Liver and Kidney Flashcards
(20 cards)
Define the term “liver unit”
Liver unit= functional units of the liver involved int he processes of detoxification, metabolism, bile production and protein synthesis
Highlight the distinctive features of the classical lobule, portal lobule and liver acinus.
Classic lobule- central vewin inthe centre of the liver, with portal traids at the corners
Portal lobule- triangular in shape, aids bile flow from hepatocytes to bile ducts
Liver acinus- 2 central veins at ends, functional blood supply, nutrient and oxygen delivery to hepatocytes
What structures can be found in a Portal triad?
Branches or portal vein
Hepatic artery
Bile ducts
Small lymphatic vessels
Highlight the location of hepatocytes, hepatic sinusoids (and endothelial cells), Space of Disse, Kupffer cells, Hepatic Stellate Cells, Cholangiocytes and bile canaliculi in the liver.
Hepatocytes- liver lobules, maily around sinusoids
Hepatic sinusoids- specialized capillaries between hepatocyte plates
Space of disse- between sinusosids and hepatocytes
Kupffer cells- along sinusoids
Hepatic Stellate cells- space of disse
Cholangiocytes- lining of the bile ducts (in portal triad)
Bile canaliculi- small channels between adjacent hepatocytes
Define the function and histological structure of hepatocytes, hepatic sinusoidal endothelial cells, Kupffer cells, Hepatic Stellate Cells and Cholangiocytes.
Hepatocytes- large polygonal cells with a central nucleus, main liver cells involved in all processes
Hepatic sinusoidal endothelial cells- flattened endotheial cells with large gaps, form lining of sinusoisdal cells, regulate blood flow
Kupffer cells- large irregularly shaped cells, specialised macrophages that phagocytose pathogens
Hepatic stellate cells- star shaped cells, store vitamin A and regulate extracellular matrix
Chalangiocytes- simple cuboidal cels that line the bile duct, modify bile as it flows through the biliary tree
Define the relationship between Hepatic Stellate Cell - Myofibroblast - excessive collagen deposition in liver fibrosis.
Hepatic stellate cells become activated, meaning they become myofibroblasts, producing excessive collagen leading to liver fibrosis
Identify applications of common special stains used to highlight pathology in the liver
H&E- general liver tissue examination
Masson’s Trichrome Stain- highlights collagen and fibrosis in liver tissue
Reticulin (silver) stain- stains reticulin fibres in the liver, used to evaluate fibrosis and cirrhosis
PAS- stains glycogen and glycoproteins in liver tissue
Identify the flow of bile from canaliculi to duodenum
- Bile initially produced by hepatocytes and secreted to bile canaliculi
- Bile flows into the canals of Hering
- From the canals of Hering, bile drains into intraheptic bile ducts (in portal traids)
- These ducts merge into common hepatic duct, ewhich joins the cytic duct from the gallbladder to form the common bile duct
- Common bile duct delivers bile into the duodenum
where can we find the Cholangiocytes and stem cells of the liver?
Cholangiocytes- lining of bile ducts throughout the liver
Stem cells of the liver- oval cells are found in the canals of hering and hepatic progenitor cells are found near the portal tracts
What are fenestrae, where can they be found and what is the purpose?
Small pores/ openings in the cytoplasm of liver sinusoidal endothelial cells
Found in hepatic sinusoids
Allow for free exchange of water and small plasma proteins between blood and sinusoids
What are the hall marks of liver cirrhosis?
Distorted liver architecture
Loss of liver fucntion
Chronic inflammation
Identify the main divisions of the kidney
1- Capsule
2- Cortex
3- Medulla
4- Pelvis (beginning of main excretory duct)
What is the location, function and histological structure of the Glomerulus?
Found in the renal cortex, within the renal corpuscle
Acts as a site of blood filtration
Tuft of fenstrated capillaries, derived from the afferent arteriole and drained by the efferent arteriole
Identify the different sections of the Nephron and the different epithelial cell types found along the tract. What are the distinctive features of these epithelial cells?
Bowman’s Capsule- podocytes have foot processes forming filtration slits
PCT- extensive microvilli inc SA for reabsorption
Loop of Henle- thin descending and thick ascending limb
DCT- clear cytoplasm and prominent nuclei
Collecting duct- clear boundaries between cells and no brush border
What is the location and function of the Macula Densa and Juxtaglomerular cells (Juxtaglomerular Apparatus)?
Macula Densa- located in DCT, senses NaCl concentration in the filtrate flowing through
Juxtaglomerular cells- located in the afferent arteriole, secretes renin in response to signals from the macula densa/ in response to low blood pressure
What are Medullary Rays and where can we find them?
Collections of straigth tubules that extend from the renal medulla into the renal cortex
Found in the renal cortex, between the renal lobules
Where can we find transitional epithelial in the Kidney and why in these locations?
Renal pelvis, ureter, bladder and proximal urethra
Transitional epelium is specialised for areas that need to stretch and distend to accomodate changing volumes of urine
Identify the different sections of the arterial and venous system of the Kidney
Arterial system- Renal Artery → Segmental Arteries → Interlobar Arteries → Arcuate Arteries → Interlobular Arteries → Afferent Arterioles (supply glomeruli)
Venous system- Efferent Arterioles → Peritubular Capillaries/Vasa Recta → Interlobular Veins → Arcuate Veins → Interlobar Veins → Renal Vein → Inferior Vena Cava
Identify applications of common special stains used to highlight pathology in the Kidney.
H&E- to examine histological structure of kidney tissues
PAS- used to assess glomerular diseases
Trichrome stain- stains collagen fibres to evaluate fibrosis
Congo red- detection of amyloid deposits
Where can we find the basement membrane in the Glomerulus and how is it changed in membranous Glomerulonephritis?
Between the endothelial cells and podocytes in the glomerulus, forms part of the filtration barrier
Changes- GBM thickens due to immune complex deposition, leads to spikes/ domes on the membrane impairing filtration
