Histology Of The Liver Flashcards
The liver is ——g in weight
1500
List 10 functions of liver
- Conversion excess glucose into glycogen and vica versa in need.
Gluconeogenezis. - Progressing hemoglobin for use of its iron, storing iron and cupper.
- Production of bile which helps
carry away waste (ie. bilirubin) and break down fats in the small
intestine during digestion. - Production and conversion of signal
molecules and hormones.
(erytropoetin, angiotensinogen, hepcidin, IGF1,2, trijodtyronin). - Resisting infections by producing immune factors and removing
bacteria from the bloodstream. - Clearing the blood of drugs and other
poisonous substances. Conversion of poisonous ammonia tourea. - Production of plazma proteins (albumin, fibrinogen, blood coagulation factors, transferrin).
- Regulation of blood levels of amino acids.
- Organization of lipid metabolism production of cholesterol.
- Storage of vitamins (A, B12, folic acid).
Blood Supply
■ Input:
■ —% portal vein
■ (poor/rich?) in oxygen
■ rich in ———
Dual Blood Supply
■ Input:
■ 75% portal vein
■ poor in oxygen
■ rich in nutritions and pancreatic hormones ( from the bowels),
■ rich in hemoglobin metabolites-bilirubin and heme (from the spleen)
Blood Supply
■ Input:
■ • —% hepatic artery
■ rich in ——
■ Output:
—— veins → drain into ——
Blood Supply
■ Input:
■ • 25% hepatic artery
■ rich in oxygen
■ Output:
■ hepatic veins → inferior vena cava
STRUCTURAL ORGANIZATION include
STRUCTURAL ORGANIZATION
Parenchyma
Connective tissue stroma
Sinusoidal capillaries (sinusoids) Perisinusoidal space (space of Disse)
CAPSULE
• The liver is enclosed in a capsule of fibromuscular connective tissue known as —— capsule.
• (Thin/thick ?) capsule
CAPSULE
• The liver is enclosed in a capsule of fibromuscular connective tissue known as Glison’s capsule.
• Thin capsule
LIVER LOBULES include:
LIVER LOBULES
■ Classic/Hepatic Lobule ■ Portal Lobule
■ Liver Acinus
Hepatocytes:
■ main cell type in the parenchyma(—%)
■ explain its nuclei
■ —— cells are common ((paired/unpaired?) nuclei)
Hepatocytes:
■ main cell type in the parenchyma(80%)
■ have large, round euchromatic nuclei, and one or more nucleoli
■ binucleate cells are common (paired nuclei)
HEPATOCYTES
■ Polyhedral cells —— to ——μm
■ (Eosinophilic/basophilic?)
■is the nucleus binucleate?
■ presence of——junctions between hepatocytes
■ Hepatocyte surfaces related to:
HEPATOCYTES
■ Polyhedral cells 20-30μm
■ Eosinophilic
■ Large nucleus /binucleate
■ Bile canaliculi
■ Gap junctions between hepatocytes
■ Hepatocyte surfaces related to:
■ Perisinosoidal space
■ Adjacent hepatocyte
■ Bile canaliculi
HEPATOCYTES
Nucleus
■ Prominent nucleolus
■ Disperse ——
■ exhibit polyploidy T or F
Cytoplasm
■ ——— appearance
■ ——— vacoules
■ Ribosomes & RER- (basophilia/eosinophilia?)
Mitochondria-(eosinophilic/basophilic?)
