HBF-II LEC 38 Gross Anatomy Stomach Liver Gall Bladder Notes 2024 PDF

Gross Anatomy: Stomach, Liver, Gallbladder Page 1 of 21 Dr. Dennis Goebel LEARNING OBJECTIVES 1. Use anatomical terminology to describe the anatomical features of the stomach: A. Describe the anatomical regions of the stomach. B. Describe the muscula...

Gross Anatomy: Stomach, Liver, Gallbladder Page 1 of 21 Dr. Dennis Goebel LEARNING OBJECTIVES 1. Use anatomical terminology to describe the anatomical features of the stomach: A. Describe the anatomical regions of the stomach. B. Describe the muscular layers and mucosal lining of the stomach. C. Describe the anatomical relationships of the stomach, and its attachments to other structures/organs. D. Describe the arterial supply of the stomach and their anastomotic connections. E. Understand and describe the route of venous return, lymphatic drainage of the stomach. F. Understand the sources for Parasympathetic and Sympathetic innervation of the stomach and how pain and stretch sensations from the stomach are relayed. 2. Use anatomical terminology to describe the anatomical features of the liver: A. Describe the general functions of the liver. B. Describe anatomical features and relationships of the liver to the body wall, the thoracic diaphragm, and the ligaments that suspend it to the thoracic diaphragm. C. Describe the visceral surface of the liver, its lobes and their relationships to surrounding organs. D. Describe the routes of arterial and portal vein blood supply to the liver. E. Describe the anatomical region for venous return of the liver into the inferior vena cava. F. Describe the functional lobes, arterial supply, and venous return through the hepatic portal system, and relationships to other structures/organs. 3. Describe the gallbladder: anatomical features and relationships to other structures, formation of the bile duct, functions, arterial supply, and innervation. 4. Apply anatomical knowledge to clinical problems involving stomach, liver, and gall bladder. Gross Anatomy: Stomach, Liver, Gallbladder Page 2 of 21 Dr. Dennis Goebel SESSION OUTLINE I. Stomach A. Definition B. Functions 1. Digestion of food by 2 mechanisms: chemical and mechanical 2. Mucosal glandular secretions 3. Peristalsis 4. Acts a reservoir 5. Limited site of absorption C. Features of the Muscular layers and mucosal lining of the stomach 1. Smooth muscle layers of the stomach 2. Mucosa of the stomach (rugae) 3. Gastric canal D. Anatomy of the stomach 1. Anatomical regions of the stomach 2. Curvatures and notches of the stomach 3. Gastro/esophageal junction 4. Pyloric/duodenal junction E. Anatomical relationships of the stomach 1. Hepatogastric ligament (part of the lesser omentum) 2. Greater omentum 3. Thoracic diaphragm 4. Liver 5. Spleen 6. Transverse colon and the left colic flexure 7. Anterior abdominal wall 8. The bed of the stomach 9. Peritoneal attachments F. Arterial blood supply to the stomach 1. Left gastric artery 2. Splenic Artery 3. Common hepatic artery G. Venous drainage of the stomach H. Lymphatic drainage of the stomach I. Innervation of the stomach 1. Parasympathetic innervation 2. Sympathetic innervation 3. Pain and stretch sensory 4. The enteric nervous system II. The liver A. General functions of the liver B. Anatomy of the liver 1. Diaphragmatic surface of the liver 2. Suspension of the liver 3. Peritoneal recesses related to the liver 4. Visceral surface of the liver a. Right visceral lobe b. Left visceral lobe c. Caudate lobe d. quadrate lobe e. Defining the boundaries of the visceral surface C. Functional lobes of the liver Gross Anatomy: Stomach, Liver, Gallbladder Page 3 of 21 Dr. Dennis Goebel D. Blood supply to the liver Portal vein Proper hepatic artery E. Venous return of the liver III. Gallbladder A. Anatomy of the gallbladder B. Formation of the bile duct C. Function of the gallbladder 1. Concentration of bile 2. Release of bile D. Blood supply to the gallbladder 1. Origin and location of the cystic artery a. Defining the boundaries of the cystohepatic triangle