Histology of the Liver Flashcards
liver location
largest internal organ/gland
upper right quadrant of abdomen
below the diaphragm
hepatic lobules, what are they
polygonal structures
basic functional units
blood supply to the liver
dual
hepatic artery and heptic portal vein
has supply of oxygenated and deoxygenated blood
liver lobes
major left and right
2 smaller inferior lobes
composition of blood supply to the liver
75% nutrient rich but O2 poor
25% supplies O2
Glissons capsule
Layer of connective tissue surrounding the liver
subdivides the parenchyma into lobules
main components of bile
water
bile salts
bilirubin
cholesterol
fatty acids
electrolytes
main functions of the liver
exocrine funciton
endocrine function
metabolism and detoxification
storage
exocrine function
secretion of bile into the duodenum
help digest fat
eliminate waste products: bilirubin and excess cholesterol
endocrine function
synthesis of majority of plasma proteins: fibrinogen, prothrombin, lipoproteins and albumins
and their release into the bloodstream
metabolism and detoxification
breakdown of proteins
toxic substances
many drugs
oxidation and conduction of toxins and other hormones
elimination via bile or urine
storage
iron
blood
glycogen
triglycerides
vitamin A
where does the hepatic portal triad enter
periphery of each lobule
where does the terminal hepatic venule enter
centre of the lobule
aka centralvein
corners of the polygonal classic lobule
portal triad
components of the portal triad
portal vein
hepatic artery
bile duct
(small lymphatic vessels)
label the image
bile flow VS blood flow
opposite directions
where does blood flow in the liver
branches of hepatic artery and vein empty into hepatic sinusoids
flows towards central vein
lining of the sinusoids
discontinuous
separated from radial plates of hepatocytes by space of Disse
bile canaliculi
receive bile from hepatocytes that border them
convey it to bile ducts in portal triads
hepatic microcirculation
portal triad
sinusoidal system
sinusoid lumina
terminal hepatic venule (central vein)
sinusoidal system
interconnecting system of capillary like channels
close contact with hepatocytes
central venues convergence
into larger veins
eventually form 2 or more large hepatic veins
empty into inferior vena cava
label the hepatic microcirculation
what are the bile canaliculi
enlarged intercellular spaces
between 2 adjacent hepatocytes
where do hepatic sinusoids carry blood to
glucose rich and oxygen rich
to hepatocytes
through space of Disse
what is the space of Disse
between endothelial cells of hepatic sinusoid and hepatocytes
label the image
hepatocytes
large
polyhedral
spherical nuclei, often binucleated
acidophilic cytoplasm
sER, rER
lots of mitochondria
peroxisomes
multiple small Golgi
form plates/cords in liver
store glycogen
what is in the image
hepatocyte
B- binucleate hepatocyte
S- sinusoid lining cell
what occurs at periphery of each hepatic lobule
many bile canaliculi join with bile canals of Hering
bile canals of Hering
cuboid epithelial cell lining
called cholangiocytes
cholangiocytes
allow bile modification
where do bile canals of herring join and drain
join bile ductules in portal areas
drain into biliary tree
cholecystokinin funciton
hormone
regulates bile release from liver and gall bladder
causes gall bladder contraction and expansion of bile
where does cholecystokinin come from
enteroendocrine cells in intestinal mucosa
releases as fats in chyme
bile ductules pathway
canaliculi
canals of herring
bile ductules
bile duct
label bile ductule
Ito cell funciton
vitamin A storage
supporting cells
Kupffer cells
stellate macrophages
antigen presenting cells
remove worn out red blood cells
recycle iron molecules
remove bacteria/debris in portal blood
cytoplasm in hepatocyte
acidophilic
basal surface of hepatocytes
contact with perisinusoidal space of Disse
apical surface of hepatocytes
connected to adjacted hepatocyte
form bile canaliculus
what is in the image and label
PV - Portal vein
B - Bile ductules
A - Hepatic artery
L - lymphatics
H - Hepatocytes
S - Sinusoids
lymphatics in histology
present in total traces
walls are delicate and often collapsed
less easily identified
what surrounds the portal tract
anastomosing plates of hepatocytes
called hepatic sinusoids
3 ways to describe structure of the liver as a functional unit
classic lobule
portal lobule
liver acinus
classic lobule shape
polygonal
portal lobule shape
triangular
liver acinus she
diamond
3 zones and correlates to blood perfusion, metabolic activity and liver pathology
