M11S1: Accessory Digestive Organs Flashcards
The accessory digestive organs review
-significant part of acquiring nutrients from food
-provide enzymes for breakdown of food molecules and bile for digestion of dietary fat
-important process in storage of molecules that provide energy for body
Include:
Liver
-produces bile for digestion of fats
-stores dietary glucose in form of glycogen so later broken down
-used for production of energy
-metabolism of toxins, drugs and alcohol in blood
Gallbladder
-small organ underneath liver
-storage and release of bile in digestive system
Pancreas
-mixed gland (endocrine and exocrine functions)
-endocrine =controls blood glucose
-exocrine = secrete digestive enzymes into intestine
The liver: location and lobes
-sits in upper right abdominal quadrant, inferior to diaphragm and anterior to inferior vena cave (IVC)
Liver has 4 lobes:
1. Right
2. Left
3. Caudate
4. Quadrate
*refer to goodnotes
Ligaments of liver
-attach the liver to the surrounding abdominal peritoneum (thin membrane that lines the abdominal cavity and covers most of the abdominal organs) and diaphragm
-right and left lobes separated by falciform ligament
-coronary ligament suspends the liver from the inferior surface of diaphragm
*refer to goodnotes
Porta hepatis (Hilum)
-where hepatic vessels and ducts enter and leave the liver
-located on inferior side of liver, surrounded by four lobes
*refer to goodnotes
Structures of porta hepatis (hilum)
-3 structures that enter and leave porta hepatis
Common hepatic duct
-drains bile produced by liver
-joins with cystic duct of gallbladder to form common bile duct
Portal vein
-carries nutrient rich blood from digestive system into liver, where those nutrients absorbed from digested food can be stored
-if any toxins or drugs are ingested, travel through this vessel into liver to be metabolized
Hepatic artery
-carries oxygenated blood to liver and branches to supply each lobe
*refer to goodnotes
Liver histology: hepatocytes
-functional unit of liver is the hexagonal-shaped liver lobule
-each lobule made up of simple cuboidal liver cells known as hepatocytes, arranged in plates (cords) that radiate outward from central vein
-between plates of cells are spaces called sinusoids where venous blood flows
*refer to goodnotes
Portal (hepatic) triads
-branches of hepatic artery, portal vein and common hepatic duct from porta hepatis
-within the liver there are many triads, as each lobule surrounded by six triads, one at each corner of hexagon
*refer to goodnotes
Liver lobule: flow of venous blood
-nutrient rich blood from portal veins travel into sinusoids
-in sinusoids the nutrients from blood taken up into the hepatocytes
-then blood in sinusoids drains into central veins, which join to form the hepatic veins
-finally blood from each hepatic vein drains to inferior vena cava and eventually to the heart
Liver lobule: flow of bile
-bile produced by hepatocytes to aid in digestion of dietary fats
-from hepatocytes, bile drains into small channels, called canaliculi, that empty into bile ductules of portal triad, and eventually into hepatic ducts
-hepatic ducts join to form the common hepatic duct
What are the general functions of the liver
-within digestion is to produce bile, which is used in emulsification (breakdown of fat into smaller fat droplets. Process assisted by action of bile salts) of fats and cholesterol
-also receives all of the nutrient-rich blood from the digestive system and able to store nutrients such as glucose within its cell for later use
*refer to goodnotes
What is cirrhosis
-slow, progressive disease in which healthy liver tissue is replaced by scar tissue
-presence of scar tissue prevents the liver from functioning normally
*refer to goodnotes
Histology of liver cirrhosis and what that causes
-cirrhosis tissue has become fibrotic and interspersed with fatty tissue
-this causes hepatocytes to lose their cord-like arrangement
This causes:
Block flow of blood and bile through portal triads of liver resulting in jaundice (yellow colouration) of skin due to build of bile, and a distended abdomen due to build up of fluid from venous system
Gallbladder
-pear-shaped muscular sac that lies inferior to the right lobe of liver
-function is to store and concentrate bile not immediately required for digestion
*refer to goodnotes
Anatomical features of gallbladder
-3 regions
Fundus:
Region is fond anteriorly
Body:
This region found between the fundus and neck
Neck:
-region found posteriorly
-connected to the cystic duct
*refer to goodnotes
Biliary system
-consists of interconnected ducts that connect liver and gallbladder
-duct system stores and drains bile into duodenum
3 main ducts
Hepatic ducts
-the right and left hepatic ducts from right and left lobes of liver drain bile into common hepatic duct
Cystic duct
-attaches to the common hepatic duct and functions to transport bile to and from the gallbladder
Common bile duct
-common hepatic duct and the cystic duct meet to drain bile into the common bile duct, which enters the duodenum
*refer to goodnotes
