W2 Workshop: Gross Anatomy of the Liver, Gallbladder, Biliary Tree, Pancreas and Spleen PDF

GINU4001-10915  Fusion Session | Workshop: Gross Anatomy of the Liver, Gallbladder,  Biliary Tree, Pancreas and Spleen             ...

GINU4001-10915  Fusion Session | Workshop: Gross Anatomy of the Liver, Gallbladder,  Biliary Tree, Pancreas and Spleen                     Fusion Session | Workshop: Gross Anatomy of the Liver, Gallbladder, Biliary Tree, Pancreas and Spleen  How to Approach Fusion Sessions Purpose of Fusion Sessions Fusion sessions are online learning activities followed by a live session where you will translate the content into practice. These require completing learning content in Canvas before attending live sessions. To encourage preparation, attendance, and participation, recordings of fusion sessions will not be posted; prepare accordingly so that you can fully participate. Remember: Learning from written materials is a critical professional and personal skill that RUSM is helping you develop through these sessions. Suggested Process 1. Work through the content on this page. 2. Contact faculty via email or office hours if you have questions about content to ensure you are prepared for the session. 3. Take the quiz. (You have three attempts.) 4. Attend and participate in the live session. 5. Take the quiz again. 6. Study missed content. 7. Take the quiz for the final attempt. Listen  Overview The upcoming workshop will encompass a comprehensive exploration of the gross anatomy and neurovasculature pertaining to the accessory organs of the gastrointestinal tract and the spleen. Delving into intricate details, we will dissect the anatomical nuances of the liver, gallbladder, pancreas, biliary tree, and spleen, elucidating their structural organization and clinical significance. Through this interactive session, students will gain a profound understanding of the intricate networks of blood vessels and neural pathways that supply these vital organs, offering invaluable insights into their clinical relevance. Learning Objectives By the end of this session, you will be able to meet the following learning objectives: 1. Describe the gross anatomy of the liver including the anatomic vs functional lobes, ligaments, neurovasculature and lymphatic drainage. 2. Identify the surfaces of the liver and their characteristic features. 3. Correlate liver anatomy to the clinical conditions in the lecture. 4. Describe the gross anatomy of the gallbladder, biliary tree and pancreas including the parts, neurovasculature and lymphatic drainage of each organ. 5. Identify the boundaries of the cystohepatic triangle (a.k.a. Triangle of Calot). 6. Correlate gallbladder, biliary tree and pancreas anatomy to the clinical conditions in the lecture. 7. Describe the gross anatomy of the spleen including closely related structures, the neurovasculature and lymphatic drainage. 8. Correlate the gross anatomy of the spleen to the clinical conditions in the lecture.  Introduction In the intricate landscape of human anatomy, the accessory organs of the gastrointestinal (GI) tract and the spleen stand as crucial players in the orchestration of digestive and immune functions. While the spleen may not be directly integrated into the gastrointestinal system, its close anatomical proximity and shared blood supply necessitate its inclusion in this discussion. The liver, gallbladder, pancreas, biliary tree, and spleen form an interconnected network that harmonizes digestive processes, regulates metabolism, and fortifies immune defenses. Let’s start our exploration of the accessory organs.  First up: The Liver! The liver is the largest internal organ in the human body. It is a multifunctional powerhouse located intraperitoneally in the right and left upper quadrants of the abdomen. Its distinctive lobular structure and rich blood supply serve as a vital hub for numerous metabolic, synthetic, and detoxification processes essential for maintaining homeostasis. From filtering blood, metabolizing nutrients, and producing bile for digestion to storing glycogen, synthesizing proteins, and detoxifying harmful substances, the liver plays an indispensable role in sustaining overall health and vitality. Its intricate architecture and diverse array of functions underscore its status as a cornerstone of physiological well-being, making it indispensable for the body's myriad metabolic and regulatory processes. Let’s take a closer look at the gross anatomy of the liver! Click on the tabs below to learn more about the surfaces, lobes, segments, and ligaments of the liver. Surfaces of the Liver Lobes of the Liver Segments of the Liver Ligaments of the Liver The liver is distinguished by specific borders and surfaces. Its superior border is in contact with the diaphragm, while its inferior border sits on the hepatic flexure of the colon and the right kidney. Anteriorly, it is adjacent to the anterior abdominal wall. Regarding surfaces, the liver boasts a diaphragmatic or antero-superior surface, which faces the diaphragm, and a visceral surface or postero-inferior surface that rests upon the inferior vena cava, gallbladder, and right kidney. The postero-inferior surface has depressions or fossae for the inferior vena cava and gallbladder and is, therefore, noticeably distinguishable from the antero-superior surface. The porta hepatis