liver Flashcards
what is the largest gland in the body
liver
liver produces and secretes _____ which are important in ______
- bile salts and phospholipids
- fat digestion in the SI
the liver detoxifies and excretes (in the bile)
a lot of different
hormones, drugs, toxins, as well as the products resulting from the breakdown of haemoglobin
the liver regulates levels of
of glucose, lipids and nitrogenous compounds in blood
the liver is a storage organ especially for
glycogen, vitamins and minerals
the liver also plays a role in protein ____
synthesis
in the fetus the liver is
blood forming
functions of liver summary (6)
- Produces & secretes bile salts & phospholipids → fat digestion
- Detoxifies & excretes in bile
- Regulating levels of glucose, lipids and nitrogenous compounds in blood
- Storage organ for Glycogen, Vitamins and minerals
- In foetus – blood forming
- Protein synthesis
- she also lists as:
- detoxification of blood
- carbohydrate metabolism
- lipid metabolism
- protein synthesis
- secretion of bile
glucuronidation
what is it, what kind of bonds, why does it do this, what is it often involved in
- addition of glucuronic acid to substrate
- involve glycosidic bonds
- make substance water soluble and able to be excreted
- often involved in metabolism of foreign chemicals; xenobiotic metabolism
gall bladder function
stores and concentrates bile, releases bile into intestine
how much body weight is liver
1-5% BW
liver sits in ____ part of abdominal cavity
intrathoracic (the bit of the abdominal cavity that’s covered by the ribcage.)
parietal surface of liver
- Diaphragmatic surface (against diaphragm)
- Faces cranially
- Convex
Visceral surface
- Faces caudally
- Near right kidney, stomach, and intestine
- Concave
dorsal border of liver
- Rounded
- Crossed by oesophagus & CVC
other borders are thin and sharp
hepatic porta
- depression on visceral surface
- where the portal vein, hepatic artery, hepatic (bile) ducts, lymphatics and nerves pass.
surface of liver is covered by
- serosa (visceral peritoneum)
- Smooth, moist & slippery
- Allows diaphragm, other organs & lobes to move with little friction
name 2 ligaments that attach to the visceral (caudal) surface of the liver, what do they form
- Hepatogastric ligament to the lesser curvature of stomach
- Hepatoduodenal ligament to the proximal duodenum
- Together form the lesser omentum
name 4 ligaments that attach to the parietal surface
- Right & Left Triangular ligament
- Coronary ligament; Surrounds caudal vena cava, Between liver and caval foramen
- Falciform ligament, From umbilicus
right and left triangular ligaments
continuous with what and where do they attach
continuous medially with the coronary ligament.
They attach the right and left lobes of the parietal surface of liver to the diaphragm
the round ligament is remnant of the ______ and lies in the free
dorsocaudal border of the _____
- umbilical vein
- falciform ligament
why do we need to avoid cutting falciform ligament
where do you cut during routine surgery
contains a generous
amount of fat and will ooze blood when it’s cut
incise the abdomen caudal to the umbilicus to avoid the falciform ligament
Hepatorenal Ligament aka Caudate Ligament
caudate lobe —> region of right kidney
other than ligaments, what also provides significant attachment of the liver
The portal vein and the caudal vena cava
The ____ ligament is important in
every species except for the pig
caudate
The caudate process of the caudate lobe doesn’t reach the right kidney in the pig
the falciform and round ligaments are _____ attachments in every species
minor
the coronary ligament and the triangular ligament are
______ in every species
important
and the portal vein and caudal vena cava are ______ in attaching the liver in every species
very important
what imaginary line divides visceral surface of liver into Left and right lobes
oesophageal notch to round ligament
left and right lobes can be further divided in some species into
medial and lateral lobes
where do you find the quadrate lobe
- Between left and right lobes
- Divided from right by line from
CVC to gall bladder - Between gall bladder and left
medial lobe
caudate lobe location
what processes does it have
- Right visceral surface
- Dorsal to porta
- Caudate & papillary processes
- Caudate process reaches the right
