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Blood Supply – Arterial Supply to the GI Tract

by James Pickering, PhD
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    00:01 In this lecture we are going to look at the arterial supply to the gastrointestinal tract.

    00:08 So we are going to look at the numerous arteries that supply nutrient rich, oxygen rich blood to the gastrointestinal tract, the duodenum, the stomach, the colon, parts of the small intestine and also to the accessory organs of digestion like the pancreas and the liver.

    00:27 What we need to do is first of all imagine the gastrointestinal tract as one long continuous tube and we can divide it into foregut, midgut and hindgut.

    00:39 And what we are going to do, is we are going to look at the organs that make up the foregut and explain how they are supplied by the coeliac trunk.

    00:47 We will then look at the division between the foregut and the midgut detail the midgut organs and how they're supplied by branches of the superior mesenteric artery And then look at the organs that constitute the hindgut and how they're supplied by the inferior mesenteric artery.

    01:06 And then we will look at some important transitions that occur between forgut-midgut and the midgut-hindgut.

    01:16 So if we just look at the schematic first of all. Then what I want to do, is try and explain the aorta running parallel to the gastrointestinal tract.

    01:27 So this is the gastrointestinal tract all the way along here. This is the anterior aspect and this is the posterior aspect, anterior aspect and the posterior aspect.

    01:38 So this view really is as if you are lying on your back and someone is looking at you from the side. What we can see is the diaphragm indicated here in green.

    01:49 The aorta passes through the diaphragm and at various points along the course, the coeliac trunk is given off; the superior mesenteric artery is given off and the inferior mesenteric artery is given off.

    02:03 So at T12, L1 and L3, these vertebral levels, we have the coeliac trunk, or the superior mesenteric artery or the inferior mesenteric artery.

    02:15 If we then look to the gastrointestinal tract, we can see that the GI tract is split into foregut, midgut and hidgut.

    02:26 Now, the separation between the foregut and the midgut, this occurs at the duodenum; specifically the major duodenal papilla. That separates the foregut from the midgut.

    02:39 And remember the major duodenal papilla was half way down the descending part of the duodenum.

    02:46 The midgut becomes the hindgut 2/3rd of the way along the transverse colon.

    02:54 So 2/3rd of the transverse colon is midgut and then the remaining 3rd is hindgut.

    03:01 And that's important when we look at which artery supply which parts of the GI tract.

    03:08 So simply here in this diagram, we can see that the coeliac trunk is going to give rise to the branches that supply the foregut. We can see the superior mesenteric artery is going to give rise to branches that supply the midgut.

    03:22 And finally we can see the branches from the inferior mesenteric artery are going to supply the hindgut.

    03:30 These dotted lines here represent the transitions between the blood supply to the foregut and midgut. We saw this, when we looked at the superior and inferior pancreaticoduodenal arteries at the head of the pancreas and the duodenum.

    03:49 Between the midgut and the hindgut, we had the transition that formed the marginal artery inputs primarily from the middle colic and left colic artery.

    03:58 With the middle colic coming from the superior mesenteric and the left colic coming from the inferior mesenteric artery.

    04:06 So these foregut, midgut and hindgut regions have specific blood supply.

    04:11 But there is also a transitional area between them.

    04:16 So we are going to look at the specific branches from the coeliac trunk, superior mesenteric artery inferior mesenteric artery and also consider those transitions.

    04:26 So here we can see a general, more anatomical drawing of the blood supply to the GI tract. We can see we have got the abdominal aorta up here.

    04:37 We can see it's passing down through the diaphragm.

    04:40 Remember, the aorta passes through the diaphragm through the aortic hiatus at about T12, oesophagus T10 and the inferior vena cava T8.

    04:51 So the aorta passes down and then really we can pick it up again around about here. Where we have the coeliac trunk pretty much immediately being given off.

    05:02 So the coeliac trunk would be given off really at the lower border of T12.

    05:07 We can see that the coeliac trunk has a number of branches. We can see a branch goes in this direction in this direction, in this direction. Three branches that are going to go and supply the foregut.

    05:19 We can see we have the hepatic artery that is going towards the liver. We have got a gastric artery that is running up towards the stomach. And we can see we have got a splenic artery that running towards the spleen.

    05:34 Coming off these blood vessels, we have smaller vessels that are going towards the pancreas.

    05:40 We can see the hepatic artery going towards the duodenum, going towards the head of the pancreas.

    05:45 All coming off the coeliac trunk.

    05:48 If we were to look at the superior mesenteric artery here, superior mesenteric artery comes off at about L1.

    05:56 And we can see, this is giving blood really that is passing to the jejunum into the ileum It also gives rise to a blood vessel that passes up to the pancreas and the duodenum, the inferior pancreaticoduodenal arteries.

    06:10 And we can see it also giving rise to the blood vessels that go to the caecum, ascending colon and also to the transverse colon.

    06:19 We can see we have the inferior mesenteric artery. This originates from about L3 And this supplies blood to the hindgut. So we can see we have left colic arteries, sigmoidal arteries and the superior rectal artery that passes through the rectum.

    06:37 We can then see these black circles which are indicating the important transition.

    06:43 The transitions between the foregut and the midgut, the pancreaticoduodenal arteries.

    06:48 And the transition between the midgut and hindgut at the marginal artery here, from the middle colic and the left colic. So this is the general scheme of how the gastrointestinal tract receives its arterial blood to carry out its vitally important function of providing oxygen to the tissues to work and nutrients to provide them with sufficient energy.


    About the Lecture

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


    Included Quiz Questions

    1. T12
    2. T6
    3. T8
    4. T10
    1. Celiac trunk
    2. Superior mesenteric artery
    3. Inferior mesenteric artery
    1. L3
    2. T12
    3. L1
    1. Superior mesenteric
    2. Celiac trunk
    3. Thoracic aorta
    4. Abdominal aorta
    5. Inferior mesenteric

    Author of lecture Blood Supply – Arterial Supply to the GI Tract

     James Pickering, PhD

    James Pickering, PhD


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