Digestive system comparative anatomy of the liver and pancreas Flashcards
what are the functions of the liver?
waste products
secretion
storage
synthesis
protein, carb and lipid metabolism
immune function
where is the largest gland in the abdominal cavity located?
caudal to the diaphragm
what is the largest gland in the abdominal cavity?
liver
name some species that do not have a gall bladder in the fossa?
horses, rats
where is the gall bladder found?
between the right medial and quadrate lobe of the liver
where does the bulk of the liver lie in all species (and in ruminants?)
bulk of it lies to the right in all species and in ruminants - entirely moved to the right
what is the surface of the liver that is next to the diaphragm called?
parietal surface or diaphragmatic surface
describe the shape of the surface of the liver that is next to the diaphragm:
it is strongly convex surface towards the diaphragm
the liver is concave towards viscera - hence this surface is called the visceral surface, what does viscera mean?
lies against and impressed by stomach, duodenum etc.
what is the visceral surface of the liver marked by?
it is marked by the porta of the liver
what is the porta of the liver?
the visceral surface is marked by the porta of the liver
what happens at the porta of the liver?
the bile duct, portal vein and hepatic vessels enter and leave here
porta is latin for? think of its function/location:
gate
what is the porta of the liver also known as?
as the hilar region of the liver
where is the liver located?
cranial part of the abdomen
what is cranial to the liver?
the diaphragm
what is caudal to the liver?
the stomach, intestinal mass and right kidney
does the right kidney make contact with the liver?
yes
what effect do the adjacent organs have on the liver?
the liver adopts the form of adjacent organs e.g. renal impression of the caudate lobe
describe the location of the liver compared to the stomach in a dog?
to the left of the stomach (spleen)
describe the location of the liver compared to the pancreas, kidney and duodenum in a dog?
it is located on the right of these organs
describe the location of the liver compared to the greater omentum in a dog?
it is located ventrally to the greater omentum
in a dog, what region does the liver reach on the ventral abdominal wall?
it reaches the umbilical region on the ventral abdominal wall
in a dog, what does the most caudal part of the liver cover?
it covers the cranial extremity of the right kidney and reaches the 13th thoracic vertebra
in a dog, where does the liver extend beyond?
it extends beyond the coastal arch ventrally
MORE SO IN PUPS and IN CONGESTIVE HEART FAILURE
Where do we carry out the liver biopsy on a dog?
puncture cadual to the xiphoid process
where does the liver lie within a horse?
completely within the ribcage
describe the location of the horse’s liver compared to the diaphragm?
located obliquely across the diaphragm with the left lobe ventral and right lobe dorsal
where does the caudal margin of the liver of a horse reach?
it reaches the 15th ICS
where do we carry out the liver biopsy-12th ICS on a horse?
on a line between the tuber coxae and point of the shoulder (right hand side)
where do we carry out the liver biopsy-8th ICS on a horse?
at the level of deltoid tuberosity of the humerus
describe the liver of a rabbit:
the liver has five lobes with a deep cleft dividing it into right and left lobes
how many lobes does the liver of a rabbit have?
5
what kind of biopsy of the liver can be taken of a rabbit and where do we take this biopsy?
an ultrasound-guided biopsy can be taken ventrally from any lobe
which lobe of a rabbit’s liver has a narrow attachment?
the caudate lobe
describe the narrow attachment on the caudate lobe of a rabbit?
there is a narrow attachment to the porta region of the liver and this could be a site of liver torsion
is there a gall bladder present in a rabbit?
yes
where does the liver reach to (cover) in a cow?
liver reaches dorsally as far as the last rib
where is the liver biopsy site on a cow?
it is 10th ICS: 1/4 the way down the length of the rib
where does the gall bladder rest in a cow?
rests 10th ICS
what is the liver covered by?
by serosa which is overlying thin connective tissue capsule (tunica fibrosa)
liver: what is serosa?
visceral peritoneum
liver: in what animal is tunica fibrosa especially strong in?
pigs
what liver attachment has no supportive function? what other kind of function does it have?
peritoneal folds (no supportive function) BUT carry blood vessels, nerves and lymphatics
liver: where is the falciform ligament found?
between the liver and diaphragm and the ventral abdominal wall
liver: what is the round ligament and where is it found?
it is a fibrous strand in the free edge of the falciform ligament
liver: which ligament is the umbilical vein remnant?
falciform ligament
what is the lesser omentum?
it is an attachment of the liver
what ligaments are found in the lesser omentum of the liver?
hepatoduodenal and hepatogastric ligament
what function do ligaments have?
they have a supportive function - attach to the liver firmly
what do the peritoneal folds serve as?
serve to fix organs in position - serve as ligaments
where is the coronary ligament of the liver found and what does it attach to?
they surround the caudal vena cava and attaches the liver to the central tendon of the diaphragm
where is the triangular ligament of the liver found?
it extends between the dorsal part of the liver on each side of the diaphragm
where do the right and left triangular and coronary ligaments pass to of the liver?
they pass to the diaphragm from the parietal surface
describe the cores of the right and left triangular and coronary ligaments of the liver?
they have fibrous cores
describe the blood supply of the liver?
it has a dual blood supply
what does the dual blood supply of the liver consist of?
the hepatic portal vein and the hepatic artery
what is the hepatic portal vein of the liver?
it is a large vein carrying nutrient rich blood from the unpaired organs into the liver
what percentage of the blood flow to the liver comes from the hepatic portal vein?
