Anatomy. Ruba Mahafzah 18/11/2015. Mohammad Allouh. 1 P a g e

Transcription

1 Anatomy Ruba Mahafzah 18/11/2015 Mohammad Allouh 1 P a g e

2 In the previous lecture we started speaking about the liver. We said that the liver is composed of 2 main surfaces: 1. Convex diaphragmatic surface : that extends superior anterior that its opposite to the diaphragm. 2. Visceral surface : inferior posterior surface, opposite to the abdominal viscera. We spoke also that the diaphragmatic surface have some reflections of the peritoneum, for ex. Anteriorly we have 2 layers of peritoneum. Remember: whenever you have a mesentery its for intestine, mesocolon for large intestine, omentum in the stomach, ligament on a solid organ. But these are not true ligaments, these are reflections of the peritoneum, but we call them ligament to distinguish this part of peritoneum around solid organ. In any case you need always 2 layers of visceral Peritoneum, so all of these are double layers of peritoneum not only single layer. 2 P a g e

3 We look to the liver here from above, so this will go and Reflects superiorly opposite to the diaphragm and on the diaphragm this layer will become parietal peritoneum and return down again, so this is not a ligament. In order to become a ligament, this part of peritoneum needs another layer. Remember this when we speak about the greater omentum, we need 2 layers: One is covering the stomach anteriorly The other covering the stomach from the posterior surface Once they descends doen below the stomach from the greater curvature, these 2 layers will become the greater omentum. Once they go above from the lesser curvature of the stomach towards the liver, they would become lesser omentum. So, always double layer of peritoneum.. Here we see 2 layers of peritoneum : One is coming from the right side covering the liver and reflects anteriorly. 3 P a g e

4 The other from the left and reflects anteriorly to the anterior abdominal wall & they reflect back and spread to become pariteal peritoneum. These 2 reflections here we call them The Falciform Ligament. As the falciform ligament expands superiorly, the 2 layers start to separate from each other, bcz one of them will go to the right side while the other layer of the falciform will go to the left side. As they split far away they start to form an area without peritoneum very rough surface. This is the initiation of the bare area of the liver. As they split far away or separated they produce the bare area of the liver. The right one will go to the right and the left will go to the left. Now on the posterior surface of the peritoneum there are other 2 parts of the same sac of peritoneum covering. This is the posterior covering of the peritoneum for the liver, so this is part of peritoneum covering the posterior surface of the liver. It will go also to the diaphragm but this time it will reflact and goes to the posterior aspect of the abdominal wall. This one will reflect and go anterior. This one will reflect and go posterior. This is the anterior layer. This is the posterior layer go posterior posterior peritoneu 4 P a g e

5 Now this anterior layer & this posterior layer together we call them a ligament, this ligament is almost round in shape like a crown over the head of the liver so we would call it CORONARY LIGAMENT of the liver. Anterior layer Posterior layer You see how much they are still separated from each other, so doesn t mean that these layers should be close to each other, they are far away separated This area between the is still the same as here which is the bare area of the liver. So the bare area of the liver is between the 2 layers mainly of the coronary ligament As the 2 layers now of the coronary ligament becomes closer to each other, as the liver becomes decreased in thickness in the right angle, they will go and reflect on the diaphragm. we The 2 layers here are more or less triangular in shape so Will call them THE RIGHT TRIANGULAR LIGAMENT. 5 P a g e

6 In the left side now bcz the left lobe is much smaller than the right lobe as you see, the posterior layer will become closer to the anterior layer. So we don t have a coronary ligament,, why? Bcz the left lobe is much smaller, much thinner, so the 2 layers are closed, so they don t form that round shape of the crown, so we don t call it coronary ligament, instead these 2 layers will be called now.. They are more or less triangular in shape so all of this will be called: THE LEFT TRIANGULAR LIGAMENT So remember this, we have 4 reflections of peritoneum on the diaphragmatic surface of the liver. These reflrctions are: 1. The falciform ligament anteriorly 2. Coronary ligament superiorly on the right 3. Right triangular ligament 4. Left triangular ligament These ligaments are reflections of the peritoneum, however if we looked to the visceral surface of the liver we could see 2 ligaments, which are true ligaments. What do I mean by true ligaments? Dense connective tissue, collagen fibers, forming a real ligament, so not reflection of peritoneum 6 P a g e

