accessory digestive glands Flashcards
what are salivary glands
exocrine glands (glands with ducts) that secrete substances that are transported to somewhere else
what is the liver
large lobbed organ involved in many metabolic processes
completely peritonised
what is the gallbladder
- small organ beneath the liver
- stores bile - breaks down fat
- attached to inferior surface of liver via cystic duct
what is the pancreas
- retroperitoneal gland
- lies behind the stomach: transversely and posterior to greater curvature of stomach
- blood sugar regulation
- divisions: head, body, tail
major salivary glands
- parotid glands
- submandibular
- sublingual
minor salivary glands
- lingual glands (tongue)
- palatine glands (palate)
- buccal (cheeks)
- labial (lips)
which gland secrete most of the saliva
submandibular
what is the parotid gland
largest of the 3 pairs
irregular in shape
has one duct
formed mainly of serous cells
position of parotid glands
anterior to ear
extends to lower border of mandible and up to zygomatic arch
what does the parotid gland cover/cross
posteriorly it covers the anterior part of sternocleiodmastoid muscle
anteriorly portion halfway across masseter muscle
duct crosses masseter and pierces buccinator
where does the parotid gland duct enter the oral cavity
in cheek near upper second molar
what is the submandibular gland
half size of parotid
secretes most of the saliva
has one duct
formed of mixture of serous and mucous cells
position of submandibular gland
lump along inferior border of posterior part of mandible
how does submandibular enter the oral cavity
duct exits gland and passes to mucous membrane on floor of oral cavity
opens in oral cavity at the side of the lingual frenulum of tongue
sublingual gland
smallest of the three
almond-shaped
doesn’t have awell-defined duct - there is several ducts (around 10-12)
formed of mainly mucous cells
position of sublingual gland
under the tongue below mucous membrane in floor of oral cavity
how does sublingual enter the oral cavity
gland opens into floor of oral cavity through the small ducts (all enter roughly the same area)
types of saliva
viscous and watery
all glands are a compound of
acing/alveoli glands
types of cell type of acinar glands
- serous cells that produce watery saliva
- mucous cells that produce viscous saliva
ligaments of anterior surface of liver
falciform ligament
round ligament
lobes in the liver
left (small)
right (largest)
caudate
quadrate
division between lobes in the liver
- inferior vena cava (IVC): right and caudate lobes
- quadrate lobe: left lobe and gallbladder
how is the liver supplied with oxygenated blood
hepatic artery and portal vein
function of common hepatic duct
exit of bile out of liver
what are the liver lobules
divisions in lobes
hexagonal with plates of hepatocytes
plates radiate outward from central vein
what is a portal triad
at each of the 6 corners of lobule
- branch of hepatic artery
- branch of portal vein
- branch of hepatic bile duct
where are the liver sinusoids
between plates
where are the kupffer cells
in the sinusoid walls
where is mixed blood emptied
into central vein which merge to form hepatic veins which join the IVC
what is the bile
- produced in liver and collected in canaliculi
- transported to bile duct that branches at triad
- flows in right and left hepatic ducts (common hepatic duct) which leaves the liver at the porta hepatis and heads toward the duodenum
blood supply to liver
two ways:
25% from hepatic artery (directly from the heart)
72% from portal vein (it receives secondary blood, blood that has already been through over organs)
- these two loops are in constant interaction and alteration of flow to one will inversely affect the other
- by the time the blood gets to the liver, the blood pressure is very low
- liver is vulnerable to drops in blood pressure
how is the GI tract blood-supplied
- coeliac trunk supplies foregut
- superior mesenteric supplies midgut
- inferior mesenteric supplies hindgut
hepatic artery
arises directly from coeliac trunk
gives off two branches
then continues as hepatic artery proper - supplies liver with direct oxygenated blood supply (30%)
metabolic functions of liver
carbohydrates: glycogen to glucose and vice versa amino acids and lactic acid to glucose lipids: stores trigycerides and synthesises lipoproteins proteins: protein metabolism
other functions of liver
detoxification, excretion of billirubin (sweeps dead red blood cells)
storage of glycogen, vitamins and minerals
synthesis of bile salts used for the emulsification and absorption of fats and cholesterol
phagocytosis - kupffer’s cells
muscle layers of gallbladder
- inner mucosa (rugae)
- muscularis (smooth muscle)
- serosa
function of gallbladder
store and concentrate bile
endocrine functions of pancreas
1%
ductless
islets of Langerhans cells secrete hormones (insulin and glucagen) into blood vessels (directly into blood stream)
exocrine functions of pancreas
99%
ducts
acinar cells secrete digestive enzymes into pancreatic duct
these cells are similar to the saliva cells
which two ducts are formed by the uniting of smaller ducts where pancreatic secretion go into
- main pancreatic: joins common bile duct (at hepatopancreatic ampulla)
- accessory: empties directly into duodenum
- they both enter duodenum at major duodenal papilla
what forms the common hepatic duct
right and left hepatic ducts unite to form it
how is the common bile duct formed
joining of common hepatic duct and cystic duct (gallbladder)
what is the duodenal papilla
where common bile duct and main pancreatic enter the descending duodenum
