Pancreas and Liver Flashcards
What does endocrine mean?
- release hormones
- directly into bloodstream or tissues
What does exocrine mean?
- release chemical substances to outside of body or to another surface within body
- released through ducts
What are the exocrine functions of the pancreas?
- neutralise acid (because of acid added from stomach)
- deliver enzymes for macronutrient digestion in duodenum
What are the main secretory cells of the pancreas?
acinar cells
- clusters of these cells are connected by intercalating ducts
- these intercalating ducts form together to make the main pancreatic duct
- lining cells add ions nd secretions
Where does the pancreas lie?
- in C-shaped curve of duodenum - head, neck, body, tail, uncinate process
- retroperitoneal (except tail)
- close to major blood vessels so hard to access
Where dose the pancreas get its blood supply from?
- via the splenic artery (from coeliac trunk)
- pancreatico-duodenal arteries ( from SMA or celiac trunk)
What does the exocrine pancreas deliver?
- enzymes
- ions
- serous solutions
What aids the neutralisation of stomach acid?
HCO3- (to neutralise CL- conc)
How are enzymes released into the intestines?
secreted in their inactive form to be activated in the small intestine
What does the main pancreatic duct combine with?
- the common bile duct
- 3 components of the sphincter of Oddi
What do acinar cells secrete?
- enzymes
- ions
- HCO3-
What do ductal cells secrete?
- serous
- HC03-
What does exocrine pancreas regulation depend on?
phase of digestion
- cephalic - vagus nerve stimulates secretions by releasing Such and VIP
- Gastric - mediated by vasovagal reflexes
- intestinal - controlled hormonally by secretions
What are the functions of the liver?
- synthesis and secretion of bile
- storage of glucose, glycogen, proteins, vitamins, fats - glycogen depending of fed/fasted
- detoxification of metabolic waste - ammonia, ethanol, drug
- synthesis of blood clotting and anticoagulant factors (fibrin and prothrombin)
- immune system function - removal of intestinal bacteria from portal blood so none is in systemic circulation -produces large amounts of lymph
What is the structure of the liver like?
- left and right lobes
- quadrate lobe next to gallbladder
- caudate lobe next to IVC
- diaphragmatic surface is “bare” - no peritoneal covering
What does bile consist of?
- bile pigments/acids - bilirubin mainly
- cholesterol
- phospholipids
- fatty acids
- water
- electrolytes
What is the main exocrine function of the liver?
- produces and secretes bile - “hepatobilary system”
What is the function of bile acids?
- emulsify lipids
What is the function of water and electrolytes in bile?
NA+ and CL- are reabsorbed - causing isometric water reabsorption to concentrate bile
How does bile secretion occur?
- hepatocytes secrete bile into canaliculi - across bile ducts until they form the common hepatic duct
- bile flow is in opposite direction of blood from hepatic artery and portal vein
Where does bile enter the intestines?
from common bile duct into the
- duodenum or
- gallbladder
What controls the flow of bile?
sphincter of odd
- when contracted - bile goes mainly to gallbladder
- when relaxed - bile goes mainly to duodenum
Where is the liver found?
lies across the upper abdomen
under diaphragm
surrounded by peritoneum (except bare area)
may be palpable below the costal margin
What surrounds the liver?
Glissons capsule - thin connective tissue layer with extensions into the organ between the lobes
What supplies the liver with blood?
- hepatic portal vein - brings absorbed nutrients from stomach and gut
- hepatic artery - supplies hepatocytes with oxygen
What drains bile?
canaliculi into bile ductules and eventually into bile ducts
What are liver cells known as?
hepatocytes
What is venous drainage of the liver done by?
- hepatic veins that enter the inferior pen cava
What is the function of the gallbladder?
- stores and distributes bile - in concentrated form
How does the gallbladder work?
- contracts to expel bile in response to CCK (same os sphincter of Oddi to relax)
- vagal stimulation causes weak contraction
- somatostatin and noradrenalin inhibit bile acid secretion