7 One of these ligament if we can see is this one, it comes from the umbilicus inside your body, which means from the anterior abdominal wall and this ligament or these collagen fibers will move and they will adhere on the visceral surface of the liver, they will split the left lobe as you see into qyadrate and left, we call it LIGAMENTUM TERES or the round ligament of the liver, as it moves from the umbilicus all the way until it get into the left branch of the portal vein as you see, so this what we call the ligamentum teres in the latin for the round ligament. Why it comes from the umbilicus to the portal vein? Bcz its actually passes between the 2 layers of the falciform, if this is the falciform ligament which is the reflection of the peritoneum, it is made up of 2 layers of peritoneum, this layer( )will go to the right and this layer will go to the left ( ), in between the 2 layers of 7 P a g e

8 falciform you see a collagen fiber passing( ), this is the ligamentum teres or the round ligament of the liver. The lgamentum teres or the round ligament of the liver is an embryolgical remnant of the umbilical vein which is the largest structure in the umbilical cord. Now from the left branch of the portal vein thies ligamentum teres ends. Another ligament go on the posterior aspect of the visceral of the liver. This ligament from the left branch of the portal vein to the inferior vena cava (IVC), this ligament is atrue ligament, its true collagen fibers. We would call it LIGAMENTUM VENOSUM in latin, which in english means the venous ligament. This venous ligament or ligamentu venosum is the remnant of what we call it DUCTUS VENOSUS or venous duct in embryo. So on the vesceral surface I have 2true ligaments : 1. The ligamentum teres (round ligament) you see it from the umbilicus anteriorly all the way to the left branch of the portal vein. 2. Ligamentum venosum (venous ligament) from the left branch of the portal vein to the IVC. If you think why they are there? why they are embryologial remnant? During embryolgical development the liver is still not functioning & the process of filtration is not carried out bcz most of the blood going to the fetus is coming from theplacenta المشيمة it s a 8 P a g e

9 maternal blood blood من االم as this blood pass from the placenta, it pass with the umbilical cord which is in red here is the umbilical vein. Its like the pulmunary circulation its vein bcz its returning blood to the body of the fetus & the artery which removes the deoxygenated blood in the umbilical cord we call it the umbilical artery. However, they take the deoxygenated blood from the fetus to the placenta. Its inverted circulation not like the systemic, its similar to the pulmonary circulatiion, that s why you see them in different colors. So the umbilical vein taking blood from placenta, this blood is already oxygenated, filtered & rich in nutrients from the mother so no need for filtration process. So what happening here is that it goes all the way & joins the left branch of the portal vein. Since there is no functioning liver yet, no need for blood to get into the liver, do. تحويلة there will be a shunt placenta This shunt is a small duct that will take will take this blood & returns it directly through IVC to the heart, so this the shunt. Blood comes directly through umbilical vein from there to this venous duct into the IVC & directly to the heart 9 P a g e

10 At the late stage of development when the liver start to function, what will happen now? These ducts & this umbilical vein start to closure & after birth when you cut the umbilical cordthey completely obliterated & replaced by ligaments بسكروا ligamentum teres. Quick review How many surfaces of the liver? 2 diaphragmatic surface & visceral surface How many areas without peritoneum? 3 on the diaphramatic there is alrge one called bare area, it starts between the falciform & expand between the coronary on the visceral surface there are 2areas, where the gall bladder is resting, the bed of gall bladder bcz its fairly attached to the liver, the peritoneum cover above it. the hilum of the liver or the porta hepatis 10 P a g e