b. Contents of the cystohepatic triangle E. Innervation of the gallbladder 1. Autonomic innervation a. Parasympathetic fibers b. sympathetic fibers 2. Visceral sensory a. Greater splanchnic nerve b. Right phrenic nerve IV. Clinical Aspects A. Stomach 1. Peptic ulcers 2. Gastric carcinoma 3. Hiatus hernia B. Liver 1. Intraperitoneal hemorrhaging 2. Metastatic carcinoma 3. Cirrhosis of the liver 4. Hepatitis 5. Jaundice C. Gallbladder 1. Gallstones Supplemental Reading: Gray’s Anatomy for Students, 3rd Ed (2015) Drake, Vogl, Mitchell. pp 310-311, 328-332. Gross Anatomy: Stomach, Liver, Gallbladder Page 4 of 21 Dr. Dennis Goebel Anatomy of the Stomach, Liver and Gallbladder I. STOMACH A. Definition: 1. Portion of Alimentary system that is positioned between the esophagus and duodenum B. Functions 1. Digestion of food by 2 mechanisms: chemical & mechanical 2. Stomach mucosa generates and releases hydrogen ions to maintain a pH of 2.0, and gastric enzymes (mainly pepsin), in aiding with the reduction of solid foods to a pulp- like liquid called chyme. 3. Peristaltic action of muscle fibers mixes food with digestive juices, facilitating reduction to chyme. 4. Acts as a reservoir, empty volume 50-75 ml, capable of accommodating up to 2-3 liters. 5. Site of “limited” absorption. C. Features of the muscular wall and mucosal lining of the stomach 1. Smooth muscle layers of the stomach (Figure 1) a. Outer layer: Longitudinal smooth muscle b. Middle layer: Circular smooth muscle c. Inner Layer: Oblique smooth muscle (Incomplete) Figure 1: N270a, c 2. Mucosa of the stomach rugae: Non-permanent folds of the mucosa that is prominent when the stomach is empty (Figure 1). When the stomach is distended (full), these folds flatten out and the mucosa appears smooth. 3. Gastric canal: In resting state, the inner volume of the stomach is greatly reduced (down to ~ 75 ml), however a permanent channel (called the gastric canal) remains in place to route liquids entering from the esophagus to the 1 st part of the duodenum, without expanding the stomach. See Figure 1. Gross Anatomy: Stomach, Liver, Gallbladder Page 5 of 21 Dr. Dennis Goebel D. Anatomy of Stomach: (See Figure 2) 1. Anatomical regions of the stomach: subdivided into 5 regions. a. Cardiac portion: connects to the esophagus. b. Fundus: usually filled with gas and in contact with the thoracic diaphragm. c. Body: the largest region of the five, and is responsible for the secretory part of the stomach. d. Pyloric antrum: transition from the body to the pyloric canal. e. Pyloric canal: terminal part of the stomach, that connects to the duodenum and ends as the pyloric sphincter. 2. Curvatures and notches of the stomach: The stomach has two curvatures. a. The lesser curvature, which is located along the superior margin of the stomach. It is associated with the lesser omentum. b. The greater curvature is located along the inferior/lateral margin of the stomach and is associated with the greater omentum and gastrosplenic ligament. c. Located between the junction of the cardiac and fundus of the stomach, there is a sharp indentation called the cardiac notch. d. A second (less-well defined) notch called the angular notch. It is located along the lesser curvature, and defines the boundary between the body and the pyloric regions (antrum and canal) of the stomach (See Figure 2). Gross Anatomy: Stomach, Liver, Gallbladder Page 6 of 21 Dr. Dennis Goebel 3. Gastro/esophageal junction: The transition from the Figure 3: N232a esophagus to cardiac portion of the stomach occurs at the level of TV10 and is defined anatomically as the point where the esophagus passes through the thoracic diaphragm. This junction is strengthened by the ascending and descending phrenoesophageal ligaments and thickening of fascia around the esophageal opening. Note, the terminal part of the esophagus contains a functional valve called the lower esophageal sphincter (Figure 3). 