List other organelles that can be found
HEPATOCYTES
■ Nucleus
■ Prominent nucleolus
■ Disperse chromatin
■ Polyploidy
■ Cytoplasm
■ Glycogen-lacey appearance
■ Fat-spherical vacoules
■ Ribosomes & RER- basophilia
■ SER
■ Mitochondria-eosinophilic
■ Lysosomes
■ Golgi complex
■ Peroxisomes
FINE STRUCTURE OF HEPATOCYTES
■ Rough endoplasmic reticulum –function:
■ Smooth endoplasmic reticulum – function:
■ Golgi apparatus – near nucleus function:
FINE STRUCTURE OF HEPATOCYTES
■ Rough endoplasmic reticulum – protein synthesis
■ Smooth endoplasmic reticulum – oxidation, methylation
■ Conjugation of bilirubin to gluronate – bilirubin glucoronide
■ Synthesis of bile acids
■ Golgi apparatus – near nucleus
■ Formation of lysomes
■ Secretion of proteins, glycoproteins, lipoproteins into plasma
FINE STRUCTURE OF
HEPATOCYTES
■ Lysosomes –function:
■ Mitochondria
■ Peroxisomes- function:
FINE STRUCTURE OF
HEPATOCYTES
■ Lysosomes –turnover & degradation of organelles
■ Mitochondria
■ Peroxisomes –
■ Important for oxidation of excess fatty acid
■ Breakdown of hydrogen peroxide
■ Breakdown of purines to uric acid
■ Synthesis of cholestrol, bile acids & some lipids for myelin
■ Drug inactivation –by enzyme glucuronyle transferase
bile canaliculi between the adjacent hepatoctes:
-formed by ——-
-sealed by ———on the two sides
bile canaliculi between the adjacent hepatoctes:
-formed by plasma membranes
-sealed by tight junctions on the two sides
What is the shape of the cell
Polyhedral cells
Hepatic lobule
—— shaped functional unit consisting of mainly hepatocytes.
Lobules are separated by connective tissue – ———
Branches of the ——, the —— and the ——— follow at the corners of the hexagon and are called ———
Hepatic lobule
Hexagonal shaped functional unit consisting of mainly hepatocytes.
Lobules are separated by connective tissue – interlobular septa.
Branches of the portal vein, the hepatic artery and the hepatic duct follow at the corners of the hexagon
and are called portal triad.
Hepatic lobule
• Blood flows from the periphery of the lobule toward the ———
• In the center of the hexagon there is a ——-.
• The central (=also called———) vein gathers blood and
transports it to the ——— vein, and then into the —— vein.
Hepatic lobule
• Blood flows from the periphery of the lobule toward the center (red arrows).
• In the center of the hexagon there is a central vein.
• The central (=centrilobular) vein gathers blood and
transports it to the sublobular vein, and then into the hepatic vein.
——are dilatatedcapillaries. Blood from the perilobular vessels falls into the sinusoids and from them to the central vein.
Sinusoids
Arterial and venous blood get mixed in the ——. Sinusoids separate the —-.
They form anastomoses, thus at least two surfaces of a hepatocyte is
surrounded by blood.
. Arterial and venous bloodg e t mixed in the sinusoids. Sinusoids separate the hepatic plates.
They form anastomoses, thus at least two surfaces of a hepatocyte is
surrounded by blood.
Hepatic cells in the lobule form——— plates.
W i t h i n the plates hepatocytes
are arranged in —— cords. •The cords are actually branching,interconnected sheets.
On cell layer thick plates
Radial cords
Portal triad is also called
Glisson’s triad
Perilobular vein is a Lateral branch of the
——— vein.
Lateral branch of the
interlobular vein.
perilobular artery
Lateral branch of the ——— artery.
perilobular artery
•
Lateral branch of the interlobular artery.
——— is a network of fine arteries.After supplying the interlobular duct joins to the sinusoids.
peribiliary plexus
•
Network of fine arteries.
