Abdomen 2 تفريغ PDF

Block 1.2 lectures 2024-2025 lecture Highlighter key Writers Reviser >> Alaa A...

Block 1.2 lectures 2024-2025 lecture Highlighter key Writers Reviser >> Alaa Alessa Doctor explanation Abbreviation Key information Book >> Abdulhamid Al-Abadi >> Ali Alhakeem 221-222-223 notes References Student explaintion Deleted Abdomen 2 Dr. Omer Musa Mohamed Musa MBBS, MSc. PHD Assistant Professor Department of biomedical science Anatomy division  Theme 6 Intended learning outcomes: By the end of this session every student should be able to: Know the part of the GIT, and their surface anatomy. Esophagus, structure, constriction and neurovascular supply. Stomach, structure parts, location and neurovascular supply. Small intestine, parts, location, different between parts and neurovascular supply. ‫ هذا‬theme ‫من متطلبات الـ‬ Large intestine (block 1.1). anatomy of the colon ‫هي‬ 1.1 ‫هذا رابط التفريغ من البلوك‬ 27/10/2024 2 CONTENTS: Surface anatomy and abdominal regions. GIT arrangement. Esophagus. Stomach. Duodenum. Small intestine. The viscera of the abdomen constitute the majority of the alimentary system: the terminal part of the esophagus and the stomach, intestines, spleen, pancreas, liver, gallbladder, kidneys, and suprarenal glands. When the abdominal cavity is opened to study these organs, it becomes evident that the liver, stomach, and spleen almost fill the domes of the diaphragm. Because they bulge into the thoracic cage, they receive protection from the lower thoracic cage. There are additional organs in the abdomen that have a function in digestion, but don’t have food pass through them (e.g., the liver, gallbladder (these two are called bile system), and the exocrine pancreas. The diaphragm bulges upwards due to the tops of the liver and stomach  For example, the spleen, the liver, A large amount of the thoracic cage is filled with and the gallbladder are totally abdominal contents, because of the diaphragm bulging protected by the ribcage The relations are above our level  Mouth Pharynx Esophagous Stomach Duodenum Through out the journey of Jejunum the food bolus, it passes many Ileum processes of digestion, and absorption. Cecum The method by which food is Ascending colon digested and absorbed is physiology not anatomy Transverse colon descending colon Sigmoid colon Rectum Anal canal  The esophagus is muscle with no Unlike the trachea, which because 1. The esophagus support, so it can be collapsed and flattened it is necessary for air flow, is supported to keep it The esophagus is a muscular tube (approximately 25 cm [10 in] long) with an average diameter of 2 cm that conveys food from the pharynx to the stomach. Convey = move As seen during fluoroscopy (x-ray, using a fluoroscope) after a barium swallow, the esophagus normally has three constrictions. The visualization is mentioned at slide.62 The esophagus’ job is just to Food doesn’t have any processes conduct food from the mouth until reaching the stomach, so to the stomach no delay for food movement The esophagus starts at the level of the pharynx (cricoid cartilage at C6) to the stomach at T10  The esophagus passes through the diaphragm, so there is a gap in the diaphragm called the esophageal hiatus Hiatus = gap ‫فجوة‬ Esophageal The hiatus is at the level of T10, hiatus and opens directly into the stomach 2cm diameter The esophagus (and most of the digestive tract) can dilate and extend for incoming food, so the hiatus can expand if need be.  The physiological barrier that prevents anything from coming out of the stomach is the cardiac sphincter (a.k.a. lower esophageal sphincter) Sphincter = constrictor ‫عاصر‬ The cardiac sphincter is physiological, not anatomical, no specific structure other than constricting muscles = Heartburn (‫ )حرقان‬is when the cardiac sphincter opens and allows the stomach acid to move upwards :pathology ‫ربط بـ‬ The stomach has simple columnar cells, that protect from acidity. While the esophagus is stratified squamous, so acid would lead to the esophagus’ cells becoming simple columnar (Barrett’s esophagus) At the point of the cardiac sphincter we switch from squamous to columnar, so it is called the Columnar squamous-columnar junction (SCJ) same as the external os in the cervix Squamous  Histological structure of the esophagus 4 layer from outer to inner: 1. Serosa /adventitia. 