WEEK 8: Liver and kidney Flashcards
describe the structure of the liver.
parenchyma
connective tissue stroma
heptaic sinusoids - capillaries
perisinusoidal spaces of Disse (between sinusoids and hepatocytes
what is the functional tissue of the liver? How are they arranged?
hepatocytes arranged in hepatic plates - parenchyma
define the term “liver unit”
the smallest entity in an organ that can undertake all the functions of the organ
classical lobule
portal triad and liver acinus
higlight the distinctive features of the classical lobule, portal lobule and liver acinus.
classical lobule - hexagonal - the classic lobule view focuses on the blood supply and hepatic mass arrangement
portal lobule - triangular in shape - Portal lobules emphasize the afferent blood supply and bile drainage by the vessels of the portal triads.
liver acinus - a diamond shaped area - liver acinus encompasses the liver tissue that is served by a single terminal branch of the hepatic artery
what structures can be found in a Portal triad?
contains:
branches of the portal vein,
hepatic artery,
bile ducts,
and small lymhpatic vessels.
define the function and histological structure of hepatocytes
80% of the liver.
large, hexagonal cells with spherical nuclei, numerous mitochondria.
The basal surface has contact with perisinusoidal space of Disse, but apical surface is connected to adjacent hepatocyte.
what is the bile canalicus?
formed when apial surface of a hepatocytes is connected to adjacent hepatocyte
location and function of Kupffer cells.
“special” stellate sinusoidal macrophage. They remove foreign and recycle iron.
located in hepatic sinusoid.
location and function of hepatic stellate cells
reside in perisinusoidal spaces and are loaded with lipid droplets for storage of vitamin A.
location and function of cholangiocytes
epithelial cells that line the bile ducts
define the relationship between hepatic stellate cells - myofibroblast - excessive collagen deposition in liver fibrosis
Cirrhosis (scarring of the liver) is caused by alcohol, hep B, hep C and non-alcoholic fatty liver disease.
Hepatocytes are dying and lose proteins, these are picked up by hepatic stellate cells and which become activated.
Kupffer cells produce growth factors and cytokines and also activate HSC.
Become myofibroblasts.
Fibrosis - damaged cells are slowly replaced w scarred tissue made up of collagen.
Cirrhosis is fibrosis along with high proliferation of hepatocytes which causes degeneration of necrosis of the.
what is the space of Disse?
a location in the liver between a hepatocyte and a sinusoid. Microvilli of hepatocytes extend into this space, allowing exchange of materials between liver cells and sinusiods.
describe the flow of bile.
bile canaliculi
canals of Hering
intrahepatic bile ductule
interlobular bile ducts
left and right hepatic ducts
common hepatic duct
gallbladder
bile duct
duodenum
what happens to hepatic stellate cells in pathologic conditions?
they’re activated and differentiate into myofibroblasts.
how do Kupffer cells activate HSC?
Kupffer cells produce growth factors and cytokines and also activate HSC.
which 2 ways are HSC activated? What do they turn into?
Kupffer cells produce growth factors and cytokines and also activate HSC.
Hepatocytes are dying and lose proteins, these are picked up by hepatic stellate cells and which become activated.
They become myofibroblasts.
how does a pathologist identify cirrhosis?
thick bands of mature fibrous tissue
nodules of ‘regenerative’ hepatocytes
what are primary tumours in the liver known as? Who is at high risk?
hepatocellular carcinoma
mostly occurs in people with cirrhosis of the liver
give some laboratory investigations for liver diseases.
liver function test or imaging with MRI
biopsy with special stains
what causes obstructive jaundice?
narrowed or blocked bile duct or pancreatic duct, preventing the normal release of bile into the intestines.
what stains are used for the liver? What do they stain exactly?
ferric iron (haemosiderin)
retic (reticulin fibres)
Van Gieson (collagen, bile)
PAS/D.PAS (glycogen)
what does the urinary system consist of?
2 kidneys, 2 ureters, bladder, urethra
what happens in urine production?
kidney control acid-base balance
eliminate waste products of metabolism
excrete excess water
2 hormones in endocrine function - what are they for?
erythropoietin (erythrocyte production)
renin (blood pressure control)
what is the kidney divided into?
capsule
cortex
medulla
pelvis
identify sections of the nephron and different epithelial cell types found
glomerulus, Bowman’s capsule, loop of Henle, connecting duct, proximal convuluted tubules, distal convoluted tubules
what are the location and function of macula dense and juxtaglomerular cells
jux - maintain blood pressure and act as a quality control mechanism, regulate function.
what are medullary rays?
located in the renal cortex
bundles of renal tubules essential for the transportation of water and other substances in the kidney
where can we find transitional epithelial in the kidney and why?
it lines the structures of the urinary system.
it prevents microbial adherence to the bladder epithelium
identify the different sections of the arterial and venous system of the kidney.
Oxygenated blood comes to the kidneys from the right and left renal arteries off the abdominal aorta. Deoxygenated blood leaves the kidneys via the right and left renal veins that run into to the inferior vena cava
identify applications of common special stains in the kidney.
H+E - proximal ct are v positive, distal ct are less positive, collecting ducts have a low staining
where can we find the basement membrane in the Glomerulus and how is it changed in membranous Glomerulonephritis?
what are 4 major renal processes?
glomerular filtration
tubular reabsorption
tubular secretion
excretion
layers for glomerular filtration
fenestrated endothelium
basement membrane
filtration slit made up by cells called called podocytes
what is the histology of the proximal convoluted tubule?
simple cuboidal epithelium
intensely eosinophilic (these cells take up material to be recycled)
prominent brush border
what is the histology of the loop of Henle?
simple squamous epithelium
highly permeable to water, urea, ions
what is the histology of the distal convoluted tubule?
simple cuboidal epithelium
weakly eosinophilic
low brush border
impermeable to water/urea
what is the histology of the collecting tubules/ducts?
simple cuboidal epithelium
pale cytoplasm
prominent lateral cell boundaries