•After supplying the interlobular duct joins to the sinusoids.
capsule of the liver
• Contain
capsule
• Contain connective tissue
Portal triad
interlobularartery
> —- or —— shape
> muscular media
may contain ———
interlobularartery
> round or oval shape > muscular media
may contain red blood cells
Portal triad
lymphvessel
> ——- shape
> very delicate —-
> no——-
lymphvessel
> irregular shape
> very delicate wall > no red blood cells
Portal triad
interlobular bile duct
> —— or —— shape
> ———— epithelium for the small ones
> or ———— epithelium for the larger ones
interlobular bile duct > round or oval shape
> simple cuboidal (small ones) > or columnar (larger ones)
epithelium
Portal triad
interlobular vein
• ——- shape
> thin wall, only endothelial lining
> surrounding ——- may contain red blood cells
interlobular vein
• irregular shape
> thin wall, only endothelial lining > surrounding pericytes
may contain red blood cells
Portal lobule
■ Emphasizes ——— function
■ Includes those portions of three classical lobules that secrete —— that drains unto ———
Portal lobule
■ Emphasizes exocrine function
■ Includes those portions of three classical lobules that secrete bile that drains unto bile duct
Portal lobule
——— shaped with ——— at the center, ——— at the edges.
Triangular shaped with bile duct at the center, central veins at the edges.
Portal lobule
■ Bile canaliculi —- to —μm diameter
■ Limited by ———of hepatocytes
■ Canaliculi empty into bile ductules lined by ——- cells called ———
■ Direction of bile flow – opposite to that of ——
■ Bile canaliculi 1-2μm diameter
■ Limited by plasma membrane
of hepatocytes
■ Tight junctions
■ Canaliculi empty into bile ductules lined by cuboidal cells called cholangiocytes
■ Hering’s canals
■ Bile ducts –portal spaces
■ Right & left hepatic ducts
■ Direction of bile flow – opposite to that of blood
———- begin in the lobules, are lined partially by cholangiocytes and partly by hepatocytes, and conduct bile from bile canaliculi to terminal bile ducts in portal tracts.
The canals of Hering (CoH) begin in the lobules, are lined partially by cholangiocytes and partly by hepatocytes, and conduct bile from bile canaliculi to terminal bile ducts in portal tracts.
LIVER ACINUS based on ——- flow
Oxygen
Liver acinus
According to the deacreasing oxygen gradient toward the ——, the acinus is divided
into 3 zones. Hepatocytes in the zones have different functions.
Zone 1: what does it do -
Zone 3:what does it do-
Zone 2: —— zone
According to the deacreasing oxygen gradient toward the central vein, the acinus is divided
into 3 zones. Hepatocytes in the zones have different functions.
Zone 1: first to receive both nutrients and toxins
last to die in case of ishemia and the first to
regenerate
first to take up glucose to store as glycogen
first to show morphological changes following bile duct occlusion
Zone 3: first to show ischemic necrosis
first to show fat accumulation in obese persons
last to respond to toxic substances and bile stasis
Zone 2: intermediate zone
LIVER ACINUS
⚫ —— shaped area
⚫ how many portal triads
⚫ how many closest central veins
Based on nature of blood supply & O2 gradient
ZONE—- - nearest arteriole- most O2 & nutrients, oxidative metabolism
ZONE — –near central vein – least O2 & nutrients, glycolysis, lipid formation,ischemic necrosis
ZONE — – intermediate range
LIVER ACINUS
⚫ Diamond shaped area
⚫ Two portal triads
⚫ Two closest central veins
Based on nature of blood supply & O2 gradient
ZONE 1- nearest arteriole- most O2 & nutrients, oxidative metabolism
ZONE III –near central vein – least O2 & nutrients, glycolysis, lipid formation,ischemic necrosis
ZONE II – intermediate range
Zone —:
- gluconeogenesis
- oxidative energy metabolism
- urea synthesis
Zone —:
- glycolysis
- lipogenesis
Zone —: - display attributes of both zone I a n d III
Zone I:
- gluconeogenesis
- oxidative energy metabolism
- urea synthesis
Zone III:
- glycolysis
- lipogenesis
Zone II: - display attributes of both zone I a n d III
COMPARISON
CLASSIC HEPATIC LOBULE
Drains blood from the —— and the —- to the ——
PORTAL LOBULE
Drains —- from hepatocytes to the —-
PORTAL ACINUS
Supplies —— to ——
CLASSIC HEPATIC LOBULE
Drains blood from the portal vein and the hepatic artery to the hepatic or the central vein
PORTAL LOBULE
Drains bile from hepatocytes to the bile duct
PORTAL ACINUS
Supplies oxygenated blood to hepatocytes
Flow of blood from the interlobular vein to the hepatic vein
Interlobular-perilobular-central vein(centrilobular)- sublobular - hepatic vein
Blood vessels of parenchyma
Easy exchange of large molecules between hepatocytes and blood plasma is facilitated by :
-the sinusoidal wall is lined with ——endothelium,
-beside the intercellular fenestrae there are also ——— in the endothelial cells,
-the —— is discontinous or missing,
the hepatocytes and the sinusoidal wall is separated by the —— space – also called space of ——,
plasma may enter, but ——-and platelets are exluded form the perisinusoidal space,
-——-(increasing surface) of the hepatocytes extend into the space of Disse-this is the site of exchange.