4. Pyloric/duodenal junction: Marks the location of a true smooth muscle valve called the pyloric sphincter. This valve is regulated by autonomics (e.g., sympathetic and parasympathetic) and controls the flow of digested food/liquid from the stomach into the duodenum (See Figure 1, on first page of notes). E. Anatomical relationships of the stomach (see Figure 2, previous page) 1. The hepatogastric ligament (part of the lesser omentum) extends from the visceral surface of the liver to the lesser curvature of the stomach. 2. The greater omentum is attached to the greater curvature of the stomach and drapes inferiorly to insert onto the transverse colon. 3. The thoracic diaphragm is in direct contact with the fundus region. 4. The liver (mostly left lobe) is superior to the body and pylorus. 5. The spleen is to the left of the body of the stomach. 6. The transverse colon and the left colic flexure (aka splenic flexure) are located inferior/posterior to the body of the stomach. 7. The anterior abdominal wall is anterior to the stomach. 8. The bed of the stomach: (posterior to the stomach) Formed by the posterior wall of the omental bursa (lesser sac). Retroperitoneal structures within bed include the pancreas, left kidney, left adrenal gland, diaphragm (part), celiac artery (trunk and proximal branches), splenic artery and splenic vein, terminal part of the superior mesenteric artery & vein. In addition, peritoneal structures including the spleen and the transverse colon make up part of the bed of the stomach (See Figure 4 on the next page). Gross Anatomy: Stomach, Liver, Gallbladder Page 7 of 21 Dr. Dennis Goebel 9. Peritoneal attachments (Figure 4): The stomach, although motile and extensible in the body region, is firmly anchored to the diaphragm and posterior abdominal wall in the region of the fundus and superior lateral aspect of the greater curvature by peritoneal ligaments. These ligaments are named by the regions they span. a. Attaching to the lateral (left) surface of the cardiac portion of the stomach and following the posterior-superior and lateral margin of the fundus and inserting onto the left diaphragm is the gastrophrenic ligament. b. The same two sheets of peritoneum then course along the posterior-lateral margin of the greater curvature of the stomach just medial to the spleen. The ligament from the spleen to the greater curvature of the stomach is called the gastrosplenic ligament (Figure 4). c. The same two sheets of peritoneum making up the gastrosplenic ligament continues to the posterior body wall and attaches to it immediately anterior to the left kidney and is called the splenorenal ligament (Figure 4). The splenorenal ligament contains the terminal branches of the splenic artery and returning veins (more on this below), as well as containing the tail of the pancreas. d. The hepaticduodenal ligament (See Figure 2 on second page of notes), which attaches the superior region of the first part of the duodenum to the liver, maintains the positioning of the pyloric region of the stomach. The hepaticduodenal ligament invests the hepatic portal vein, the hepatic duct, cystic duct and bile duct, along with the proper hepatic, the right and left hepatic and the cystic arteries (see Figure 5 on the next page). Figure 4:N266 Gross Anatomy: Stomach, Liver, Gallbladder Page 8 of 21 Dr. Dennis Goebel Figure 5:N278a F. Arterial blood supply to the stomach: The primary source of arterial flow to the stomach is provided by the celiac trunk (one of three single midline abdominal arteries that supply the viscera). The celiac trunk is located just inferior to the crura of the diaphragm at the level of TV12, and gives rise to 3 primary branches (left gastric, splenic and common hepatic arteries). All three arteries provide direct supply to the stomach (Figure 6 on the next page). 1. The LEFT GASTRIC ARTERY (Figure 6) supplies the left half of the lesser curvature of the stomach and gives rise to an ascending esophageal branch, which anastomose with thoracic esophageal arteries (see Figure 7) to supply the cardiac region of the stomach. In the lesser curvature, it forms an anastomosis with the right gastric artery (a branch off of the proper hepatic artery; see below) within the lesser omentum. 