Anatomy Quiz: Abdomen and Organs

Abdomen Anatomy 3 Lecture Notes

• Course: Block 1.2, 2024-2025
• Writer: Alaa Alessa
• Reviewer: Ghassan Al-Nasser
• Notes: 221-222-223
• Learning Outcomes: Students should be able to describe abdominal organs, understand their position/parts, and neurovascular supply.
• Contents: Included organs are Spleen, Pancreas, Liver, Gallbladder and Biliary system, Kidneys, Ureter, and Suprarenal gland.

Abdominal Regions

• Regions: The abdomen is divided into nine regions (Right Hypochondriac, Epigastric, Left Hypochondriac, Right Lumbar, Umbilical, Left Lumbar, Right Iliac, Hypogastric, Left Iliac).
• Organ Locations: Specific organs are detailed within respective regions (e.g., Liver, Gallbladder and Small Intestine are in the Right Hypochondriac region).

The Spleen

• Shape and Size: An ovoid, purplish, pulpy mass roughly the size of a fist.
• Location: Located in the superolateral part of the left upper quadrant (LUQ), protected by the inferior thoracic cage.
• Vulnerability: Considered the most vulnerable abdominal organ due to high vascularization. Injury can cause internal bleeding.
• Positioning: Posteriorly to the diaphragm, anteriorly to the stomach, inferiorly to the left colic flexure, and medially to the left kidney.
• Dimensions: Approximately 12cm long, 7cm wide, and 1 inch thick, weighing about 7 ounces.

Splenic Relations and Vessels

• Posterior: Separated from pleura, lung, and ribs 9-11 by the diaphragm.
• Anterior: Located near the stomach bed.
• Inferior: Near the left colic flexure.
• Medial: Touches the left kidney.
• Vessels: Blood vessels (artery and vein), lymphatics, and innervation enter/exit through the hilum.

Splenic Structure

• Capsule: The highly vascular spleen is covered by a fibrous capsule.
• Trabeculae: These are supporting structures extending from the capsule into the spleen.
• Pulp: The inside of the spleen is characterized by red pulp and white pulp.

Blood Supply of the Spleen

• Arterial: The splenic artery branches from the celiac trunk and is the main artery supplying the spleen.
• Venous: Splenic vein, formed from tributaries exiting the hilum, runs posterior to the body and tail of the pancreas, joining the superior mesenteric vein posterior to the neck of the pancreas to form the hepatic portal vein
• Venous Drainage: Splenic vein is crucial in the hepatic portal system and plays a role in nutrient transportation to the liver.

Splenic Lymphatic and Nervous innervation

• Lymphatic: Splenic lymphatic vessels exit the spleen at the hilum and connect to pancreaticosplenic and celiac lymph nodes ultimately connecting with the thoracic duct.
• Nervous: The spleen's nerves originate from the celiac plexus and the branches from the splenic artery, having vasomotor functions.

Pancreas

• Location: Retroperitoneal, spanning the transpyloric plane on the posterior abdominal wall. Lies posterior to the stomach and between the duodenum (right) and spleen (left).
• Structure: Has a head, neck, body, and tail and both endocrine and exocrine functions.
• Endocrine: Islets of Langerhans produce hormones like insulin and glucagon.
• Exocrine: The majority of the pancreas produces enzymes for digestion.

Pancreatic Arterial and Venous Supply

• Arterial: Blood supply from branches of splenic artery (tortuous), gastroduodenal artery, and superior mesenteric artery.
• Venous: Drainage occurs through corresponding pancreatic veins; ultimately connecting to portal vein for nutrients and to circulatory system overall.

Pancreatic Lymphatics and Nervous innervation

• Lymphatic: Pancreatic lymphatic vessels connect to the superior mesenteric and celiac lymph nodes.
• Nervous: Nerves originate from the vagus and abdominopelvic splanchnic nerves through the celiac and superior mesenteric plexuses.

Liver

• Location: Primarily situated in the right upper quadrant of the abdomen, protected by the ribs.
• Size: Roughly 1.5 kg / 1500g.
• Function: The largest gland processing nutrients, storing glycogen, producing bile, and vital in various metabolic activities.
• Blood supply: 75-80% through hepatic portal vein bringing nutrients, 20-25% arterial blood for oxygen and other crucial elements
• Biliary system: Essential for fat emulsification.

The Kidney, Ureters, and Suprarenal Glands

• Location: Retroperitoneal, situated on the posterior abdominal wall, one on each side of the vertebral column.
• Kidney Function: Removing excess water, salts, and waste from the blood, returning nutrients to the blood
• Attachment: Weak fascial septum separates Suprarenal Glands from Kidneys. Suprarenal glands are attached to the crura of the diaphragm, thus their major attachment.

Biliary Ducts and Gallbladder

• Mechanism: Bile produced by the liver is continually produced, stored, and concentrated in the gallbladder.
• Function: To concentrate & store bile produced by the liver between meals. Also aids in fat emulsification.
• Structure: Composed of a body, neck, and fundus.
• Location: Lies on the visceral surface of the liver, in a specific pit/fossa, with body anterior to superior aspect of duodenum.
• Biliary Duct Pathway: Left/right hepatic ducts create common hepatic duct, which then joins the cystic duct forming the common bile duct.

Liver and Gallbladder Relationship and Location

• Location: The liver mainly occupies the right upper quadrant with the gallbladder nestled within a fossa in its inferior surface.

Test your knowledge on the anatomical structures of the abdomen, including the pancreas, spleen, and liver. This quiz covers their positions, lengths, shapes, and anatomical relationships. Perfect for students studying human anatomy or preparing for medical exams.