2. Muscularis. 3. Submucosa 4. Mucosa. 1. Serosa is on intraperitoneal organs, while the adventitia is when no peritoneum is present 2. the muscularis is of two layers: outer longitudinal smooth muscle inner circular smooth muscle 3+4. the epithelium in the esophagus is non- keratinized stratified squamous epithelium; it has no functions other than preventing water loss and preventing injury from incoming food  The measurements are because when examining using an endoscopy, the lengths are measured from the teeth. Esophageal constrictions: Cervical constriction (upper esophageal sphincter): at The Cervical constriction is at the beginning of the its beginning at the pharyngoesophageal junction, 15 cm esophagus (at the pharynx) from the incisor teeth; caused by the cricopharyngeus muscle. Thoracic (broncho-aortic) constriction: by the arch of the The Thoracic is close to the aorta, 22.5 cm from the incisor teeth, and then where it is middle of the esophagus (close to aorta and bronchus) crossed by the left main bronchus, 27.5 cm from the incisor teeth. The Diaphragmic is at the Diaphragmatic constriction: at the esophageal hiatus of end of the esophagus the diaphragm, approximately 40 cm from the incisor teeth. (at the stomach)  A barium allows soft tissue to be seen in an x-ray. if it is for the: Esophagus Stomach Colon These constrictions are important Barium swallow Barium meal Barium enema when passing instruments through the esophagus into the stomach, The cervical constriction is up here and when viewing radiographs of patients who are experiencing dysphagia. 15cm (difficulty in swallowing). 23cm The constrictions are also important because these constrictions will be change in cases of infection, tumors, or any other abnormalities 40cm If constrictions appear somewhere else, that is a sign of inflammation or neoplasia The arterial supply of the abdominal part of the esophagus is from the left gastric artery, a branch of the celiac trunk, and the left inferior phrenic artery. Veins inside the epithelial wall of esophagus The venous drainage from the submucosal veins of this part of the esophagus is both to: the portal venous system through the left gastric vein, and into the systemic venous system through esophageal veins entering the azygos vein. Differentiating two similar terms: Splanchnic: abdominal supply (celiac, superior M, inferior M) splenic: spleen supply (branches from celiac)  Arteries that supply the esophagus: Inferior Thyroid Left inferior phrenic Esophageal artery artery Branches Left gastric Subclavian artery artery Celiac artery Heart Thoracic Abdominal Aorta Superior Aorta Aorta mesenteric artery Diaphragm inferior mesenteric artery Veins that drain the esophagus: The upper part of esophagus Systemic venous system Esophageal Azygos Branches vein Superior Vena Heart The lower part Portal venous system of esophagus Abdomen 3 ‫سوف يفصل في محاضرة‬ cava Esophageal Left gastric Branches vein Superior Portal Inferior Mesenteric v. hepatic Vena Inferior vein cava Mesenteric splenic Vein Postal hypertension leads to the increase in the systemic pressure, leading to dilation Dilated and tortuous (twisted) veins are called Varicose veins Portal hypertension could lead to hematemesis (vomiting blood) because of varicose. and portal hypertension could also cause Caput medusae. The lymphatic drainage of the abdominal part of the esophagus is into the left gastric lymph nodes efferent lymphatic vessels from these nodes drain mainly to celiac lymph nodes. The esophagus is innervated by the esophageal plexus, formed by the vagal trunks (becoming anterior and posterior gastric branches), and the thoracic sympathetic trunks via the greater (abdominopelvic) splanchnic nerves and periarterial plexuses around the left gastric and inferior phrenic arteries. Lymph nodes: celiac lymph nodes Sympathetic chain Innervation: esophageal plexus, which is formed by the: Vagus nerve  It is the most dilated part of 2. The stomach the GIT The stomach is the expanded part of the digestive tract between the esophagus and small intestine. An empty stomach is only of slightly larger caliber than the large intestine; however, it