11 So 3 areas without peritoneum : bare area, bed for gall bladder & porta hepatis. How many lobes in the liver? 4 or 2 depends on what you are speaking.. Anatomically 4 bcz there are 2 ligaments that producing a groove اخدود on the left lobe separating it into 3 lobes :quadrate, caudate &left, and right lobe Functionally quadrate, caudate &left lobe of the liver are functioning as one unit. So physiologically speaking from the function not from the form there are 2 lobes (left&right) and that s why you have 2 portal branches, 2 hepatic arterial branches & 2 branches of the bile duct (right&left hepatic). How many ligamnts on the liver? 6 anterioly 1 falciform ligament superiorly 3 coronary ligament(we don t call it right coronary bcz we don t have left. right triangular left triangular inferiorly 2 teres & venosum (embriological remnant there are true ligaments). Porta hepatis located between which lobes anteriorly & posteriorly? 11 P a g e

12 Porta hepatis is in the middle of the visceral surface of the liver, so.. Anterior to it you will see quadrate Behind it you will see tale (caudate) To the left you will see the left lobe To the right you will see the right lobe And that s the liver. Blood supply to liver There are 2 blood sources of the liver bcz of its function. One of the main function of the liver we said in rhis lecture is filtration. To filter that all blood coming from the intestine bcz during the absorption process we afraid that many foreign particles, many toxins, many micro organisms (Mos) can be absorped from the lumen of the intestine into this blood. We cannot retuen this blood directly to the heart, instes we need a filterand this filter is produce by the portal circulation. The blood from superior & inferior mesenteric artery, which are the arteries that draining the midgut & the hind duct & part from 12 P a g e

13 the celiac also from the foregut. All will be gathered in a way into a large vein we call it portal vein. This is the large one is the portal vein, the largest structure in the triad is vein and its always posterior in the triad. Anteriorly, middle sized hepatic artery, its located on the triad always coming from the left side. On the right side of the triad you will see the common bile duct. So anterior to the right and it makes sence the common bile duct bcz its coming from the liver from the right. Anterior to the left is the hepatic artery bcz its coming from the celiac, from the left side and most posterior is the portal vein. So the portal vein is formed by 2 veins : splenic & superior mesenteric (we will speak about them in the lecture of vasculization). The blood now once it enters from the portal vein and hepatic artery, this is the portal triad, look carefully.. Anterior to the left is the hepatic artery Anterior to the right is the bile duct More posterior is the portal vein 13 P a g e

14 The blood comes from the hepatic artery and enters the liver carrying O₂ (oxygenated blood) for what? for oxygenation of the hepatocytes, the liver cells (that s the main function of the blood from the hepatic). However, in the portal vein the blood will come & enters also in the liver for filtration, this blood is rich in nutrientsbcz its coming from the intestine but also unfortunately its rich in toxins and foreign structures.so we need to filter it. So, one for filtration and for oxygenation. The blood now from both sources will be filtered & provide oxygenation for hepatocytes and the whole blood. Now the mixed one will drain posteriorlythrough smaller veins they will go and drain posteriorly in the IVC. These smaller veins one from the right and one from the left we cll them hepatic veins. There are something called hepatic veins & something called portal veins to distinguish between them. The portal vein or which thay call it hepatic portal vein, they call it hepatic to distinguish it from another portal vein in your body. There are 2 portal circulations in the body, its your HW wher is the other portal circulation :p 14 P a g e

15 So we call it hepatic portal veins to distinguish it from the hepatic veinss. Hepatic portal veins: is the portal vein that brings the blood from the gut to be filtered into liver, so it enters the liver. However posteriorly on the posterior surface of the liver there are hepatic veins which drains blood from the liver into IVC. Bile duct Bile duct very easy :p we have 2 branches (left & right hepatics) once they joins I would call them COMMON HEPATIC. The common hepatic now as it descends up small duct from the gallbladder eill join it cystic duct. why its cystic? bcz its draining a cyst cyst means fluid filled sac its something resemblanceto the shape of the gall bladder so we call it a cyst, the gall bladder is more or less a cyst. That s why in all terminolgy, in all the classic anatomy they were call it cyst and its duct is called CYSTIC DUCT. so this is the cystic duct which will join the common hepatic. 15 P a g e

