accessory glands Flashcards
what are the accessory glands of the digestive system?
specialised organs that are not part of the GI tract but secrete digestive juices into the GI tract.
what are the accessory glands in the digestive system?
salivary, pancreas, liver
what is the general structure of an accessory gland?
has a main duct which branches into smaller ducts which end at acini.
what is the role of acini?
to secrete digestive juices into the main duct where they will then be carried to the lumen of the GI tract.
what are the types of salivary glands?
parotid: ear level
sublingal: below the tongue
submandibular: below the jaw
what is saliva made up of?
water, solutes and enzymes
where is the pancreas located?
beneath and behind the stomach
what is the structure of the pancreas?
has an exocrine part: pancreatic juice is secreted by the acini into the pancreatic duct. it is then secreted through an opening (ampulla of vater) into the small intestine
has an endocrine part:
islets of Langerhans which secrete insulin and glucagon into blood.
what is pancreatic juice made of?
bicarbonate (neutralise acid), zymogens (inactive enzymes), amylases, lipases, proteases, nucleases.
where are zymogens stored?
in granules in acini
how do zymogens become active?
activated by enteropeptidases on the surface of enterocytes (type of epithelial cell in s intestine)
what is the function of the liver?
bile secretion (produced by hepatocytes)
processes nutrients
removes old blood cells
eliminates waste products
breaks down haemoglobin into bilirubin and iron.
what is bile made of?
bicarbonate, pigments, phospholipids, cholesterol, bile salts, inorganic ions.
what is the structure of the liver?
has two lobes.
has hepatocytes which absorb substances for bile in sinusoids
outline the bilary system
bile produced by hepatocytes
bile secreted into bile canaliculi
into bile duct
into common hepatic duct
through ampulla of vater
through sphicter of Oddi
back to gall bladder for storage.