is capable of considerable expansion and can hold 2–3 L of food. If the person eats a lot, their stomach can expand even more to accommodate for the large intake Function of the stomach It is specialized for the accumulation of ingested food, which it chemically and mechanically prepares for digestion and passage into the duodenum. The stomach acts as a food blender and reservoir; its chief function is enzymatic digestion. The gastric juice gradually converts a mass of food into a semiliquid mixture, chyme (G. juice), which passes fairly quickly into the duodenum. Chyme = ‫كيموس‬ It is a temporary storage of food The stomach only passes food when the chyme is fully The stomach is the first site of (the esophagus doesn’t store, prepared, so that the intestines can digest the chyme fully. chemical digestion it was only for conveying) The pylorus is what decides when the chyme is ready A person cannot eat food within four hours after a meal because the chyme is not fully made Parts of the stomach: The cardia is right after the cardiac Cardia: the part surrounding the cardiac orifice sphincter, which is after the esophagus (opening), the superior opening or inlet of the stomach. Fundus: the dilated superior part that is related to the left It is higher than the esophagus’ entrance; dome of the diaphragm, limited inferiorly by the horizontal Therefore, it is filled with gas. plane of the cardiac orifice. Body: the major part of the stomach between the fundus and pyloric antrum. Pyloric part: the funnel-shaped outflow region of the The pylorus has the control of chyme stomach; its wider part, the pyloric antrum, leads into the movement, over eating leads to it being pyloric canal, its narrower part, The pylorus (G., forced to open gatekeeper) is the distal, sphincteric region of the pyloric part. The exact shape of the stomach is variable in people (based on height and weight) There are two curves (‫)انحناءات‬ around the stomach: lesser curvature greater curvature Interior of stomach The smooth surface of the gastric mucosa is reddish brown during life, except in the pyloric part, where it is pink, it is covered by a continuous mucous layer. When contracted, the gastric mucosa is thrown into longitudinal ridges or wrinkles called gastric folds (gastric rugae);which diminish as the stomach is distended (fills). When the stomach is emptied out of food, it Unlike the small intestine, in collapses and has temporary folds (rugae) which folds are almost permanent Transpyloric plane is, almost, at L1 The bed of the stomach I.e., the organs around the stomach (relations of the stomach) on which the stomach rests, is formed by: 1. the left dome of the diaphragm. 2. Spleen. 3. left kidney and suprarenal gland. 4. splenic artery. 5. Pancreas. 6. transverse mesocolon. The splanchnic artery, is not a thing. Splanchnic arteries are the abdominal arteries Arterial supply of the stomach The rich arterial supply of the stomach arises from the celiac trunk and its branches. Most blood is supplied by anastomoses formed along The gastric arteries and the gastroepiploic aa. anastomose at the stomach’s curvatures the lesser curvature by the right and left gastric arteries, and along the greater curvature by the right and left gastro-omental (gastroepiploic) arteries. epiploic = omental The fundus and upper body receive blood from the short and posterior gastric arteries. vature vature cur Cur er ss Le er at re G Gilroy’s anatomy atlas: p.207  Arteries that supply the Stomach: er curva at tu e Fundus Gr re Left Right Right Gastro- Left Gastro- Short omental a. omental a. Gastric a. Gastric a. Gastric a. es r L e ser at u C urv Hepatic artery Splenic Artery (right side) (left side) Heart Abdominal Aorta Aorta Celiac artery The veins of the stomach The veins of the stomach parallel the arteries in position and course. The right and left gastric veins drain into the hepatic All stomach drainage goes into the portal vein; the short gastric veins and left gastro- hepatic system (unlike esophagus). omental veins drain into the splenic vein, which joins the The veins are either directly into the superior mesenteric vein (SMV) to form the hepatic portal main hepatic vein, or reach the vein. superior mesenteric vein before. The