16 Now this duct will no longer be hepatic bcz its coming from 2 organs instead of one, so I cannot call it common hepatic, I will call it COMMON BILE. Look carefully for the relation this is imp for who wants to be a GI surgeon. The bile duct as it descends it goes behind the first part of duodenum (retro peritoneum) so the duct descends down within the peritoneum. At this level it will leave the peritoneum and go behind the duodenum so now it lose its peritoneum covering. The part of peritoneum that covers the first 2cms and ascends it will cover it ( hepato duodenum ligament, lesser omentum from the stomach to the liver) its covering these structures, when it goes behind lesser omentum there is no lesser curvature of the stomach so now it goes retro peritoneum. Its within the hepatoduodenum ligament until the duodenum, behind the first part of duodenum it becomes retro peritoneum& 16 P a g e

17 descends behind the duodenum & behind the head of pancreas (retro & secondary). Behind the first part of duodenum, behind the head of pancreas,then it will pearced the head of pancreas, penetrating the head of pancreas and get within thw tissue of pancreas. So when you try to find it, it will form blunt dissection بتبعد tissue of the pancreas to see how it is penetrating it & join the main pancreatic duct. Once it joins the main pancreatic duct, they will become a very large dilated duct, I will call it the AMPULLA OF VATER. Behind the first part of duodenum, behind the head of pancreas passing anterior to join the main pancreatic duct, they will become a very large duct we will call it ampulla of vater will open into the second part of duodenum which we call it the descending part. Once it opens there it will form an elevation in the wall of duodenum produced by the opening of the ampulla of vater, I would call it major duodenal papella. So the dilated duct from bile & pancreas is the ampulla of vater & once it opens it will form an elevation I would call it the major duodenal papella. Ampulla of vater 17 P a g e

18 Gall bladder Gall bladder is the storage & concentration of bile so it doesn t secrete the bile, it stores the extra bile secreted by the liver. Its made up from fundus, body & neck. From the neck there will be the cystic duct wich joins the common hepatic to form common bile. Blood supply of the gall bladder is imp. Most of the time, 80-90% of the time comes from the right hepatic artery & it make sence, why? bcz of closer relation to right lobe of the liver, its not on the left, its on the right. The right branch before it enters into the liver, it will give a small branch to the cystic duct we call it a. CYSTIC ARTERY This is very imp during cholecystectomy (removal of gall bladder when it is inflamed), you always before removing it or cutting it you have to make sure to ligate this artery. How can you find it? Follow the hepatic artery, there is right & left hepatic Branch, you go with the right hepatic artery. Now you can see a small branch going toward the gall bladder. So you follow the large artery until its smaller branches. 18 P a g e

19 Pacnreas Pancreas is both exocrine & endocrine gland. The difference is where you secrete. the exocrine : you secrete into a body cavity like the lumen of the duct, or to the outside of your body like the sweat gland, sebaceous glands secretes hydrolytic enzymes like trypsine, pancreatic lipases into the duodenum. endocrine : you secrete into blood, into the venous circulation of the blood are cells gathers to secrete insoline & glucagon, we would call them islets of langerhans. The pancreas is secondary retroperitonial structure. ** ex. of primary & secondary retroperitoneum : primary kidneys, ureters, suprarenal gland secondary gut (remaining part of the duct retroperitoneum like the duodenum, ascending column, descending column, pancreas. As an accessory oragns that means they develop within the peritoneum. Bcz of the rotations & the development of the gut some of them will move backward and lose its peritoneal covering, bcz its reflection not a ligament. So once it slips between them can easily go behind the peritoneum. The pancreas is retroperitoneal except the tail (intraperitoneum) Why? how can the tail becomes intraperitoneum? 19 P a g e

20 If you look to the sructure here, this is the parietal peritoneum it reflects to cover the spleen, and stomach and we have the lesser omentum, hepato duodenal ligament, and you can see portal vein posterior, bile duct anterior to the right, hepatic artery anterior to the left. When we come back the lesser omentum it covers & reflects spleen. Pancreas behind the stomach, retroperitoneum, when its inflamed it mnemics the inflammation into the stomach so they confuse between gastritis and pancreatitis bcz they are close to each other. As it descends it goes from the left side here all the way behind the parietal peritoneum until it tails enter between these 2 layers of the visceral peritoneum. So the tail enters here and return and continues as neck and head. Now we are agreed that when we have 2 layers of visceral peritoneum reflecting from a solid organ like the spleen, I would call these refelctions ligaments(they are the same reflections in the liver) However in the spleen you will have 2 ligaments : one reflection of the peritoneum going backwards toward the kidney splenico-renal ligament 20 P a g e