kidney (hepatorenal aka caudate ligament)
cattle/ sheep liver lobes
- left and right not divided into medial and lateral
- quadrate normal
- caudate normal
- small papillary processes
horse liver lobes
- left M, left L, right lobe not divided into L and M
- quadrate fluted
- caudate normal
- no papillary processes
pig liver lobes
- Left M, left L, right M, right L
- quadrate; minor
- caudate normal, recall no caudate ligament bc caudate process doesn’t reach to kidney
- no papillary processes
dog/ cat liver lobes
- left M, left L, right M, right L
- quadrate normal
- caudate normal
- papillary process present
gall bladder of cattle/sheep
Extends beyond
ventral margin
gall bladder of horse
absent
gall bladder of pig
large
gall bladder of dog/cat
Extends to diaphragmatic
surface
position of liver in abdomen for dog/cats
- Almost symmetrical on mid-line
- Parietal strongly convex: Follows diaphragm
- Gall bladder visible on both parietal and visceral surfaces (but more visible on visceral)
Hepatic Artery
- derived from the coeliac artery
- enters at the porta
- brings oxygen‐rich blood to the liver
hepatic portal vein
- enters at the porta.
- brings nutrient‐rich blood from the stomach (including ruminant stomachs), the small and large intestines, and the pancreas and spleen
The volume of blood in the portal vein is ____ times the volume of arterial blood entering liver. It is about ___ % of the total cardiac output
2-3x
10%
streamlining of blood in hepatic portal vein can occur which means:
however more commonly the arrangement of portal tributaries results in :
blood from one region might go preferentially to one
region of liver
turbulence and mixing of blood in the portal vein
order of blood flow from sinusoids (specialized capillaries found in the liver) to….
sinusoids to central veins, then through hepatic veins to the caudal vena cava at the cranio‐dorsal border of the liver
blood pathway
Blood flows from the hepatic portal vein into the liver. This vein carries nutrient-rich blood from the digestive organs.
Blood is distributed to the liver lobules. These are the functional units of the liver.
Blood flows through the sinusoids. Here, it comes into close contact with liver cells, allowing for the exchange of nutrients, waste products, and other substances.
Blood collects in the central vein. This is the central vein of each liver lobule.
Central veins merge to form the hepatic vein. The hepatic vein carries blood out of the liver.
The hepatic vein empties into the caudal vena cava. This large blood vessel carries blood back to the heart.
Portosystemic shunts
- Failure of foetal hepatic circulation to convert to adult configuration
- Foetus – blood from placenta bypasses liver and enters circulation via the ductus venosus
- Failure of ductus venosus closure results in an intrahepatic shunt
liver main epithelial cells
hepatocytes
hepatocytes
- epithelial cells of liver
- mainly pentagonal or hexagonal, arranged plates
hepatocytes extend from the peripheral periportal areas to the
central veins
central veins drain to the
hepatic veins
Sinusoids carrying blood from both the hepatic artery as well as the hepatic portal vein converge on
central veins
Plates of cells (hepatocytes) radiating out from central vein form a unit called a
with edges known as
lobule
periportal regions
- clear in pig, not so much in other species
what do the periportal areas contain (recall they are the periphery of the lobules)
contain terminal branches ‐ arterioles ‐ of the hepatic artery and hepatic portal vein, but also contain
bile ductules, lymphatics, nerves and some connective tissues
portal triads
combo of the 3 vessels: hepatic artery, hepatic portal vein and bile ductules found in corners where multiple lobules meet
Branches of the hepatic artery carry
oxygenated blood to the hepatocytes
branches of the portal vein carry
blood with nutrients from the intestines
The bile duct carries bile products
away from the hepatocytes, to the larger ducts and gall bladder
classic lobule vs portal lobule vs hepatic acinus (all basically same thing just diff ways of describing, see pic on slide 36-38)
- hexagonal, plates of cells surrounding a central vein
- triangular (basically describing same thing but the 3 point of triangle are the central vein of 3 classic lobules and the centre is the corner where the 3 lobules meet ie the portal triad)