2. The SPLENIC ARTERY (Figure 6 on next page) is a very torturous artery that can be found embedded in the posterior abdominal wall just superior to the superior margin of the body of the pancreas. It gives rise to several branches to the pancreas (covered in a later lecture), in-route to the spleen. Approaching the spleen, the splenic artery enters the splenorenal ligament and branches into 5-7 splenic branches that go directly to the spleen, and provides 2-3 short gastric arteries, which supply the fundus of the stomach. It also gives off a single left gastro- omental artery (also known as the left gastroepiploic), which courses within the greater omentum to supply the left half of greater curvature of the stomach. The left gastro-omental artery forms an anastomosis with the right gastro-omental artery (Figure 6 on next page) origin and course is describe below. Gross Anatomy: Stomach, Liver, Gallbladder Page 9 of 21 Dr. Dennis Goebel Figure 6: N283 Figure 7: N283 (4th Ed) 3. The COMMON HEPATIC ARTERY is positioned to the right of the left gastric and splenic arteries and gives rise to two major branches, the proper hepatic and gastroduodenal arteries. The proper hepatic artery usually gives of the right gastric artery (as its first branch), which supplies the right half of the lesser curvature of the stomach and the pyloric region. The rt. gastric artery forms an Gross Anatomy: Stomach, Liver, Gallbladder Page 10 of 21 Dr. Dennis Goebel anastomotic connection with the left gastric artery. The proper hepatic artery continues to supply the liver and gallbladder (more on this below). The second branch of the common hepatic artery is the gastroduodenal artery. This artery descends posterior to the junction of the pylorus and the duodenum and gives rise to two major branches, the right gastro-omental (also known as the rt gastroepiploic) and the superior pancreaticoduodenal artery (to be covered in a future lecture). The right gastro-omental artery supplies the right half of the greater curvature of the stomach and forms an anastomotic connection with the left gastro-omental artery (a branch of the splenic artery) within the greater omentum (Figure 6). G. Venous drainage of the stomach (Figure 8 on next page): Venous return from all organs associated with the digestive track (distal to the esophagus and proximal to the anal canal) is directed to the liver via the hepatic portal vein. The portal vein is formed by the junction of the splenic vein and the superior mesenteric vein and travels within the hepatoduodenal ligament in route to the liver (more on this below). 1. The veins of the stomach are named to their corresponding arteries and drain into the hepatic portal system as follows. a. The left gastro-omental vein and the short gastric veins usually drain directly into the splenic vein (Figure 8). b. The right and left gastric veins usually drain directly into the portal vein. See Figure 7. c. The right gastro-omental vein usually empties into the superior mesenteric vein (see Figure 8). Figure 8: N289a Gross Anatomy: Stomach, Liver, Gallbladder Page 11 of 21 Dr. Dennis Goebel H. Lymphatic drainage of the stomach. Lymph nodes follow the arterial pathways to the stomach and are named by the corresponding artery. All lymph nodes drain directly into the celiac lymph nodes, which clustered around the celiac trunk and then drain into the thoracic duct. I. Innervation of the stomach: Autonomics (Sympathetic and Parasympathetic) provide motor and secretory input to the stomach. 1. Parasympathetic input is provided by the vagus N [X] primarily by the anterior vagal trunk (Figure 9). These preganglionic fibers act locally to increases glandular secretions (Hydrogen ion & pepsinogen), stimulates peristalsis of the stomach and dilates the pyloric sphincter. 2. Sympathetic innervation is primarily provided post-ganglionic fibers from the celiac ganglion (paired). Preganglionic fibers are from the greater splanchnic nerve (TN5- TN9). Sympathetic innervation: reduces peristalsis, glandular secretion and constricts the pyloric sphincter (See Figure 9). 