Met histology Flashcards
Portal tract contents
Islands of connective tissue
Contain branches of the hepatic portal vein and hepatic artery
Also contain a bile duct
Bile duct epithelium type
Simple cuboidal
Hepatic lobule
Hexagonal shaped
Central vein (hepatic venue) in the muddle
Portal tracts at corners
Blood flows from corner –> centre
Types of hepatic necrosis
Zonal = in one zone of the acinar unit --> haemodynamic changes Bridging = forms bridge between portal tract and central vein --> severe hepatitis Interface = around a portal tract --> autoimmune Apoptotic = single cells --> acute viral hepatitis
Primary biliary cirrhosis
Autoimmune disease (anti-mitochondrial antibodies) Infiltration of portal tracts Interface necrosis Granulomas around portal tracts --> cirrhosis
Collagen produced in cirrhosis
Types I and III
Classification of nodules
Micro = <3mm --> alcoholic liver disease Macro = >3mm --> greater risk of HCC
HCC features
Cells resemble hepatocytes resting in nests
Central lumen
Bile may be secreted
Pituitary cell types
Somatotrophs (50%) --> GH Mammotrophs (20%) --> PRL Corticotrophs (20%) --> ACTH Thyrotrophs (5%) --> TSH Gonadotrophs (5%) --> FSH and LH
Pituitary stalk contents
Pituicytes
Portal vessels
Hypothalamic neurone axons
Thyroid follicle structure
Lined by simple cuboidal follicular cells –> release T3 and T4
Thyroid colloid in the middle containing thyroglobulin
C cells
= parafollicular cells
Secrete calcitonin in response to high calcium levels
Parathyroid cells
Chief cells --> PTH production Oxyphil cells (small central nuclei) --> function unknown
ZG cells
Rounded clumps
- -> mineralocorticoids
- -> aldosterone
ZF cells
Parallel cords of cells
- -> glucocorticoids
- -> cortisol
ZR cells
Irregular cords of cells
- -> androgens
- -> testosterone
Adrenal gland blood supply
Adrenal artery in capsule Subscapular plexus in ZG Venous sinusoids through ZF Medullary plexus in ZR and medulla Adrenal vein drains from medulla
Medulla blood supply
Blood from the cortex
Direct supply from vessels in the outer cortex
Islet cell proportions
Alpha = 20% Beta = 70% Delta = 5-10% F = 1-2%
Somatostatin release and function
From islet delta cells
Inhibits insulin and glucagon secretion
Pancreatic polypeptide release and function
From F (pp) islet cells Inhibits pancreatic enzyme secretion
Pituitary adenoma cell features
Uniform cells with large amounts of cytoplasm
Reduction in supporting network
Large areas stain positive for the same hormone
Features of Grave’s disease
Thyrotoxic hyperplasia
Colloid scallopping
Follicular cells are taller with larger nuclei
Follicles themselves are smaller
Renal cortex contents
Renal corpuscles PCT DCT Capillary network Medullary rays (some collecting ducts)
Renal medulla contents
Loops of Henle
Collecting ducts and tubules
Vasa recta
Bowman’s capsule walls
Visceral = podocytes Parietal = simple squamous
Glomerular filtration barrier
Podocytes
Basement membrane
Glomerulus endothelium
PCT wall structure
Simple cuboidal
Brush border
Endocytotic vesicles + lysosomes
Basolateral interdigitations
Loop of Henle sections
Pars recta = same structure as PCT
Thin descending limb = simple squamous
Thin ascending limb = simple squamous
Thick ascending = simple cuboidal with basal interdigitations
Loop of Henle permeability
Thin descending = permeable to urea and water but not NaCl
Thin ascending = permeable to NaCl but not water
Thick ascending = active transport of NaCl
DCT wall structure
Simple cuboidal
Few microvilli and vesicles
No brush border
Basolateral interdigitations
Collecting duct wall structure
Simple cuboidal
No interdigitations
Juxtaglomerular cells
Specialised smooth muscle cells
Around afferent (few in efferent) arterioles
Secrete renin
Beta1 receptors for SNS stimulation
Macula densa cells
Taller and more densely packed than the rest of the DCT
Sense the sodium concentration
Communicate with JG cells via mesangial cells
Lacis cells
Extraglomerular mesangial cells
Urinary passageway mucosa
Transitional epithelium
Impermeable to urine
Ureter muscle layers
Inner = longitudinal Middle = circular Outer = longitudinal
Urinary passageway layers
Transitional epithelium
Lamina propria/submucosa (no musculares mucosae)
Muscularis (3 layers)
Adventitia
Glomerular response in GN
Swelling of endothelial cells
Podocyte proliferation
BM thickening
Mesangial cell proliferation
Histological patterns of GN
Diffuse = affects all glomeruli Focal = affect some glomeruli Global = entire glomerulus abnormal Segmental = only part of the glomerulus abnormal
Minimal change GN
–> nephrotic syndrome
Cell mediated immune response
LM is normal
EM shows flattened podocyte foot processes
Children under 6 after respiratory infection
Corticosteroid treatment
Membranous GN
–> nephrotic syndrome
Chronic immune mediated disease
LM shows diffuse BM thickening
EM shows deposition of electron dense immune complexes
Occurs in adults
Associated with infection, drugs, tumours and autoimmune disease
Diabetic GN
–> nephrotic syndrome
Caused by hyperglycaemia
Capillary wall thickening, mesangial matrix expansion, BM thickening
Kimmelstein-Wilson nodules (mesangial expansion)
Acute proliferative GN
–> nephritic syndrome
Diffuse glomerular hypercellularity
–> proliferation of endothelial and mesangial cells
–> neutrophil infiltration
Occurs most commonly in children 1-4 weeks after Strep infection of pharynx or skin
EM shows sub endothelial lumps (immune complex deposition)
Nephrotic vs nephritis syndrome
Nephrotic = without inflammation
Nephrotic –> proteinuria, hypoalbuminaemia, oedema, hyperlipidaemia, lipiduria
Nephritic –> haematuria, proteinuria, periorbital oedema, hypertension
Renal cell carcinoma
Adenocarcinomas derived from tubular epithelial cells
90% of primary kidney tumours
Clear cell carcinoma
Derived from PCT cells
Tend to invade renal vein
Transitional cell carinoma
Most common malignant bladder tumour
Often have a papillary growth pattern
May see large blood vessels
Nephroblastoma
= small round blue cell tumour
= Wilm’s tumour
Very rate
Seen in very young children