- diamond shaped, two points of diamond are two central veins, has 3 zones, zone 1 is innermost or periportal (which makes sense because its center of acinus is actually periportal area of 2 lobes), zone 2 is transition and zone 3 is pericentral
hepatic acinus (see pic slide 38)
zone 1: periportal, closest to arterioles, predominantly where oxidative metabolism occurs (gluconeogenesis, protein syntheses)
zone 2: midzonal/ transitional
zone 3; centrilobular or pericentral; poorest blood, reduction processes predominate, closest to blood drainage point at central vein
sinusoids
large irregular capillary like vessels from periportal to central vein
the gaps in the walls of sinusoids allows
nutrients/metabolites in the blood to
pass through to the Space of Disse and hepatocytes for processing
walls of sinusoids consists of
flattened endothelial cells, phagocytic Kupffer cells and occasionally interstitial fat storing cells
in a sinusoid from out to in (so from portal venule and hepatic arteriole towards central vein) what percent of blood is venous and what percent is arterial
75% from portal vein
25% from hepatic artery
describe a hepatocyte
- Typical “factory” cell (produce & transport protein)
- Smooth & granular ER
- Mitochondria
- Golgi apparatus
- Stores of fat and glycogen
- Produces bile
the hepatocyte surface which faces the sinusoid is covered by _____ which
microvilli
project into the interstitial fluid within the Space of Disse.
Hepatocytes produce _____ which is
secreted into _____
bile
bile canaliculi
bile canaliculi
Where the surface of the hepatocyte faces adjacent cells, it’s
fused at intervals to form a network of tiny tubules. These tiny tubules are the bile canaliculi, into which bile constituents are secreted
are there terminal lymphatics within liver lobule
no
where are terminal lymphatics located
describe lymph pathway
periportal areas, converge to form larger vessels which emerge at the porta
from there lymph enters hepatic lymph nodes before reaching blood through thoracic duct
Some superficial lymphatics pass to the caudal mediastinal, and sternal lymph nodes. Lymph going this way enters the blood through
the right lymph ducts
Branches of the parasympathetic (vagus) and sympathetic nerves enter the liver at
the porta
biliary system
- Bile secreted into canaliculi
- Flows to periportal areas –> bile ductule with cuboidal epithelium
- Ductules converge to form hepatic ducts
- Carry bile to porta
the common hepatic duct is joined by cystic duct from the _____ to
form the bile duct draining to the _____
gall bladder
duodenum
Near the porta, the hepatic ducts unite to form
the common hepatic duct
The bile duct is lined by
tall columnar epithelium and contains mucus‐secreting cells. The wall also contains a small amount
of smooth muscle.
in some species like sheep the bile duct is joined by the pancreatic duct to form
common bile duct and enter duodenum
in some species like the cow the bile and pancreatic duct enter the duodenum
separately
the bile duct Passes obliquely through duodenal wall at major duodenal
papilla through
the Sphincter of Oddi: muscle that opens and closes to allow bile and pancreatic juice to enter duodenum
gall bladder is absent in
horse and rat
gall bladder Lies between
Quadrate and right lobes on visceral surface
gall bladder stores and concentrates
bile; releases into intestine
gall bladder eipthelium
tall columnar, surface microvilli
gall bladder mucosa often folded to form
mucosal bridges
in gall bladder under the epithelium, the lamina propria is made up of
smooth muscle, no distinct layers and no muscularis mucosae
gall bladder covered in
serosa
how does gall bladder modify bile
concentrating and removing some electrolytes
Presence of fat in the proximal duodenum stimulates production of ____
cholecystokinin CCK
Produced by the enteroendocrine cells of the duodenal mucosa
Presence of fat in the proximal duodenum stimulates production of cholecystokinin (CCK)
Produced by the enteroendocrine cells of the duodenal mucosa
This signals the gall bladder to
contract; expels bile into common bile duct, bile carried to duodenum
The process of glucuronidation is where glucuronic acid is added to compounds. This process makes substances more water soluble. Which major category of liver function does this process fall into?