3. Pain and stretch sensory fibers use the sympathetic pathway by way of the greater splanchnic nerve to transmit their signals from the stomach to dermatome levels corresponding to T5-T9. The cell bodies of these sensory neurons are housed in the dorsal root ganglion at these thoracic levels (See Figure 9). 4. The enteric nervous system: is an endogenous neuronal network that travels the full extent of the alimentary tract (esophagus-rectum). Although regulated by both parasympathetic and sympathetic input, the enteric nervous system can function independently to provide low-level glandular secretion and auto-peristalsis. Figure 9: N398 Gross Anatomy: Stomach, Liver, Gallbladder Page 12 of 21 Dr. Dennis Goebel II. The LIVER A. General functions of the liver: The liver is the largest and most vascularized organ in the body. It functions as the primary site for detoxification and intermediary metabolism. The liver is a major storage site for glycogen and is responsible for the synthesis of bile, proteins, and cholesterol. It also is involved with the process of retiring senescent blood cells by reclaiming iron, and is a major lymph-producing organ (produces over half of the lymph entering the thoracic duct). B. Anatomy: The liver lies mostly in the upper right quadrant of the abdominal cavity and is completely hidden by the thoracic cage and diaphragm. It is found deep to the ribs (7-10) and its sharp inferior border follows the contour of the right costal margin. The liver has two surfaces, (diaphragmatic and visceral) (Figures 10 & Figure 11). 1. The diaphragmatic surface has a smooth-contoured surface that is directly related to the thoracic diaphragm. It is divided at midline by the falciform ligament (on its ventral surface) into right and left anatomical lobes (Figure 10). Figure 10: N277a A B Figure 11: N277c & d Gross Anatomy: Stomach, Liver, Gallbladder Page 13 of 21 Dr. Dennis Goebel 2. Suspension of the liver: The liver is suspended superiorly from the thoracic diaphragm by the anterior & posterior coronary and right. & left triangular ligaments (See Figures 10 & 11 on previous page). The anterior and posterior coronary ligaments are continuous with the falciform ligament and are all derived from the ventral mesogastrum. Due to the rapid growth of the liver during development, the mesentery sheets that make up the ventral mesogastrum were separated and pulled away from a portion of the liver and diaphragm to create the anterior and posterior (see Figures 9 & 10) coronary ligaments. The sharp transitions between the anterior and posterior ligaments are called the right and left triangular ligaments. Together, all four ligaments suspend the liver from the thoracic diaphragm. a. The separation of the coronary ligaments by the growth of the liver creates an area on the superior diaphragmatic surface of the liver, and the corresponding region of the inferior surface of the thoracic diaphragm, which is void of peritoneal covering. This is referred to as the bare area of the liver (Figure 11A) and diaphragm (Figure 11B) respectively. Note that this area is bounded by the right and left triangular and anterior & posterior coronary ligaments and is the site where the hepatic veins of the liver (usually 2-3, see Figure 11A) empty into the inferior vena cava (See Figure 11B). b. Peritoneal Recesses related to the liver: The attachment of the liver to the diaphragm via the coronary/ triangular ligaments creates two peritoneal recesses that are potential sites for fluid accumulation. i. Ventral to the anterior coronary ligament is the subphrenic recess (Figure 12). ii. Dorsal/inferior to the posterior coronary ligament is the hepatorenal recess (See Figure 12). Ant. Coronary lig Ventral Post. Coronary lig. Moore, Fig. 2-65 Figure 12: Moore 2-65 3. The visceral surface of the liver is located on the inferior aspect of the liver. This surface is related to the