery.

    03:12 And these are really really quite important in maintaining a sufficient blood supply to the GI tract.

    About the Lecture

    The lecture Inferior Mesenteric Artery – Arterial Supply to the GI Tract by James Pickering, PhD is from the course Abdomen.

    Included Quiz Questions

    1. Marginal
    2. Sigmoidal
    3. Superior rectal
    4. Inferior rectal
    5. Ileocolic
    1. L3
    2. L1
    3. L2
    4. T12
    5. T10
    1. Superior rectal
    2. Inferior rectal
    3. Left colic
    4. Middle colic
    5. Ileocolic

    Author of lecture Inferior Mesenteric Artery – Arterial Supply to the GI Tract

     James Pickering, PhD

    James Pickering, PhD

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    very easy to understand and grasp
    By Sree D. on 15. January 2019 for Inferior Mesenteric Artery – Arterial Supply to the GI Tract

    no professors in my college took me this concept as easy and clearer like Dr. James Pickering

    Learn difficult concepts in minutes!
    By Oluwatomi A. on 22. August 2017 for Inferior Mesenteric Artery – Arterial Supply to the GI Tract

    Why am I rating this lecture at all? I had to pause a video just to wrote this review because I was just so grateful that it was broken down so well with the schematic diagram. I was feeling overwhelmed with the amount of information in the blood supply and wondering if there was a way i can get it down quickly and have the concept clear in my mind. These schematics are awesome and are saving my medical life right now!!!!