right gastro-omental vein empties in the SMV. A prepyloric vein ascends over the pylorus to the right gastric vein. Which is used for identifying the pylorus. urvature vature cur er C er ss at Le re G Gilroy’s anatomy atlas: p.215 Veins that drain the Stomach: Portal venous system ature Left Direct gastric v. r rv cu Lesse Right gastric v. Heart Portal Inferior ndus Short gastric v. hepatic Vena u vein cava F Indirect Left Splenic v. ure at gastro- omental v. r curv Right e Superior t Grea gastro- mesenteric v. omental v. The gastric lymphatic The gastric lymphatic vessels accompany the arteries of the stomach. Lymph from the superior two thirds of the stomach drains to the gastric lymph nodes; lymph from the fundus and superior part of the body of the stomach also drains to the pancreaticosplenic lymph nodes. Lymph from the right two thirds of the inferior third of the stomach drains along the right gastro- omental vessels to the pyloric lymph nodes. Lymph from the left one third of the greater curvature drains to the pancreaticoduodenal lymph nodes. Which finally drain to celiac node. The only important part Autonomic supply of the stomach The parasympathetic nerve supply of the stomach is from the anterior vagal trunk (derived mainly from the left Vagus) and posterior vagal trunk (derived mainly from the right Vagus), which enter the abdomen through the esophageal hiatus. The sympathetic nerve supply of the stomach, from the T6 through T9 segments of the spinal cord, passes to the celiac plexus through the greater splanchnic nerve and is distributed through the plexuses around the gastric and gastro-omental arteries. 3. Small intestine The small intestine, consisting of the duodenum, jejunum, and ileum, is the primary site for absorption of nutrients from ingested materials. It extends from the pylorus to the ileocecal junction where the ileum joins the cecum. The pyloric part of the stomach empties into the duodenum, duodenal admission being regulated by the pylorus. ileo = ileum & cecal = cecum This means it is a junction between the ileum & the cecum  In Latin, the term "duodenum" means 12 3. 1. The duodenum fingers, which is roughly the length of the duodenum. 12 fingers = 24 or 24 cm The duodenum (L. breadth of 12 fingers), C-shaped the first and shortest (25 cm) part of the small intestine, is also the widest and most fixed part. The first 1 inch of The duodenum pursues a C-shaped course the duodenum duodenojejunal around the head of the pancreas. Descending colon flexure (junction) Jejunum head of the It begins at the pylorus on the right side pancreas. and ends at the duodenojejunal flexure (junction) on the left side. The duodenum is the only part of Mostly fixed by peritoneum to the posterior the small intestine which is almost retroperitoneal (except the first 1 abdominal wall and is considered partially inch), meaning that it is behind the retroperitoneal. peritoneum that lines the posterior abdominal wall. posterior view  The length of each part is not The duodenum is divisible into four parts: important Superior (first) part: short (approximately 5 cm) and lies anterolateral to the body of the foregut midgut L1 vertebra Descending (second) part: longer (7–10 cm) The first part The lower and descends along the right sides of the L1– of the duodenum half of the second part, L3 vertebrae. and the upper half of the third Inferior (third) part: 6–8 cm long and crosses the second part, and the fourth part the L3 vertebra. part Ascending (fourth) part: short (5 cm) and begins at the left of the L3 vertebra and rises superiorly as far as the superior border of the Right side L2 vertebra The descending part of the duodenum runs inferiorly, curving around the head of the pancreas. The bile and main pancreatic ducts enter its posteromedial wall. These ducts usually unite to form the The second part of the duodenum receives secretions from the liver (biliary system) and the hepatopancreatic ampulla, which opens pancreas at two sites called: on an eminence, called the major duodenal Major Duodenal Minor Duodenal papilla, located posteromedially in the Papilla Papilla descending duodenum. This is the site Above the major The hepatopancreatic ampulla is formed where the common duodenal papilla, by