gallbladder, stomach and first-part of the duodenum (e.g. the viscera). A series of ligaments subdivide the visceral surface of the liver into 4 lobes (Figure 13 on next page). Gross Anatomy: Stomach, Liver, Gallbladder Page 14 of 21 Dr. Dennis Goebel 4. Visceral lobes of the liver a. Right visceral lobe b. Left visceral lobe c. Caudate lobe d. Quadrate lobe Note that the right anatomical lobe, as view from the diaphragmatic surface (Figure 13A), is formed from the right visceral lobe, and from the quadrate and caudate lobes (Figure 12 B); whereas, the left anatomical lobe, as view from the diaphragmatic surface (Figure 13A), corresponds to the left visceral lobe (see Figure 13B). A B Figure 13: N277a &b e. Defining the boundaries of the 4 visceral lobes on the visceral surface of the liver: The ligamentum teres (invested by the falciform ligament) and the ligamentum venosum, together with the positioning of the gallbladder and the inferior vena cava forms the two vertical arms of the letter “H”; and the porta hepatis (defined as the site where the rt. & left-portal veins, -hepatic arteries and -hepatic ducts enter and leave the liver) forms the horizontal bar of the letter “H”. These anatomical features provide the boundaries of the four visceral lobes of the liver (Figure 14 on the next page). Gross Anatomy: Stomach, Liver, Gallbladder Page 15 of 21 Dr. Dennis Goebel i. The Ligamentum teres (embryological remnant of the umbilical vein that is embedded in the free margin of the falciform ligament), together with the ligamentum venosum (embryological remnant of ductus venosus) separate the left visceral lobe from the caudate and quadrate lobes. (See Figures 13 &14). ii. The porta hepatis ("the door to the liver”) separates the quadrate lobe (ventral to the porta hepatis) from the caudate lobe (dorsal to the porta hepatis), see Figure 13. iii. The gallbladder (and its corresponding fossa) and the cystic duct, together with the inferior vena cava, separates the right visceral lobe from the quadrate and caudate lobes on the visceral surface (See Figures 13 &14). Figure 14: N277b (modified) C. The functional divisions of the liver: There are eight functional lobes in the liver, as determined by branches of the arterial, portal vein and hepatic duct branches. These are collectively known histologically as the “triad”; (Figure 15 on the next page). Note, the venous drainage from the liver via the hepatic veins, are not part of the liver triad (See Figure 14 above). Gross Anatomy: Stomach, Liver, Gallbladder Page 16 of 21 Dr. Dennis Goebel Figure15 D. Blood supply to the liver is provided by the hepatic portal vein and the proper hepatic artery. (See Figure 6 on page 9 of my notes, and Figure 13 on the previous page). 1. The Portal vein contains rich in nutrients, via uptake by the small intestines, while still maintaining a relatively high oxygen tension, compared with blood returning via the systemic system (e.g. vena cava). The portal vein divides into a right and left hepatic portal branch upon entering the porta hepatis. 2. The proper hepatic artery (See Figure 6 on page 6 of my notes) brings oxygen-rich blood to the liver. It is a branch of the common hepatic artery & divides into a right and left hepatic artery at the porta hepatis (Figures 14 & 15). Note, the portal vein, proper hepatic artery and the hepatic duct travel together and form the portal triad. E. Venous return of the liver is provided by the hepatic veins. The hepatic veins (usually 3 of them) are not part of the portal triad, but instead exit the liver (on its diaphragmatic surface) directly into the inferior vena cava (See Figure 16 on the next page). Gross Anatomy: Stomach, Liver, Gallbladder Page 17 of 21 Dr. Dennis Goebel Figure 16: N 277C & D GALLBLADDER (Figure 13A &B and Figure 17): The gallbladder is a smooth muscular sac that is responsible for the concentration and storage of bile. This organ contracts and injects the bile into the 2nd part of the duodenum, via the common bile duct. It is located in the gallbladder fossa on the