Histology of accessory organs Flashcards
The liver is a solid organ composed of tightly packed pink staining plates called
Hepatocytes.
collagenous capsule into the outer surface of liver -coverd by ?
mesothelial layer from the peritoneum
spaces that lie between hepatocytes
and are vascular seen, as pale-stained spaces between plates of liver cells.
Sinusoids
sinusoids form low resistance system of ……….
very channels allowing blood to be in contact with hepatocytes.
which tissue is found most in the portal tract, which contains what ?
collagenous tissue and contains main blood vessels running into liver.
a structure running in the portal tracts is
bile ducts.
Terminal hepatic venules .
are also called centrilobar venules which drain the liver and are tributaries of hepatic veins which shunt blood to the inferior vena cava.
hepatocytes
are large polyhedral cells with round nuclei, peripherally dispersed chromatin and prominent nucleoli. binucleate cells are common.
Cytoplasm has variable appearance
Brown granules of wear-and-tear pigment lipofuscin
what cells line the sinusoid ?
lined by flat endothelial cells which are distinguished by the flattened condensed nuclei.
small-diameter thick walled vessesls
are terminal branches of hepatic arteries.
Bile canaliculi
drains into bile-collecting ducts
is lined by simple cuboidal or columnar epithelium, and drains into bile ductules.
ductules emerge forming what structure and that structure drains into what?
larger trabecular ducts that drain via intrahepatic ducts into right and left hepatic ducts.
hepatocytes are collectively termed?
limiting plate, surrounding thebportal tract
hepatocytes are collectively termed?
limiting plate, surrounding the portal tract
hepatocytes are collectively termed?
limiting plate, surrounding the portal tract
Reticulin of the liver
maintains the structural integrity of the liver, in form of a meshwork of reticulin fibers (collagen type 3)
functions of reticulin
Supports hepatocytes and sinusoidal lining cells.
Merges with collagenous supporting tissue of portal tract and terminal hepatic venule.
At periphery of liver, reticulin is continuous with capsule that invests external surface of liver
sinusoids lining
they are lined by fanestrated
sinusoids lining
they are lined by fenestrated endothelium with no basement membrane, is separated from hepatocytes by narrow space which drains into lymphatics of portal tracts.
Hepatic vasculature.
Hepatic portal vein and hepatic artery branch repeatedly within liver
Terminal branches run within portal tracts and empty into sinusoids
Blood from both systems filters between plates of hepatocytes in sinusoids which then drain into terminal hepatic venule
Bile secreted into bile canaliculi between plasma membranes of adjacent hepatocytes
Then drains into system of bile ducts in portal tracts
name the structural unit of the liver ?
liver lobule.
Roughly hexagonal in shape, centred on a terminal hepatic venule
Portal tracts are positioned at angles of the hexagon
Blood from portal vein and hepatic arteries flows away from portal tract to adjacent central veins
a physiologically useful model of liver anatomy?
hepatic acinus.
a berry-shaped unit of liver parenchyma centred on the portal tract and lies between two or more terminal hepatic venules.
acinus.
blood flows from portal tracts through sinusoids to venules
irregular hexagonal boundary at lobule is defined by
portal tract and space collagenous tissue.
where do the sinusoids originate?
originate at lobule margin and course between plates of hepatocytes to converge upon terminal hepatic venule.
plates of hepatocytes are?
are generally one cell thick and branch and anastomose to form a three-dimensional sponge.
a muscular sac lined by simple columnar epithelium.
gallbladder
submucosa.
relatively loose, rich in elastic fibers, blood vessels, and lymphatics which drain water reabsorbed from bile during the concentration process.
The muscular layer wall of the gallbladder.
have fibers arranged in longitudinal, transverse and oblique orientations but do not form distinct layers.
a thick collagenous adventitial coat is present.
wall of the cystic Duct.
is formed into a twisted mucosa-covered fold which is known as the spiral valve of the heister.
the flow of bile and pancreatic juice into the duodenum is controlled by?
hepatopancreatic sphincter which also allows for the prevention of reflux of the bile and pancreatic juice.
lobulated gland covered by a thin collagenous capsule that extends as delicate septa between lobules.
pancreas
pancreas is what type of gland is
both exocrine and endocrine gland
exocrine component consists of closely packed acini which drains into a highly branched dust system.
endocrine tissue forms islets of Langerhans of various size that is scatted around / throughout the exocrine tissue drains into blood system.
Occasional adipocytes are scattered throughout parenchyma
pancreatic acinus
is comprised of an irregular cluster of pyramid-shaped secretory cells, the apex of which surrounds a tiny central lumen.
the smallest tributaries
known as intercalated ducts which drain into interlobar ducts in the septa of the gland
The intercalated ducts
lined by simple cuboidal epithelia which become stratified in larger ducts.
As the duct size increases, it becomes invested by a progressively thicker layer of dense collagenous tissue.
wall of main pancreatic duct has smooth muscle present.
The spleen
thin fibroelastic capsule has short trabeculae extending into parenchyma.
the splenic parenchyma
is dark red( red pulp) with small white nodules ( white pulp) scattered throughout.
Parenchyma permeated by interconnected network of sinuses (lined with endothelium) draining into larger sinuses which are tributaries of splenic vein
Red pulp
loose tissue
supported by reticulin fibers that are permeated by capillaries, some red pulp patches have no capillaries, instead have T and B lymphocytes.
the most common tumors arising in pancreas, usually arise from pancreatic duct epithelium.
pancreatic adenocarcinoma.
In the head of the pancreas, they would obstruct the common bile duct and result in painless obstructive jaundice
In the body and tail of the pancreas, they are difficult to detect and are mainly found in autopsy examinations
