Section 1 Flashcards
What does the liver do?
- produces bile for the digestion of fats
- stores dietary glucose in the form of glycogen, so that it can later be broken down and used for the production of energy
- plays a role in the metabolism of toxins, drugs, and alcohol in the blood
What is the gallbladder?
- small organ underneath the liver
- for storage and release of bile
What is the pancreas?
- a mixed gland (both endocrine and exocrine functions)
- endocrine: controls levels of blood glucose
- exocrine: secretes digestive enzymes into the intestine
Is the pancreas an endocrine or exocrine gland?
Both
What are the lobes of the liver?
Right, left, caudate, quadrate
What are the ligaments of the liver?
They attach the liver to the surrounding abdominal peritoneum and the diaphragm
What is peritoneum?
A thin membrane that lines the abdominal cavity and covers most of the abdominal organs
What are the right and left lobes of the liver separated by?
The falciform ligament
What suspends the liver from the inferior surface of the diaphragm?
The coronary ligament
What is the porta hepatis?
- the hilum of the liver
- aka hepatic portal
- this is where the hepatic ducts enter and leave the liver
- located on inferior side of the liver, surrounded by the four lobes
What are the three structures that enter and leave the porta hepatis?
Common hepatic duct, portal vein, and hepatic artery
What is the common hepatic duct (what does it do/join)?
- drains bile produced in the liver
- joins with the cystic duct of the gallbladder to form the common bile duct
What is the portal vein/what does it do?
- carries nutrient rich blood from the digestive system into the liver, where those nutrients absorbed from the digested food can be stored
- carries any ingested toxins or drugs into the liver to be metabolized
What does the hepatic artery do?
Carries oxygenated blood to the liver and branches to supply each lobe
What is a liver lobule?
- the functional unit of the liver
- hexagonal-shaped
- each one is made up of simple cuboidal liver cells called hepatocytes arranged in plates that radiate outward from a central vein
- between the plates of cells are spaces called sinusoids where venous blood flows
What are portal (hepatic) triads?
- branches of the hepatic artery, portal vein, and common hepatic duct from the porta hepatis
- there are many triads in the liver as each lobule is surrounded by six triads, one at the each corner of the hexagon
Describe the flow of venous blood in the liver lobule.
Nutrient rich blood from the portal veins travels into the sinusoids. In the sinusoids, the nutrients from the blood are taken up into the hepatocytes.
Then, the blood in the sinusoids drains into the central veins, which join to form the hepatic veins. Finally, blood from each hepatic vein drains into the inferior vena cava and eventually to the heart.
With regards to digestion, what are the general functions of the liver?
- produce bile (used in emulsification (breakdown) of fats and cholesterol)
- receive nutrient rich blood and stores the nutrients within its cells as glucose for later use
What is liver cirrhosis?
A slow, progressive disease in which healthy liver tissue is replaced by scar tissue. The presence of scar tissue prevents the liver from functioning normally
Cirrhotic tissue becomes fibrotic and interspersed with fatty tissue. This causes hepatocytes to lose their chord-like arrangement. What would you speculate the symptoms of cirrhosis in the liver be?
- block the flow of blood and bile through the portal triads of the liver resulting in jaundice (yellow colouration) of the skin due to buildup of bile
- a distended abdomen due to a buildup of fluid from the venous system
What is the gallbladder?
- a pear-shaped muscular sac
- lies inferior to the right lobe of the liver
- stores and concentrates bile that is not immediately needed for digestion
What are the three regions of the gallbladder?
- fundus - anterior
- body - between fundus and neck
- neck - posterior, connected to cystic duct
What are the interconnected ducts that connect the liver and the gallbladder? And what does this duct system do?
- hepatic ducts
- cystic duct
- common bile duct
This duct system stores and drains bile into the duodenum
What do hepatic ducts do?
The right and left hepatic duct from the right and left lobes of the liver drain bile into the COMMON HEPATIC DUCT
What does the cystic duct do?
- attaches to the common hepatic duct
- functions to transport bile to and from the gallbladder
What does the common bile duct do?
the common hepatic duct and cystic duct meet to drain bile into the common bile duct, which enters the duodenum
What is the pancreas?
- a lobular organ
- lies deep to the stomach
- mixed gland (both endocrine and exocrine functions)
- exocrine portion secretes enzymes that aid in digestion of food
What are the three divisions of the pancreas?
Head, body and tail
What is the position of the head of the pancreas?
Sits in the concavity of the duodenum on the right side of the abdominal cavity
What is the position of the body of the pancreas?
Extends towards the left, passing behind the stomach and tapering to become the tail
Position of tail of the pancreas?
Abuts the medial side of the spleen
What is the main pancreatic duct?
- collects the exocrine products of the pancreas
- fuses with the common bile duct to empty into the duodenum at the hepatopancreatic ampulla of Vater
Describe the histology of the pancreas.
- a mixed gland
- 99% exocrine, 1% endocrine
- islets of Langerhans scattered within the exocrine portion
Describe the exocrine function of the pancreas?
- involves the secretion of pancreatic juices from the pancreatic acini into the duodenum
- pancreatic juices are rich in digestive enzymes and contain bicarbonate ions to neutralize acid from the stomach