Easy exchange of large molecules between hepatocytes and blood plasma is facilitated: the sinusoidal wall is lined with fenestrated endothel,
beside the intercellular fenestrae there are also intracellular pores in the endothelial cells,
microvilli (increasing surface) of the hepatocytes extend into the space of Disse-this is the site of exchange.
•
Kupffer cells: in t h e ——
Ito cells (hepatic stellate cells): in the ——
•
Kupffer cells: in t h e sinusoids
Ito cells (hepatic stellate cells): in the perisinusoidal space
Kupffer cells are Resident Macrophages
—— or —— shaped, smaller, migrating cells in the sinusoids
are part of the immune system – diffuse ———.
uptake effete erythrocytes and break down hemoglobin
store most of the iron in form of ——- - pigment
❖ hepatocytes store some iron in form of ——-
Kupffer cells are Resident Macrophages
triangular or star shaped, smaller, migrating cells in the sinusoids
are part of the immune system – diffuse mononuclear phagocyte system (MPS)
uptake and degrade foreign and potentially harmful substances
proliferate and enlarge in response to hepatocyte damage, bacterial toxins, etc.
uptake effete erythrocytes and break down hemoglobin
store most of the iron in form of hemosiderin - pigment
❖ hepatocytes store some iron in form of ferritin
Hepatic stellate cells (Ito cells)
hepatic stellate cell = also called —- cell = also called —— cell
located in the ———-
cannot be seen on —— stained
sections
strore and metabolize ——-
produce connective tissue of
interlobular septa
Hepatic stellate cells (Ito cells)
hepatic stellate cell = Ito cell = perisinusoidal cell
located in the space of Disse
cannot be seen on H&E
(hematoxylin and eosin) stained
sections
strore and metabolize vitamin A
produce connective tissue of
interlobular septa
Vitamin A in high doses is a direct toxin. Excess vitamin A is stored in stellate cells in the liver and accumulation can lead to their activation and hypertrophy, and causes ——-.
Vitamin A in high doses is a direct toxin. Excess vitamin A is stored in stellate cells in the liver and accumulation can lead to their activation and hypertrophy, excess collagen production, fibrosis and liver injury.
Due to the large pores or fenestrations in sinusoidal endothelial cells, fluid and proteins in blood flow freely into the space between the endothelium and hepatocytes (the “called the ——”), forming ——. Lymph flows through the space of Disse to collect in small lymphatic capillaries associated with portal triads
to the large pores or fenestrations in sinusoidal endothelial cells, fluid and proteins in blood flow freely into the space between the endothelium and hepatocytes (the “space of Disse”), forming lymph. Lymph flows through the space of Disse to collect in small lymphatic capillaries associated with portal triads
LIVER STEM CELLS (—- shaped cells)
■ Present in initial epitetlium of ——near portal areas
■ Can give rise to ——- & ——-
LIVER STEM CELLS (oval cells)
■ Present in initial epitetlium of bile ductules near portal areas
■ Can give rise to hepatocytes & cholangiocytes
