A&P Ch. 22 part 13
pancreatic amylase
(almost identical to salivary amylase)- further digests carbs only briefly started in the mouth into oligosaccharides and dissacharides.
microscopy anatomy of the liver/gallbladder
a. *Liver lobules* b. *hepatocytes* c. *portal triad* d. *Kupffer cells* e. *central vein* f. *bile canaliculi*
gross anatomay of the liver
a. consists of a *right lobe* and *left lobe* separated by the *falciform ligament* b. the *caudate lobe* (next to the inferior vena cava) and the *quadrate lobe* (next to the gallbladder) are visible on the inferior surface. c. Bile exits from the right and left lobes of the liver via the *right and left hepatic ducts*. The right and left hepatic ducts merge to form the *common hepatic duct*. The common hepatic duct merges with the *cystic duct* from the gallbladder to form the *common bile duct*. The common bile duct drains into the duodenum via the *Sphincter of Oddi* (aka: *hepatopancreatic shpincter*).
liver's digestive function
a. filters and processes nutrient-rich blood of carbohydrates, proteins, and lipids from the intestine. b. Cholesterol metabolism and regulation of blood cholesterol levels. c. removes drugs and hormones from circulation. d. produces *bile* which emulsifies fats in the small intestine.
composition of pancreatic juice produced by *acini*
a. sodium bicarbonate b. pancreatic proteases c. pancreatic amylase d. pancreatic lipases e. pancreatic nucleases
pancreatic lipases
breaks down lipids into fatty acids and glycerol.
pancreatic nucleases
breaks down nucleic acids such as DNA and RNA.
portal triad
contain 3 vessels at the corners of the liver lobules: 1. *hepatic portal vein* 2. *hepatic artery* 3. *bile duct*. The hepatic portal vein and hepatic artery bring nutrient-rich blood into the liver where it filters through the hepatocytes lining the *liver sinusoidal capillaries* that drain towards the central vein in the middle of each lobule.
central vein
filtered blood enters this vein which then drains into the *hepatic vein* that exits the liver and empties into the inferior vena cava.
liver lobules
form the structural and functional units of the liver.
bile canaliculi
meanwhile, bile produced by the hepatocytes travels opposite through this portal toward the portal triad draining into the *bile ducts* which merge to form either the *right or left hepatic ducts*; exit the liver and moves the bile to the gallbladder for storage.
Islets of Langerhans
release *insulin and glucagon* that are important in carbohydrate metabolism. *These are endocrine cells!*
Kupffer cells
remove debris (bacteria and dead blood cells)
pancreatic proteases
secreted as inactive enzymes but become activated in the small intestine to form the activated: *carboxypeptidase, chymotrypsin* and *trypsin*. These enzymes break down large polypeptides into oligopeptides, tripeptides, dipeptides and some amino acids.
pancreas
secretes pancreatic juice containing buffers and enzymes formed by the exocrine cells called *acinar cells* (or acini). The pancreatic juice drains via the pancreatic duct towards the small intestine. Empties into the duodenum through the sphincter of Oddi along with bile from the liver and gallbladder.
sodium bicarbonate
serves as a buffer of the HCl produced in the stomach
gallbladder
stores and concentrates bile until needed by the small intestine. 1. the gallbladder is divided into 3 regions: *fundus, body* and *neck*. 2. The release of *CCK* by the duodenum triggers dilation of the sphincter of Oddi and contraction of the gallbladder. 3. Bile leaves the gallbladder via the *cystic duct*, combines with the *common hepatic duct* from the liver to form the *common bile duct*. the common bile duct drains into the duodenum via the *sphincter of Oddi*, or aka: hepatopancreatic sphincter.
liver and gallbladder
the liver is the largest internal organ in the body and is responsible for the production of *bile*, an important emulsifier.
hepatocytes
these are liver cells and are in each lobule of the liver. They produce bile and process nutrients