WEEK 8: Liver and kidney

Question 1

describe the structure of the liver.

Answer 1

parenchyma
connective tissue stroma
heptaic sinusoids - capillaries
perisinusoidal spaces of Disse (between sinusoids and hepatocytes

Question 2

what is the functional tissue of the liver? How are they arranged?

Answer 2

hepatocytes arranged in hepatic plates - parenchyma

Question 3

define the term “liver unit”

Answer 3

the smallest entity in an organ that can undertake all the functions of the organ
classical lobule
portal triad and liver acinus

Question 4

higlight the distinctive features of the classical lobule, portal lobule and liver acinus.

Answer 4

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

Question 5

what structures can be found in a Portal triad?

Answer 5

contains:
branches of the portal vein,
hepatic artery,
bile ducts,
and small lymhpatic vessels.

Question 6

define the function and histological structure of hepatocytes

Answer 6

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.

Question 7

what is the bile canalicus?

Answer 7

formed when apial surface of a hepatocytes is connected to adjacent hepatocyte

Question 8

location and function of Kupffer cells.

Answer 8

“special” stellate sinusoidal macrophage. They remove foreign and recycle iron.
located in hepatic sinusoid.

Question 9

location and function of hepatic stellate cells

Answer 9

reside in perisinusoidal spaces and are loaded with lipid droplets for storage of vitamin A.

Question 10

location and function of cholangiocytes

Answer 10

epithelial cells that line the bile ducts

Question 11

define the relationship between hepatic stellate cells - myofibroblast - excessive collagen deposition in liver fibrosis

Answer 11

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.

Question 12

what is the space of Disse?

Answer 12

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.

Question 13

describe the flow of bile.

Answer 13

bile canaliculi
canals of Hering
intrahepatic bile ductule
interlobular bile ducts
left and right hepatic ducts
common hepatic duct
gallbladder
bile duct
duodenum

Question 14

what happens to hepatic stellate cells in pathologic conditions?

Answer 14

they’re activated and differentiate into myofibroblasts.

Question 15

how do Kupffer cells activate HSC?

Answer 15

Kupffer cells produce growth factors and cytokines and also activate HSC.

Question 16

which 2 ways are HSC activated? What do they turn into?

Answer 16

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.

Question 17

how does a pathologist identify cirrhosis?

Answer 17

thick bands of mature fibrous tissue
nodules of ‘regenerative’ hepatocytes

Question 18

what are primary tumours in the liver known as? Who is at high risk?

Answer 18

hepatocellular carcinoma
mostly occurs in people with cirrhosis of the liver

Question 19

give some laboratory investigations for liver diseases.

Answer 19

liver function test or imaging with MRI
biopsy with special stains

Question 20

what causes obstructive jaundice?

Answer 20

narrowed or blocked bile duct or pancreatic duct, preventing the normal release of bile into the intestines.

Question 21

what stains are used for the liver? What do they stain exactly?

Answer 21

ferric iron (haemosiderin)
retic (reticulin fibres)
Van Gieson (collagen, bile)
PAS/D.PAS (glycogen)

Question 22

what does the urinary system consist of?

Answer 22

2 kidneys, 2 ureters, bladder, urethra

Question 23

what happens in urine production?

Answer 23

kidney control acid-base balance
eliminate waste products of metabolism
excrete excess water

Question 24

2 hormones in endocrine function - what are they for?

Answer 24

erythropoietin (erythrocyte production)
renin (blood pressure control)

Question 25

what is the kidney divided into?

Answer 25

capsule
cortex
medulla
pelvis

Question 26

identify sections of the nephron and different epithelial cell types found

Answer 26

glomerulus, Bowman’s capsule, loop of Henle, connecting duct, proximal convuluted tubules, distal convoluted tubules

Question 27

what are the location and function of macula dense and juxtaglomerular cells

Answer 27

jux - maintain blood pressure and act as a quality control mechanism, regulate function.

Question 28

what are medullary rays?

Answer 28

located in the renal cortex
bundles of renal tubules essential for the transportation of water and other substances in the kidney

Question 29

where can we find transitional epithelial in the kidney and why?

Answer 29

it lines the structures of the urinary system.
it prevents microbial adherence to the bladder epithelium

Question 30

identify the different sections of the arterial and venous system of the kidney.

Answer 30

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

Question 31

identify applications of common special stains in the kidney.

Answer 31

H+E - proximal ct are v positive, distal ct are less positive, collecting ducts have a low staining

Question 32

where can we find the basement membrane in the Glomerulus and how is it changed in membranous Glomerulonephritis?

Question 33

what are 4 major renal processes?

Answer 33

glomerular filtration
tubular reabsorption
tubular secretion
excretion

Question 34

layers for glomerular filtration

Answer 34

fenestrated endothelium
basement membrane
filtration slit made up by cells called called podocytes

Question 35

what is the histology of the proximal convoluted tubule?

Answer 35

simple cuboidal epithelium
intensely eosinophilic (these cells take up material to be recycled)
prominent brush border

Question 36

what is the histology of the loop of Henle?

Answer 36

simple squamous epithelium
highly permeable to water, urea, ions

Question 37

what is the histology of the distal convoluted tubule?

Answer 37

simple cuboidal epithelium
weakly eosinophilic
low brush border
impermeable to water/urea

Question 38

what is the histology of the collecting tubules/ducts?

Answer 38

simple cuboidal epithelium
pale cytoplasm
prominent lateral cell boundaries