Kidney, ureter and urinary bladder

Question 1

74. Kidney (HE)

Answer 1

• 10-18 renal lobes
• capsule: fibrous (under which stellate veins
• outer cortex + inner medullary pyramid
• columns of Bertini: cortical extensions between medullary pyramids
• medullary rays
• convoluted part of cortical lobule: between interlobular artery and medullary rays
• nephrons

Question 2

Medullary ray

Answer 2

• radiate towards medulla
• consists of descending/ascending limbs or collecting ducts
• in center of cortical lobules
• bordered by cortical interlobular arteries

Question 3

Renal corpuscle

Answer 3

• initial dilated parts of tubule- confined to renal cortex and columns of Bertini
• consists of central glomerulus + Bowman’s capsule
• Urinary space: between inner and outer endothelial layer of Bowman’s
• Parietal wall of Bowman’s: squamous epithelial cells
• Visceral layer of Bowman’s: podocytes
• efferent and afferent arterioles
• Mesangial cells between arterioles secrete extracellular mesangial matrix
• Juxtaglomerular cells: in afferent arterior, secrete renin
• vascular and urinary pole

Question 4

Proximal covoluted tubule

Answer 4

• simple, tall cuboidal epithelium
• prominent apical brush border- long microvilli
• lumen is ill-defined
• cell boundaries are indistinct
• cells are strongly eosinophilic
• striations in basal cytoplasm of cells ⇒ correspond to elongated mitochondria in basal processes of cytoplasm

Question 5

Loop of Henle

Answer 5

• thick descending limb ⇒ thin descending limb ⇒ thin ascending limb
• simple squamous or very low cuboidal epithelium
• their nuclei are somewhat flattened
• no brushborder in thin limb
• thin⇒ thick ascending limb: basal striation appear

Question 6

Distal convoluted tubule

Answer 6

• epithelium: cuboidal cells
• devoid of brush border
• clearly outlined lumina
• cells paler eosinophilic stain- less organelles
• Macula densa: basophilic, distal tubule close to afferent arteriole
• Juxtaglomerular apparatus: renin secreting cells + macula densa

Question 7

Collecting tubule and duct

Answer 7

• distal convoluted tubule ⇒ straight collecting tubule in medullary rays
• collecting ducts join ⇒ papillary ducts and open at renal papillae
• epithelium: cuboidal- columnar
• ducts of Bellini: largest collecting duct
• pale staining and distinct cell boundary

Question 8

Minor calyx

Answer 8

• ducts of Bellini open into minor calyx
• area cribrosa: area on papilla with openings
• epithelium of papilla: columnar/cuboidal
• epithelium of minor calyx: transitional epithelium
• minor calyx⇒major calyx⇒ renal pelvis

Question 9

75. Kidney (tri-PAS stain)

Answer 9

• stains carbohydrates⇒ brush border of proximal convoluted tubule
• carbohydrate components of glycocalyx show pinkish staining
• arteriolae recta
• venulae recta

Question 10

77. Ureter (HE)

Answer 10

• EPITHELIUM: transitional
• LAMINA PROPRIA: thin dense CT
• MUSCULARIS EXTERNA: inner longitudinal, outer circular
• ADVENTITIA/SEROSA: loose CT, blood and lymph vessels, nerve supply

Question 11

8. Urinary bladder (HE)

Answer 11

• EPITHELIUM: transitional
• LAMINA PROPRIA: no CT papillae, dense fibro-elastic CT, lymphocytes
• MUSCULARIS MUCOSA: rudimentary smooth muscle bundles
• SUBMUCOSA: rich in cells, loose CT
• MUSCULARIS EXTERNA: inner longitudinal, middle circular, outer longitudinal
• ADVENTITIA/SEROSA