is also visible only on the postero-inferior surface of the liver. The porta hepatis (hilum) is the entrance and exit of the liver for several important structures. It consists of the hepatic artery proper, the hepatic portal vein, and the common bile duct, which are arranged duct, artery, and vein anteriorly to posteriorly. Image Transcript   Next up: The Gallbladder and Biliary Tree! The gallbladder is an intraperitoneal organ attached to the undersurface of the liver by the cystic duct. It stores and concentrates bile, a green fluid produced by the liver, that assists in the emulsification of fats. Bile produced by the liver exits the liver via the right and left hepatic ducts which unite to form the common hepatic duct. The common hepatic duct is joined by the cystic duct to form the common bile duct which opens into the duodenum at the Ampulla of Vater. When the sphincter of the bile duct (Sphincter of Oddi) is closed, bile flows backward along the common bile duct into the cystic duct to be stored in the gallbladder. The gallbladder can hold up to 50ml of bile, which undergoes concentration due to the absorption of water and salts. When a fatty meal is ingested, various hormones are released, which results in the contraction of the gallbladder and relaxation of the sphincter to expel bile through the cystic duct back into the common bile duct, which continues on to join the main pancreatic duct and open into the Ampulla of Vater (major duodenal papilla) in the duodenum. This interconnection of ducts to transport bile from the liver to the duodenum is known as the biliary tree. Image Credit: Adtalem Glodal Education Image Transcript: right hepatic duct, cystic duct, neck of gallbladder, body, pancreatic duct, common bile duct, common hepatic duct, left hepatic duct Parts of the Gallbladder Now, let’s discuss the anatomy of the gallbladder itself. The gallbladder has three parts. Click through the interactive below to learn more about the three parts of the gallbladder.INSERt HERE Parts of the Gallbladder + + + Transcript  Clinical Correlate of the Gallbladder Image Transcript  Cholelithiasis refers to the formation of small, solid, stone-like deposits in the gallbladder. It's relatively common in females and often presents without symptoms. However, when symptoms do occur, they may include pain in the right upper quadrant (RUQ) of the abdomen, which can sometimes radiate to the right neck or shoulder region, as well as nausea. In cases where cholelithiasis leads to inflammation of the gallbladder, known as cholecystitis, symptoms may also include jaundice due to obstruction of either the major duodenal papilla or the common bile duct. The hepatopancreatic ampulla is a common constriction site where gallstones often become painfully lodged. Cholecystectomy is a surgical procedure aimed at removing the gallbladder. Since the gallbladder is not a vital organ, individuals facing a high risk of gallstone recurrence or experiencing frequent episodes of severe biliary colic may opt for this procedure to alleviate symptoms by eliminating the source of the problem. Dissection of the cystohepatic triangle or Triangle of Calot is considered crucial for safely conducting a laparoscopic cholecystectomy. This triangular area is defined by specific anatomical landmarks: the cystic duct, the common hepatic duct, and the inferior margin of the liver. This helps in assessing any variations in the cystic artery or biliary apparatus. Once identified, the cystic duct and cystic artery are carefully ligated and divided to prevent bleeding and the inadvertent release of bile. The boundaries of the cystohepatic triangle are: 1. Superior boundary: Inferior border of the liver (dark purple line) 2. Medial boundary: Common hepatic duct (yellow line) 3. Lateral boundary: Cystic duct (green line) Review the image below to review the boundaries of the cystohepatic triangle. Triangle of Calot  Next: The Pancreas! The pancreas is an abdominal organ that boasts two distinct tissue types with complementary functions. Acting as an exocrine gland, it secretes substances through ducts onto epithelial surfaces. Simultaneously, as an endocrine gland, it releases hormones into the bloodstream. These dual roles synergistically regulate food breakdown and its absorption by peripheral tissues. The exocrine pancreas produces enzymes facilitating nutrient absorption in the small intestine by breaking down food into basic building blocks. Conversely, the endocrine pancreas releases regulatory hormones, prompting tissues to extract nutrients from the blood. Situated in the retroperitoneal cavity near the L1-L2 vertebrae within the upper abdomen, it occupies the epigastric and left hypochondriac regions along the posterior abdominal wall, protected by the rib cage. Due to its horizontal orientation, it's challenging to palpate or damage, though severe penetrating or blunt traumas can cause injury. Image Credit: ScholarRx Anatomy and Histology of the Pancreas Image Transcript  Parts of the Pancreas The pancreas is anatomically divided into four main parts: the head, neck, body, and tail. Click through the interactive below to learn more about the head, neck, body, and tail of the pancreas. Parts of the Pancreas + + + + Transcript  Ducts of the Pancreas The pancreas is associated with two important ducts: the main pancreatic duct