the convergence of the common bile bile duct and the there is an accessory duct and the main pancreatic duct. It main pancreatic duct pancreatic duct that open into the opens into the minor opens into the duodenum at the major duodenum. duodenal papilla duodenal papilla The arteries of the duodenum a rise from the celiac trunk and the superior mesenteric artery (this means………..). The celiac trunk, via the gastroduodenal artery and its branch, the superior pancreaticoduodenal artery, supplies the Proximal - Foregut major duodenal papilla duodenum proximal to the entry of the bile Distal - Midgut duct into the descending part of the duodenum. The superior mesenteric artery, through its branch, the inferior pancreaticoduodenal artery. The veins of the duodenum follow the arteries and drain into the hepatic portal vein, some directly and others indirectly, through the superior mesenteric and splenic veins. The lymphatic vessels of the duodenum follow the arteries. drain into the superior mesenteric lymph nodes and the celiac lymph nodes. 3. 2. Jejunum and 3.3. Ileum The second part of the small intestine, the jejunum, begins at the duodenojejunal. The third part of the small intestine, the ileum, ends at the ileocecal junction, the union of the terminal ileum and the cecum. Together, the jejunum and ileum are 6–7 m long, the jejunum constituting approximately two fifths and the ileum approximately three fifths of the intraperitoneal section of the small intestine.  One of the ways to differentiate is by their position, as mentioned in the slide. They are intraperitoneal and have mesentery that connects them to the posterior abdominal wall, called the small intestinal mesentery, which helps in coiling and blood supply. Most of the jejunum lies in the left upper quadrant (LUQ) of the infracolic compartment, whereas most of the ileum lies in the right lower quadrant (RLQ). The terminal ileum usually lies in the pelvis from which it ascends, ending in the medial aspect of the cecum. Although no clear line of demarcation between the jejunum and ileum exists, they have distinctive characteristics that are surgically important. Composition of the Intestine Serosa Muscular Layer Submucosa Mucosa (simple columnar epithelium) There is no adventitia because they are intraperitoneal. Anterior Part of the Small Intestine Proximal Jejunum: Circular folds (plicae circulares) Proximal Ileum: Circular folds (plicae circulares) Terminal Ileum: smooth (meaning no or less absorption)  The superior mesenteric artery (SMA) arises from the abdominal aorta at the level of the L1 vertebra supplies the jejunum and ileum via 15-18 jejunal and ileal arteries. These arteries unite to form loops or arches, called arterial arcades, which give rise to straight arteries, called vasa recta. vasa recta = ‫الشريان المستقيم‬ The superior mesenteric vein drains the jejunum and ileum. It Liver lies anterior and to the right of the Splenic Vein SMA in the root of the mesentery. Hepatic portal vein The SMV ends posterior to the Superior Mesenteric Artery Superior Mesenteric Vein neck of the pancreas, where it Abdominal Aorta unites with the splenic vein to form the hepatic portal vein. SMA: Superior Mesenteric Artery. Specialized lymphatic vessels in the intestinal villi that absorb fat are called lacteals. They empty their milk-like fluid into the lymphatic plexuses in the walls of the jejunum and ileum. The lacteals drain in turn into lymphatic vessels between the layers of the mesentery which drain finally to SMA nodes The sympathetic fibers in the nerves to the jejunum and ileum originate in the T8–T10 and reach the superior mesenteric nerve plexus through the sympathetic trunks and thoracic abdominopelvic (greater, lesser, and least) splanchnic nerves. The parasympathetic fibers in the nerves to the jejunum and ileum derive from the posterior vagal trunks. To synapse in myenteric and submucosal plexuses in the intestinal wall. The intestine is insensitive to most pain stimuli, including cutting and burning; however, it is sensitive to distension Gases distension that is perceived as colic (spasmodic abdominal pains or “intestinal cramps”). The differences are important. The remaining slides are not important  team Wishes you the best