visceral surface of the liver, between the right and quadrate lobes. The fundus of the gallbladder is related (rests directly on) to the 1 st part of the duodenum (Figure 17) and is in direct contact with the anterior abdominal wall (at the costal margin). A. Anatomy of the gallbladder: The gallbladder consists of a fundus, body and neck that empties into the cystic duct (see Figure 17). The internal surface of the cystic duct forms a spiral path (Figure 17), and although it is called the spiral valve, it is not a functional valve. B. Formation of the (common) bile duct: The cystic duct of the gallbladder joins the common hepatic duct of the liver to form the Duodenum (common) bile duct. (descending part) 1. Pathway of the bile Hepatopancreatic ampulla duct: The bile duct Major duodenal papilla descends within the hepatoduodenal Figure 17: N280b ligament and is Gross Anatomy: Stomach, Liver, Gallbladder Page 18 of 21 Dr. Dennis Goebel positioned anterior to the portal vein, and lateral to the proper hepatic artery. It passed posterior to the first part of the duodenum, enroute to the descending part of the duodenum (2nd part) where it meets with the main pancreatic duct, prior to entering the descending part of the duodenum on its posterior-medial wall. Details will be described in a future enrichment presentation. At the distal end of the bile duct, there is a smooth muscle valve called the bile duct sphincter, which is normally closed until ingestion of fatty foods (Figure 17 on previous page). C. Function of the gallbladder (GB): 1. Concentration of bile: Bile produced by the liver is relatively dilute upon entering the hepatic duct and requires concentration by the gallbladder. The closed bile duct sphincter located at the terminal end of the bile duct (Figure 17), allows the flow of the dilute bile to back up into the gallbladder, where it is then concentrated, by re- absorption of water and essential metabolites, by its mucosa. 2. Release of bile: Upon contraction of the GB, the concentrated bile mixes with the release of pancreatic enzymes, and then pass through the sphincter of hepatopancreatic ampulla , (located in the medial wall of the 2nd part of the duodenum) into the duodenum. This opening is visible in the medial wall of the duodenal mucosa and appears as a raised mound, usually covered by the circular folds of the duodenal mucosa, and is called the major duodenal papilla (Figure 17 on previous page). More on this in a subsequent enrichment presentation. D. Blood supply to the gallbladder: 1. The gallbladder is supplied by the cystic artery, which is usually given off by the right hepatic artery. The cystic artery usually passes posterior to the common hepatic duct, within the hepatoduodenal ligament, in route to the neck of the gallbladder. This region is of surgical importance and is known as the cystohepatic triangle (Figure 18). a. Boundaries of the cysto-hepatic triangle are: i. Common hepatic duct medially ii. Cystic duct laterally iii.Liver superiorly. b. The contents of the triangle include the cystic artery & vein, and the right hepatic artery. Figure 18: N384 Gross Anatomy: Stomach, Liver, Gallbladder Page 19 of 21 Dr. Dennis Goebel E. Innervation of the gallbladder: 1. Autonomic innervation: a. Parasympathetic fibers derived from the vagus N (X) participates in facilitating contraction of the gallbladder, along with endocrine release of CCK. b. Sympathetic fibers are supplied by postganglionic fibers from the celiac ganglion which receives preganglionic input from the greater splanchnic nerve. Function to relax the contraction of the gallbladder. 