label the image of liver organisation
short axis of the acinus
defined by the terminal branches of portal triad
lie along border between 2 classic lobules
long axis of acinus
line drawn between 2 central veins closest to the short axis
hepatocyte arrangement in liver acinus
3 concentric elliptical zones
zone 1 acinus
periphery of classic lobules
closest to short axis and blood supply from penetrating branches of portal vein and hepatic artery
zone 2 acinus
between zones 1 and 3
no sharp boundaries
zone 3 acinus
most central part of classic lobule
surrounds terminal hepatic vein
furthest from short axis
describe images
a. hepatocytes
b. reticulin along plates of hepatocytes
c. central vein, more collagen than smaller sinusoids
d. peripheral portal areas with more connective tissue, site of portal triad
what is the gall bladder
hollow organ
inferior to the liver
function of gall bladder
store and concentrate bile
where is bile produced
liver hepatocytes
connections of gall bladder
to liver and duodenum
by biliary duct system
organ drains through cystic duct
joins common hepatic duct
forms common bile duct
how is bile released
in response to fats in duodenum
due to cholecystokinin
how does bile enter the duodenum
sphincter muscles relax
gallbladder contacts
forces bile in
function of bile acids and salts
emulsify lipids in duodenum
promote digestion and absorption
bile flow
leaves liver in left and right ducts
merge to common hepatic
connects to cystic duct that serves gall bladder
these ducts merge to form common bile duct
where does the main pancreatic duct merge with common bile duct
hepatopancreatic ampulla
where does the hepatopancreatic ampulla enter duodenum
at major papilla of Vater
where does the hepatopancreatic ampulla enter duodenum
at major papilla of Vater
where does the accessory pancreatic duct enter the duodenum
minor papilla
what mixes before releasing into the duodenal lumen
bile and pancreatic juices
layers of the wall of the gall bladder
mucosa
muscularis propria
serosa
label the image of the gall bladder
what reduces the volume of the gall bladder
contractions of the muscularis externa
forces bile out through the cystic duct and common bile duct
lining of hepatic, cystic and common bile duct
mucous membrane
simple columnar epithelium of cholangiocytes
apical histological surface of the gall bladder
simple columnar epithelial cells
many microvilli
lamina propria gall bladder
highly cellular
connective tissue
scattered smooth muscle cells from musculris
muscularis gall bladder
circular smooth muscle bundles, longitudinal and oblique random orientation
intervening connective tissue and blood vessels
outer layer gall bladder
thick fibrous connective tissue
contains nerves, blood and lymphatic plexus
externally covered by peritoneum so called srrosa
extra hepatic bile ducts
contain all layers of gall bladder wall
lined by epithelium similar to gall bladder
name of gall stones
cholelithiasis
components of gall stones
often solid deposits of cholesterol or calcium salts
symptoms and treatment of gall stones
no symptoms
can cause jaundice due to blocked bile flow
laparoscopic surgery
biliary colic
severe abdominal pain
gallstones risk factors
female
obesity
oral contraceptives
complications of gallstones
acute or chronic cholecystitis
blockage of ampulla of Vater so may lead to acute pancreatitis
cholecystitis
gall bladder contracts more strongly to try overcome obstruction
musculature thickens consequently
high pressure in gall bladder lumen
pushes pouches of mucosa into muscle layers
jaundice
yellow discolouration of tissues due to increased levels of bilirubin and associated deposition of bile pigments
bilirubin
Bilirubin is yellowish pigment that is made during the normal breakdown of red blood cells. Bilirubin passes through the liver and is eventually excreted out of the body.
hyperbilirubinaemia
(raised blood level of bilirubin)
classifications of hyperbilirubinaemia
prehaptic jaundice
hepatic jaundice
post hepatic jaundice/ obstructive jaundice
prehapetic jaundice
occurs due to increased production of bilirubin, such as when there is excessive red cell breakdown in sickle cell anaemia.
hepatic jaundice
occurs when there is acute or chronic damage to the liver, reducing its ability to metabolise and excrete bilirubin.
Posthepatic jaundice AKA obstructive jaundice
when there is some form of mechanical blockage which interrupts the flow of bile into the biliary system, such as gallstones.
