Accessory Digestive Organs Flashcards
Liver Functions (3)
- Metabolic- hepatocytes regulate circulating levels of nutrients; remove metabolic wastes and toxins
- Hematological- processes and purifies blood from newly absorbed nutrients from small intestine
- Digestive- produces and secretes bile
*largest visceral organ and has mass of ~1.5kg
Accessory Digestive Organs (4) and Functions
-Liver, gallbladder, pancreas, salivary glands
-Produce, store, and secrete digestive enzymes and buffers
-Both the liver and pancreas have functions in other body systems
Liver Location
-Immediately inferior to diaphragm, in right upper abdomen
-Sits superior and lateral to the stomach, right kidney and intestines
Surfaces of Liver (2)
- Diaphragmatic surface:
-Superior and anterior surfaces, smooth and follows curve of diaphragm and body wall
*Bare area: area of liver in direct contact with the diaphragm, no visceral peritoneum - Visceral surface:
-Posterior and inferior surfaces, has impressions from the stomach, small intestine, right kidney and large intestine
Lobes of the Liver (4)
- Right lobe
- Left lobe
- Caudate lobe
- Quadrate lobe
*gallbladder sits inferiorly, IVC sits superiorly
Ligaments of the Liver (4)
- Falciform ligament- attaches liver to anterior body well, divides into right and left lobes
- Coronary ligament- suspends liver from diaphragm
- Right and left triangular ligaments- on superior aspect towards lateral body wall (top corners)
- Round ligament/ligamentum teres- thickening of inferior margin of falciform ligament, embryological remnant of umbilical vein
Gallbladder Function
-Stores and concentrates bile produced by the liver
(Bile helps in digestion of dietary lipids through emulsification)
Gallbladder Location
-Hollow, pear-shaped, muscular sac on right visceral surface of the liver
-Lateral to the stomach
-Closely related to the duodenum
Ducts Connecting Gallbladder and Liver
-Right and left hepatic duct
-Common hepatic duct
-Cystic duct
-Common bile duct
*common hepatic duct joints cystic duct to form common bile duct, which empties into the duodenum
Gallbladder Blood Supply
Arterial supply: cystic artery (branch of hepatic artery proper)
Venous drainage: cystic vein into hepatic portal vein (mirror arterial supply)
Clinical Case: Gallstones
-Form when bile stored in gallbladder hardens into stone-like material
-Too much cholesterol, bile salts, or bilirubin (bile pigment) can cause gallstones
-Treatment is surgery
Porta Hepatis Components (3)
A.k.a hilum of liver, region that contains:
- Portal vein
- Hepatic artery proper
- Common hepatic duct
Origin of Artery in Porta Hepatis
Abdominal aorta -> celiac trunk -> common hepatic artery -> hepatic artery proper
Origin of Vein in Porta Hepatis
-Union of the superior mesenteric vein and splenic vein (posterior to pancreas) forms the hepatic portal vein
-Portal vein carries venous blood from the small and large intestines, stomach, pancreas, gallbladder, spleen
Hepatic Portal System
Portal system= connection between 2 capillary beds
-Nutrient-rich venous blood drains from veins of the stomach and intestines and travels to the liver for processing
Processing at the Liver
-Lobules are the functional unit of the liver
-They are hexagonal
-At the centre of each lobule there is a central vein, and at each corner there’s a portal area containing a portal triad
-As blood flows towards the centre, hepatocytes absorb and secrete substances, altering the blood entering systemic circulation.
-Blood provided by the hepatic artery proper and the hepatic portal vein flows from portal area towards the central vein, which coalesce into hepatic veins
Portal Triad
-Small branch of the hepatic portal vein
-Small branch of the hepatic artery proper
-A bile duct
Scenario: Alcohol Consumption
- The alcohol passes from the oral cavity to the esophagus and into the stomach
- The stomach and small intestine absorb the alcohol
- The hepatic portal vein carries the blood to the liver
- Enzymes metabolize alcohol in the liver
- Hepatic veins carry the blood to the IVC to go back into systemic circulation
Bile Flow to Portal Areas
Right and left hepatic ducts form common hepatic duct
-Hepatocytes produce bile which flows outward to portal areas
-Small projections called bile canaliculi carry bile to the bile duct of the closest portal area
Summary of Porta Hepatis
-Hepatic artery proper delivers oxygenated blood to the liver
-Hepatic portal vein delivers deoxygenated, but nutrient-rich blood from the digestive tract
-Common hepatic duct carries bile produced by the liver away
Pancreas: Exocrine and Endocrine Functions
Exocrine:
-Produces digestive enzymes and alkaline buffers to neutralize acidic chyme
-Duct system within pancreas carries the fluid to the duodenum
Endocrine:
-Produces hormones like insulin
-Secreted into interstitial fluid and then into bloodstream
Appearance and Location of the Pancreas
~15cm long
-Pinkish/grey in colour
-Located posterior to stomach
-Head of the pancreas is nestled in the curve of the duodenum
-Extends left towards the spleen
*area of abdominal romance= head of pancreas is enfolded in arms of duodenum
Parts of the Pancreas (5)
-Tail
-Body
-Neck
-Head
-Uncinate process
Blood Supply to the Pancreas
Arterial supply: branches of the splenic artery and the pancreaticduodenal artery
Venous drainage: splenic vein
Gallbladder and Pancreas Emptying
-Secretions from the gallbladder and pancreas are transported to the duodenum via duct systems
-The fluids enter the duodenum through papillae
-A papilla is a small, rounded protuberance on an organ or part of the body