2. Visceral sensory (pain) of the gallbladder is relayed by via the greater splanchnic nerve and right phrenic nerves. a. Greater splanchnic nerve: Visceral pain is referred to the rt thoracic wall corresponding to dermatomes T7-T9 to an area of skin spanning from the rt spinous process of vertebrae T-7-T9 and projecting around to the epigastric region on the anterior abdominal wall (See Figure 19). b. Phrenic N. (Cervical N’s C3-5): Visceral pain relayed from the gallbladder is relayed to the right shoulder blade via the right phrenic N. (See Figure 19). Common Areas of Referred Pain in Liver and Biliary Disease C3,4,5 R. Phrenic N. T7,8,9 (Greater Splanchnic) T10 Figure 19: N306 Gross Anatomy: Stomach, Liver, Gallbladder Page 20 of 21 Dr. Dennis Goebel IV. CLINICAL ASPECTS A. Stomach: 1. Site of peptic ulcers are usually found on the posterior wall of the mucosal of the stomach (Figures 20 a &b). If sever, whereby the mucosa and underlying muscle layers have undergone digestive erosion, (defined as a penetrating ulcer, Figure 18b), underlying structures associated with the “bed of the stomach” are vulnerable to digestive erosion as well. Recall that the posterior wall of the stomach rests directly upon the body of the pancreas. Digestive erosion of this organ via a penetrating ulcer, is a medical emergency and often fatal. Figure 20 A B Figure 20: Endoscopy images of the posterior wall of the stomach showing examples of gastric mucosal ulcers that are defined as non-penetrating (A) and fully penetrating (B). Images were obtained from the North American Society for Pediatric Gastoenterology Hepatology and Nutrition (naspghan.org). 2. Gastric carcinoma: Develops from mutated gastric mucosa epithelium and is a highly aggressive form of cancer. According to the American Cancer Society the most common causative in triggering gastric carcinoma is from and infection resulting from the bacterium hemicobacter pylori. Current 5 year survival rate for gastric carcinoma is ~10%. 3. Hiatus hernia: Where a portion of the stomach is pulled through the esophageal hiatus and displaced into the thoracic cavity (see Figure 21). Figure Moore,21: FigMoore 2-37A Fig & B2-37 Gross Anatomy: Stomach, Liver, Gallbladder Page 21 of 21 Dr. Dennis Goebel B. Liver: 1. Rupture of the liver results in intraperitoneal bleeding (potentially fatal). 2. A major site of metastatic carcinoma. 3. Cirrhosis commonly caused by excessive alcohol or drug use results in progressive destruction of hepatocytes. Over time, this can lead to liver failure. 4. Hepatitis is defined as an inflammation of liver that is usually caused by viral infection or from chemical toxins. 5. Jaundice: An elevated level of bile pigment found in the blood stream causes a yellow appearance in the skin and conjunctiva of the eyes. One of the possible causes for this pathology would be the blockage of the bile duct system by a gallstone. This blockage causes bile to back up into the liver and prevents further processing of the bile pigment (bilirubin) from the blood. 6. Liver regeneration: The liver is the only visceral organ capable of regeneration. Surgical removal of a diseased lobe of the liver signals the healthy liver tissue to regenerate through activation of a series of growth factors. This unique characteristic has been applied to liver transplantations, whereby a portion of the matched-donor’s healthy liver can be transplanted into a patient whose diseased liver has been removed. Both the donor’s and the recipient’s transplanted liver will rapidly regenerate and remodel the respective livers to their original mass, but not to their lobular shapes. See Figure 15. C. Gallbladder: 1. Gallstones can produce blockage of bile. They can be found throughout the bile- duct system. Most common site of blockage occurs in the hepatic-pancreatic ampulla (terminal part of the bile and the pancreatic ducts). Besides being extremely painful, full blockage of the bile duct can case bile to build up within the liver and cause jaundice (see above). Sources for Figures in the notes: Gardner, Gray and O'Rahilly, Anatomy 4th Edition, W.B. Saunders Co., Philadelphia, © 1975. Mizeres, Human Anatomy: A Synoptic Approach, Elsevier, New York, © 1981. Moore, Clinically Oriented Anatomy, 3rd Edition, Williams & Willkens, Baltimore, © 1992. Netter, Atlas of Human Anatomy, 6th Ed., Saunders, Philadelphia, © 2014. North American Society for Pediatric Gastoenterology Hepatology and Nutrition (naspghan.org).