Liver and gallbladder histology

Question 1

Liver tissues

Answer 1

parenchyma, stroma, sinusoids

Question 2

Liver parenchyma

Answer 2

plates of hepatocytes, one cell thick

Question 3

liver stroma

Answer 3

CT with vessels, nerves, lymphatics and bile ducts

Question 4

liver sinusoids

Answer 4

capillaries between the plates (specialized type of capillary, looks like white lines between the hepatocytes)

Question 5

Liver structure: lobule

Answer 5

hexagonal stack of parenchyma, separated by sinusoids.

Blood arises from portal veins and hepatic arteries surrounding lobule and drains in central vein

Question 6

Portal canals:

Answer 6

found at the angle of the hexagon, made of stroma, contain the portal triad

Question 7

Portal triad

Answer 7

: hepatic artery, portal vein, bile duct

Question 8

Acinus

Answer 8

Smaller functional unit of the lobule (one per side)
Triangle-shape formed by the central vein and two portal canals
Arranged in zones, relevant to pathology
Zone 1: Closest to the blood supply, near portal canal
Zone 2: In the middle
Zone 3: Farthest from the blood supply, near central vein

Question 9

Shape of hepatocytes

Answer 9

large and polygonal

Question 10

nucleus of hepatocytes

Answer 10

large, central nucleus. Many are binucleate, distinct heterochromatin clumps, up to 2 nucleoli or even nuclei per cell

Question 11

Cytoplasm of hepatocytes

Answer 11

pink or acidophilic. Glycogen (seen with PS), 
lipid droplets (present in variable amounts, increase after exposure to hepatotoxins- ethanol, e.g.), 
peroxisomes (large and numerous, cannot be seen with H&E, need immunohistochemistry

Question 12

Hepatic sinusoids: endothelium

Answer 12

discontinuous. Basal lamina absent in large areas, large fenestrae present.

Question 13

Hepatic sinusoids: Kupffer cells

Answer 13

mononuclear phagocytes present in the sinusoidal endothelium.
In hemosiderosis or hemochromatosis, identified by iron deposits within

Question 14

Liver: perisinusoidal space

Answer 14

= Space of Disse
The space between the sinusoidal endothelium and hepatocytes
No real barrier because of incomplete basal lamina–> free flow of proteins
Blood forming colonies existed here in the fetus and can be present in adults with chronic anemia.
Ito cells here

Question 15

special ability of fibroblasts

Answer 15

dedifferentiate and redifferentiate

Question 16

Biliary tree

Answer 16

system of channels for bile. Aspects:
cholangiocytes
bile canaliculus
canal of hering
bile ductule
bile duct

Question 17

cholangiocytes

Answer 17

cuboidal to columnar epithelial cells that line these bile channels
complete basal lamina and tight junctions
apical microvilli and one primary cilium (sensory)

Question 18

Bile canaliculus

Answer 18

formed by grooves in the surface of adjacent hepatocytes

Question 19

Canal of Hering

Answer 19

formed by hepatocytes and cholangiocytes

Question 20

bile ductule

Answer 20

formed entirely by cholangiocytes

Question 21

bile duct

Answer 21

part of the portal triad

Question 22

Describe the parts of the portal vein (triad)

Answer 22

Portal vein- largest, thin wall
Hepatic artery- arteriole wall, thicker
bile duct- simple cuboidal or columnar epithelium
lymphatics- thinnest wall, often collapsed.

Question 23

Gall bladder

Answer 23

pear-shaped, blind-ending sac

Question 24

gall bladder mucosa

Answer 24

simple columnar epithelium- closely resemble absorptive cells of the intestine (apical microvilli present, tight junctions between cells)

lamina propria- fenestrated capillaries, highly cellular (large number of lymphocytes, no lymphatic vessels), mucous-secreting glands

Muscularis mucosae is absent in the gall bladder
submucosa also absent

Muscularis externa- smooth muscle bundles: random orientation, contraction empties contents into cystic duct.

Adventitia- attached to liver, Serosa (free surface)
– dense connective tissue,

Question 25

Ito cells (hepatic stellate cells)

Answer 25

• storage site for Vitamin A, can differentiate into a myofibroblast and cause fibrogenesis in disease