Detoxification of blood
What is the primary function of the gall bladder?
Storage and concentration of bile
Which of the following statements regarding the liver is CORRECT?
A.
The visceral surface is concave, faces cranially, and is up against the diaphragm
B.
The parietal surface faces caudally, is convex, and is in close proximity to the right kidney, stomach, and intestine
C.
The hepatic porta is a depression on the visceral surface, where the blood supply to the liver, lymphatics, and nerves enter, and the bile duct leaves
D.
The dorsal border is rounded and is crossed by the oesophagus and the hepatic portal vein
The hepatic porta is a depression on the visceral surface, where the blood supply to the liver, lymphatics, and nerves enter, and the bile duct leaves
The caudate ligament is NOT an important attachment of the liver in which of the following species?
Pig
Which of the following attachments of the liver does the round ligament border?
Falciform ligament
Which of the following species has a single left AND right lobe of the liver?
A.
Horse
B.
Pig
C.
Sheep
D.
Cat
Sheep
On the visceral surface of the liver, which of the following lobes is divided from the right lobe by a line running from the caudal vena cava to the gall bladder, and sits between the gall bladder and the left medial lobe?
Quadrate lobe
The species of domestic animal that has a right medial AND a right lateral lobe of the liver is
A.
Horse
B.
Cow
C.
Sheep
D.
Pig
Pig
Which of the following statements regarding blood supply to the liver is INCORRECT?
A.
Blood supply to the liver enters at the porta
B.
Blood in the hepatic artery contributes ~25% of the total blood flow through the liver, and supplies oxygen-rich blood from the coeliac artery
C.
Blood in the hepatic portal vein contributes ~75% of the total blood flow, and supplies oxygen-rich blood from the stomach, intestines, pancreas, and spleen
D.
Blood in the hepatic portal vein contributes ~75% of the total blood flow, and supplies nutrient-rich blood from the stomach, intestines, pancreas, and spleen
C
The classical liver lobule is a model of which aspect of hepatic architecture?
Anatomical
Which of the following is NOT a component of the portal triad?
A.
Terminal branch of the hepatic artery
B.
Terminal branch of the hepatic portal vein
C.
Bile ductule
D.
Sinusoid
Sinusoid
Which of the following statements regarding the periportal zone is CORRECT?
A.
The periportal zone is closest to the blood drainage point (the central vein)
B.
The periportal zone has the poorest blood supply; this is where processes associated with detoxification mostly occur
C.
The periportal zone has the best blood supply, resulting in the area having the best nutrition and oxygenation; this is predominantly where oxidative metabolism occurs
D.
The periportal zone is the transition region, between the area of highest blood flow, and the blood drainage point
C.
The periportal zone has the best blood supply, resulting in the area having the best nutrition and oxygenation; this is predominantly where oxidative metabolism occurs
Which of the following is NOT a component of the walls of sinusoids?
A.
Flattened endothelial cells
B.
Interstitial fat-storing cells
C.
Bile canaliculi
D.
Phagocytic Kupffer cells
C.
Bile canaliculi
Which of the following is NOT a feature of hepatocytes?
A.
Microvilli
B.
Have bile canaliculi which store fat
C.
Produce bile
D.
Contain significant amounts of smooth and granular endoplasmic reticulum
B.
Have bile canaliculi which store fat
In which of the following species does the bile duct join the pancreatic duct to form the common bile duct?
Sheep
Which of the following layers is NOT present in the gall bladder?
A.
Tall columnar epithelium
B.
Lamina propria
C.
Muscularis mucosae
D.
Perimuscular connective tissue
C.
Muscularis mucosae
Presence of fat in the proximal duodenum stimulates production of cholecystokinin (CCK). This is produced by which of the following cells in the duodenal mucosa?
Enteroendocrine cells