60-70% blood flow
what does the hepatic artery of the liver do?
supplies fresh oxygenated (nutritional) blood
what blood does the hepatic portal vein receive?
receives the venous blood from all unpaired abdominal organs
give examples of the unpaired abdominal organs?
stomach, pancreas, spleen and intestines
what happens to the blood from the portal vein and hepatic artery branches?
it mixes within the hepatic sinusoids before collecting in central veins
what happens to the central veins?
they merge and eventually form hepatic veins that drain into the abdominal portion of the caudal vena cava
what nerves innervate the liver?
both the sympathetic and the parasympathetic nerves
where does the liver receive fibres from?
from the vagal trunk
where does the liver receive sympathetic axons from?
from the celiac plexus/ganglion
how do the vagal axons reach the abdomen?
by passing through the diaphragm with the oesophagus
what is the basic structure of the liver?
it is the hepatic lobule-hexagon shaped
what is formed at each corner of the liver and what makes up this structure?
the bile duct - at each corner an arteriole (from hepatic a.) a venule (from portal v.) and a samll bile duct from the bile duct
what is the arteriole, the venule and the small bile duct commonly referred to as?
the portal triad
what does each portal triad provide?
they may provide blood to the several adjacent hepatic lobules
what are the three major structures that the portal triad (or portal tract) contains?
portal vein (PV) hepaptic artery (HA) and bile duct (BD)
where do the arteriole and venule of the hepatic lobule empty their blood?
they empty it into the spongy liver lobule
what runs between the portal triad and central vein in the hepatic lobule?
blood capillary beds
what are capillary beds lined with?
lined by fenestrated, leaky endothelium known as liver sinusoids
meaning of fenestrated?
having one or more openings or pores.
how is the blood flowing into the hepatic lobule of the liver drained out?
via the central vein
what is bile produced by?
by the sheets of hepatocytes
what is bile discharged into?
into bile canaliculi
what do the bile canaliculi unite to form?
they form the interlobular ducts - lobular ducts
what are the names of the ducts within the digestive system?
the hepatic ducts, cystic ducts and the bile duct
where is the pancreas found?
the dorsal part of the abdominal cavity and it often presses against the stomach and liver
what is the pancreas?
a small lobulated gland with two lobes joined by the body which is in contact with the pylorus
where is the right lobe of the pancreas found?
it is within the mesoduodenum next to the duodenum
where is the left lobe of the pancreas found?
it lies in the deep leaf of the greater omentum
what supplies blood to the pancreas?
the coeliac and cranial mesentric artery branches
where does the pancreatic duct open into?
opens into the duodenum together or just beside the bile duct
which is the greater and which is the lesser pancreatic duct?
GREATER = pancreatic duct that open beside the bile duct into duodenum
LESSER = accessory pancreatic duct which opens on the opposite side
where does the accessory duct open into?
open on the opposite side to the greater pancreatic duct
In which species does only one duct commonly survive?
some e.g. sheep, pig
when do pancreatic and bile ducts open in a horse?
they open at the first bend of the duodenal sigmoid flexure
where does the common bile duct enter the duodenum in a dog?
it enters the duodenum at the major duodenal papilla adjacent to the pancreatic duct
when do the bile duct and pancreatic duct conjoin in a cat?
just before they enter into the major duodenal papilla
ligaments and peritoneal folds are?
connecting peritoneum
What is the liver intimately attached to?
the diaphragm
what side of the body does the liver occupy in most species?
right side of the body
which lobe of the liver makes an m=impression on the right kindey as renal fossa?
caudate lobe
where would you do the liver biopsy on a horse on the left hand side?
Liver biopsy-8th ICS: at the level of deltoid tuberosityof the humerus
where does the ruminants liver extend from?
extends from 6th ICS to the 13th ICS
ICS?
intercostal space
which peritoneal fold is removed when performing cranial ventral abdominal incision to improve visualisation?
falciform
which ligament divides the liver into right and left halves?
falciform
which ligament is short and attaches liver to the central tendon of the diaphragm?
coronary ligament
which vessel delivers livers oxygenated blod supply?
hepatic artery
hepatic artery?
artery –> coeliac (it is a branch of this)
which organ contains the sinuoids?
liver
in the dog, where does the right love of the pancreas lie?
next to the descending duodenum
what is the peritoneal fold that attache sintestine to the dorsal abdominal wall is?
messentery
does a horse have a gall bladder?
no
list four major functions of the liver:
Secreting bile for use in digestion
Filtering and neutralising foreign materials
Storing iron, glycogen, Vit A,D, B12
Carbohydrate, fat and protein metabolism
what is the function of sacculations (haustra) in the caecum and colon of the pig and horse?
Sacculations also called haustra seem to act like bucket! by accomodating extra volume, they can help to prolong the retention of contents, hence allowing more time for microbial digestion.