21 other reflection from the spleen to the stomach gastrosplenic ligament, when its reflicting up (gastro-phrenic) when its relecting down (gastro-colic بتنزل وبتعمل زي المريلة ) in the greater omentum. Posteriorly between the spleen and kidney spleno-renal ligament. Between the 2 layers of the spleno- renal ligament the بحشر حاله tail of the pancreas will be crammed here There are peritoneal fluids behind it that s why the tail of the pancreas intra peritoneum, bcz its covered posteriorly and anteriorly with peritoneum, its crammed within the splenico-renal ligament. But the remainig part there is peritoneum behind it so its retro peritoneum. Spleen is an intra peritoneal structure, it has 2 ligaments : Splenico renal psteriorly gastro splenic anteriorly Its resting on the ribs 9,10,11. However its axis corresponds mostly to the left 10 th rib, so its mainly over the rib # 10 (this is an imp relation) Its attached to the stomach through gastro splenic ligament which is part of the greater omentum. Its attached to the kidney, the left one through splenico renal ligament, from spleen to the kidney. 21 P a g e

22 Introduction to histology The histology of the gut is almost similar 4 layers (inside outside) mucosa Its not just an epithelial lining. Below the epithelial lining there is a basement membrane or what we call it THE MAIN LAMINA or LAMINA PROPRIA muscle layer. After the lamina propria there is another muscle layer very thin its related to the mucosa bcz its contraction will squeeze on the mucosa, on the lamina propria, so any gland here will be producing secretions. So this muscle layer is not related to the movement its related to the secretions. Similar to the main muscle its inner circular, outer logitudinal but I would call it since its more related to the mucosa MUSCULARIS MUCOSA, it s part of the mucosa. Remember that mucosa is made up of 3 parts : 1. The epithelial lining which varies as you go through the duct and we spoke about these variations. 2. The lamina propria loose areolar connective tissue. 3. Muscularis mucosa the small layer which made from inner circular, outer longitudinal. Now after muscularis mucosa you will got a dense irregular connective tissue not loose bcz it contains rigid collagen fibers to 22 P a g e

23 Have a strong to support the blood vessels, the vascularization. That s the function of this layer & I would call it SUBMUCOSA. After submucosa there is the maun muscular layer which responsible for motility, for peristaltic movement, this muscle layer I would call it to distinguish it from the smaller one MUSCULARIS EXTERNA. Its external to the outside away from mucosa, the most external. The same inner circular & outer longitudinal The inner circular will function in constriction Outer longitudinal will function in continuation of peristaltic contraction **Together they will produce this peristaltic motility. So muscularis externa, inner circular & outer longitudinal are responsible for peristaltic activity. Last layer from outside.. again we will have loose areolar connective tissue, this layer called ADVENTITIA & its covered with visceral peritoneum I would call it now SEROSA. So when we have adventitia + peritoneum = serosa If there is no peritoneum = adventitia If I asked you about any organ if its retro peritoneum or intra it depends now which layer it will have.. For thoracic esophagus adventitia If you look through a view of the esophagus.. 23 P a g e

24 adventitia Muscularis longitudinal Muscularis inner submucosa Epithelial lining with lamina propria muscularis mucosa So if the organ is retro peritoneal its covered with advetitia like the duodenum If its intra peritoneal like the jejunum its serosa And in the next lecture we will speak about the histology of the يعطيكو العافية )":.. GIT DONE BY : ROBBEN :P ** I hope you found this lecture soft regardless the number of pages ** I apologize for any mistake or any non understandable points please don t hesitate to ask about any thing **this sheat is dedicated to Tabooleh 3 < you really saved me from being a psycho :3 thanks a lot for taking care : ) : ) عملتو ازرق مشانك < 3 **dedicated to deema **dedicated to all of you عون and may the odds be ever in your favor 24 P a g e