Digestive System (Liver and Pancreas) Flashcards
What is the main function of the pancreas
Secrete digestive enzymes that act in the small intestine
Secrete hormones
What is the main function of the liver?
Secrete bile that helps in fat digestion
Metabolize carbohydrate, fat and protein to detoxify toxic substances and drugs
What are the two types of pancreas?
Exocrine and endocrine
Exocrine pancreas
95% of pancreatic mass with acinar and centroaciner cells
Acinar cells
Secrete enzymes first secreted as pro-enzymes then activated in the small intestine
Centroacinar cells
Secrete large quantities of enzyme-poor alkaline fluid that neutralizes acidic chyme
What are the centroacinar cell secretions controlled by?
Enzymatic: cholecystokinin hormone
Alkaline fluid: regulated by secretin hormone
Both hormones produced by enteroendocrine cells
What are the pancreatic ducts?
Intercalated, intralobuar and interlobular that bring the pancreatic secretion into the duodenum
Endocrine pancreas
Islets of Langerhans with:
Alpha cells (20%)- produce glucagon and elevate blood glucose
Beta (70%)- produce insulin to decrease blood glucose level
Delta (5%)- produce somatostain that regulates secretion of alpha and beta cells
Liver
Largest glands of the body
Lobes and lobules
Enclosed by CT
Has portal verin, hepatic artery, hepatic vein, lymph vessels and hepatic ducts
Portal vein
Brings blood from the gut
70% of the functional blood supply
All materials absorbed via the intestine reach liver via PV except chylomicrons
Hepatic artery
Brings arterial blood from the aorta
20-30% nutritional
Hepatic vein, Lymph vessels and hepatic duct
Vein: takes blood away to the heart
Vessels: drain lymph
Duct: transport bile to the duct
Liver lobule
Easily recognized in pig and camel
Hexagonal mass with central vein, plates of hepatocytes (peripheral), sinusoids, and portal triad
Sinusoids blood supply
Receive blood from portal vein and hepatic artery and drain into central vein
What are the 2 main structural and functional parts of the liver lobule?
Sinusoids and hepatic plates
Sinusoid characteristics
Wide lumen
Fenestrated endothelial cells
Discontinuous BL
Space of Disse (surrounding space)
Kupffer cells
Kupffer cells
O: monocytes
F: remove foreign particles and old RBCs (phagocytize)
Hepatocytes
Polyhedral cells with 1 or 2 nuclei
Well-developed RER, SER and Golgi, lysosomes, peroxisomes
Bile canaliculi
Bile canaliculi
Small tunnel like extensions of intercellular spaces
Receive bile from hepatocytes and carry it o canals of Herring
Hepatic functions
Exocrine: production and release of bile
Endocrine: plasma protein
Metabolic: storing glycogen and lipids
Gluconeogenesis
Detoxification
Classification of liver lobules
Classical and portal lobules
Classical lobule
Hexagonal
Central vein
Portal triads at each corner
Portal lobule
Triangular in cross section
Central vein @ each corner of triangle
Portal triad in the center
Hepatic acinus of Rappaport
Diamond shaped regions
Central vein at two ends of the diamond
Portal triad in center
Liver regeneration
Cell renewal slow in a healthy liver
If three fourths surgically removed it can regenerate to its original in a short period of time
Gall bladder
Sac-like structure
Lined by simple columnar with microvilli
F: store and concentrate bile bu absorbing fluid and some electrolytes
Which animal doesn’t have a gall bladder?
Horses
