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list 7 general functions of the liver and examples

1) metabolic conversions
2) secretory - bile
3) excretory - urea and uric acid
4) synthetic - globulin, albumin, prothrombin, clotting and anti-clotting factors
5) storage - lipid, glycogen (glucose)
6) detoxifies
7) filters blood - removes foreign particulate matter


position of liver in terms of other organs, what plane sits in, what side sits and how held in position

positioned between the diaphragm cranially and the stomach and intestinal mass caudally
- It extends across the median plane
○ bulk lies to the right in all species
-held in position largely by the pressure of the viscera and by its close attachment to the diaphragm.


what percentage of body weight is the liver in carnivores, omnivores and herbivores

○ 3-5% of body weight in carnivores
○ 2-3% in omnivores
○ 1-1.5% in herbivores.


palpation for the liver in the dog

right side doesn't go beyond costal arch so not palpable unless diseased
Left side does slightly extend beyond costal arch so could be palpable


what encloses the liver beneath the serosa

the tunica fibrosa


what are the two surfaces of the liver and what do they contact

1) Cranial (parietal) or diaphragmatic surface – convex and fits into the concavity of the diaphragm
2) Caudal or visceral surface - concave and in contact with the visceral organs - has portal area for portal vein etc


what does the porta of the liver contain

- the hepatic artery;
- nerves and lymphatic vessels;
- the portal vein
- and the common bile duct.
- also the Fossa of the gall bladder,
containing the gall bladder, which lies between the quadrate and right medial lobes (dog).


what are the two borders of the liver, where do they go and what is present in one of them

1) Dorsal border - Is extended further caudally and dorsally on the right side by the caudate process which carries a deep impression for the cranial pole of the right kidney.
Towards the median plane, the dorsal border carries a groove for the passage of the caudal vena cava (so goes through middle of liver) and to the left of this a notch for the oesophagus
2) Ventral border - sharp edged and continuous around the periphery of the organ, except dorsally.


List the lobes in the dog

1) left lateral
2) left medial
3) quadrate
4) right medial
5) right lateral
6) caudate process
7) papillary process


List 6 ligaments involved with the liver

1) coronary
2) falciform
3) right and left triangular
4) hepatorenal
5) round
6) lesser omentum


what are the 3 ligaments that tether the liver to the diaphragm and where found

1) coronary ligament - laterally continuous from the triangular ligaments
2) facilform - fat-filled fold in the dog passes from abdominal wall to diaphragm and liver where disapears into the umbilical fissure
3) right and left triangular attach to tendinous region of the diaphragm


hepatorenal ligament, round ligament and less omentum what connect and what is important about the round ligament

hepatorenal - caudate process to the ventral surface of the right kidney
round - slight thickening of the caudal free edge of the falciform ligament
Differentiates between left medial lobe and quadrate lobe
lesser omentum - from visceral surface of liver to stomach (hepato-gastric) and duodenum (hepato-duodenal)


the bile duct system what flows into what

1) microscopic canaliculi
2) larger ductules
3) large hepatic ducts
4) common hepatic duct
- leads to cystic duct which connects to gall bladder
5) distal to cystic duct is common bile duct that runs into the duodenum entering on major duodenal papilla


gall bladder where positioned and what is special about the cystic duct

lies between the quadrate lobe medially and the right medial lobe laterally
bile can flow through the cystic duct in both directions.


blood supply to the liver

hepatic artery (branch of the celiac artery) - source of O2 and the portal vein - source of nurtients and atrophic factors like insulin (dual)
all blood delivered is collecting by central veins of hepatic lobules that drain into sublobular veins that drain into large hepatic veins that eventually drain into the caudal vena cava to the right side of the heart


The endodermal cells of the hepatic diverticulum differentiate into:

- Hepatocytes (liver cells) and the bile duct system and gall bladder
- Mesodermal cells of the septum transversum contribute to blood vessels - grows to the diaphragm
- Blood stem cells from the yolk sac migrate into the liver to form blood islands, which form blood cells.
(Thus at an early stage of development the liver is haemopoietic).


dog liver why isn't ventral border palpable, how many lobes and what lobe is special

presence of fat in the falciform ligament.
- It is deeply divided into five chief lobes by fissures extending from the ventral margin.
- The centrally located papillary process, which protrudes from its dorsal part, is the most prominent feature of the visceral surface.


gall bladder of the dog what surface see and what does discharge depend on

Always appears at the visceral surface
discharge of bile depends on the activity of the duodenum. The sphincter of Oddi is a smooth muscle sphincter at the termination of the bile duct with the duodenum.


horse liver what does axis run along, what is highest and lowest point, can it be palpated, what plane does it lay in and on what side

long axis runs obliquely.
Its highest point is at the level of the right kidney and its lowest point on the left side
Cannot be palpated
2/3 lies to the right of the median plane


what does the horse liver lay against on visceral surface and describe the lobes

lies against the stomach, the duodenum, dorsal diaphragmatic flexure of the colon and the caecal base
1) Right lobe is the largest-irregularly quadrilateral in form on its dorsal part is the caudate lobe and process. - doesn't have medial right lobe just all right lobe
2) Quadrate lobe is located between the right lobe and the falciform ligament which separates it from the left lobe.
3) The left lobe consists of a medial and lateral portion-lateral part is oval in outline and thickest centrally.


horse gall bladder

NO GALL BLADDER, but duct system is wider to compensate.
Bile duct opens into the cranial duodenum on the papilla shared with the major pancreatic duct, about 13-15 cm distal to the pylorus - known as the hepatopancreatic ampulla.


cow liver what contact, where sit and what is dorsal and what is ventral due to what

in contact with the right abdominal wall
entirely to right of median plane
the right lobe is dorsal and the left lobe is ventral - due to compound stomach on left hand side


the visceral surface of the cow liver what is it related to and what important structure sits here

is related to the reticulum, ruminal atrium, omasum, duodenum, gall bladder and pancreas
e is related to the reticulum, ruminal atrium, omasum, duodenum, gall bladder and pancreas.


lobes of the cow liver and the gallbladder

no distinct patterns of liver lobulation just left and right lobe
gallbladder protudes from the right lobe of the liver


the sheep and goat liver

resemble cattle but smaller and lobes more distinct


lobes of the pig and what makes it distinct

Left lateral (largest)
caudate lobe - doesn't make contact with kidney so no renal impression
left medial
no papillary process
short quadrate lobe
lateral and medial right lobe
high content of interlobular fibrous tissue outlines the lobules


birds liver what lobes present and what surfaces

birds lack diaphragm so embrace caudal process of the heart
larger right lobe - gall bladder
left lobe divided into deep fissue into caudoventral and caudorsal parts
- parietal surface is convex and lies against the sternal ribs and sternum
The cranioventral part of the parietal surface is concave where the lobes make contact with the apex of the heart.
The visceral surface is concave and makes contact with the spleen, proventriculus, gizzard, duodenum, jejunum and ovary.


gallbladder in birds

- Two bile ducts one from each lobe enter the distal end of the duodenum close to the pancreatic ducts.
- Only the duct from the right liver lobe is connected to the gall bladder.
- The pigeon, budgerigar and some parrots lack a gall bladder.


capsule of liver what made of, what blood vessels involved and what lined with

thin connective tissue capsule
sinusoids - Specialised blood channels little bigger than capillaries extend between cords of liver cells:
These are lined by endothelial cells and Kupffer cells - phagocytic cells


what are the specialised cells in the liver

Stellate cells
- are pericytes, found around the sinusoids just under the endothelium,
- Function - produce collagen - more important in disease processes