and the common bile duct. The main pancreatic duct transports digestive enzymes from the pancreas to the duodenum, opening at the ampulla of Vater. Conversely, the common bile duct conveys bile from the liver and gallbladder to the duodenum, also connecting at the ampulla of Vater. Additionally, there is an accessory pancreatic duct, known as the duct of Santorini (which is not present in all individuals), and opens into the gastrointestinal tract via the minor duodenal papilla, often communicating with the main pancreatic duct. Anatomy and Histology of the Pancreas. Image Credit: ScholarRx Image Transcript  Clinical Correlates of the Pancreas Pancreatic cancer occurring in the head of the pancreas is the most frequent location for this disease. Tumors in this area have the potential to block the common bile duct and the hepatopancreatic ampulla (Ampulla of Vater). Such obstruction can lead to jaundice, which is the yellowing of the skin and sclera due to the retention of bile pigments. It also results in pale or grey-colored stools. Conversely, cancer affecting the neck and body of the pancreas may obstruct the hepatic portal vein and the inferior vena cava. Image Transcript  Annular pancreas is a condition where a bifid ventral pancreatic bud rotates around the duodenum, one rotating clockwise, the other anticlockwise, thereby creating a ring of pancreas encircling the duodenum. This can result in partial or complete obstruction of the duodenum. It's often linked with polyhydramnios and Down syndrome (Trisomy 21). Symptoms typically manifest shortly after birth, characterized by vomiting stained with bile.  Lastly, The Spleen! While not a part of the gastrointestinal system, the spleen maintains close relations and a similar blood supply to organs within it. It has an ovoid shape and typically appears as a "pulpy" mass in the abdomen's left upper quadrant (LUQ), lying along the midaxillary line as an intraperitoneal organ. Functionally, it serves as the largest lymphatic organ in the body, capable of significant expansion and relatively rapid contraction. Acting as a blood reservoir, it plays a crucial role in identifying, removing, and destroying old red blood cells (RBCs), as well as recycling iron and globin. Although not considered a vital organ, it is highly vulnerable, especially due to its close relationship with the ribs. Anatomically, it shares close connections with various structures: anteriorly with the stomach, posterolaterally with the left dome of the diaphragm and ribs 9, 10, and 11, medially with the left colic flexure, and inferiorly with the left kidney and the tail of the pancreas, through which the splenic artery travels in the splenorenal ligament. Surfaces of the Spleen The spleen possesses two distinct surfaces: the diaphragmatic surface and the visceral surface. The diaphragmatic surface of the spleen is the posterior aspect that lies adjacent to the diaphragm. This surface is relatively smooth and convex, conforming to the curvature of the diaphragm. It is positioned against the posterior abdominal wall, particularly the left dome of the diaphragm, and is partially covered by the ribs. On the other hand, the visceral surface of the spleen faces inward toward the abdominal cavity, where it comes into contact with various neighboring organs. This surface is irregular in shape, with multiple indentations and impressions caused by its close proximity to surrounding structures such as the stomach, left kidney, left colic flexure of the colon, and tail of the pancreas. Additionally, blood vessels and ligaments, including the splenic artery and vein, as well as the splenorenal ligament, are attached to the visceral surface of the spleen. Image Credit: 3.18 Spleen. In: Schünke M, Schulte E, Schumacher U, Voll M, Wesker K, Cass W, ed. THIEME Atlas of Anatomy, Volume 2: Internal Organs. 3rd Edition. New York: Thieme; 2020. doi:10.1055/b-000-000141 Image Transcript  Clinical Correlation of the Spleen The spleen stands as the most frequently injured abdominal organ. Despite the protection offered by the rib cage, a forceful impact to the left side can lead to rib fractures, causing bone fragments to puncture the spleen. An example of this scenario could involve impaction against the steering wheel during a road traffic accident. If the spleen ruptures, serious consequences ensue, including shock and profuse internal bleeding, known as intraperitoneal hemorrhage. In such cases, a splenectomy, the surgical removal of the spleen, becomes necessary to prevent death from bleeding. Splenomegaly, characterized by pathological enlargement of the spleen up to ten times its normal size, can also occur and is at high risk of splenic rupture. Additionally, individuals who have undergone splenectomy require vaccination against encapsulated organisms to mitigate the risk of infection. Note  One more thing before our session: watch this brief video on the arterial supply of the gastrointestinal system: Gastrointestinal Arteries for the USMLE Step 1 (11:56) During our session, we will delve into these organs' neurovasculature and lymphatic drainage.  Supplemental Information Neurovasculature and Lymphatics of the GI Organs (PDF)  Quiz Quiz | Gross Anatomy of the Liver, Gallbladder, Biliary Tree, Pancreas and Spleen  Contact Dr. Asha Eastmond Email: [email protected] Top Previous Next