1. Histology of the kidney
Ákos Lukást MD., Ph.D

2. Renal lobes (10-18) Medulla: pyramid (papilla), medullary rays
Cortex: cortical labyrinths, columns of Bertini (renal columns)

3. Functional unit: nephron
Cca per kidney

4. Parts of the nephron:
Renal corpuscules (filtration):
-Bowman’s capsules
-Glomeruli
2. Tubules renales (modification):
-Proximal convoluted and straight tubules
-Loop of Henle
-Distal convoluted and straight tubule
Collecting duct

5. Histological vs. Physiological descriptions
Alternative names
-Proximal convoluted - proximal tubule
- Proximal straight – thick descending limb of loop of Henle
-Loop of Henle – thin ascending and descending limb
-Distal straight – thick ascending limb of loop of Henle
Distal convoluted – distal tubule
Histological vs. Physiological descriptions

6. - Subcapsular
- Cortical
- Juxtamedullary
Medullary rays

7. cortex medulla lobule Medullary rays:
Proximal and distal straight tubules, Collecting ducts
cortex
Cortical labyrinths:
Renal corpuscules,
Proximal and distal convoluted tubules
medulla

8. cortex medulla lobule Arcuate artery and vein
Interlobular artery and vein

10. 1. Arteria interlobularis
2. Arteriola afferens
3. Glomerulus
4. Arteriola efferens

11. Peritubular capillaries
Vasa recta
(countercurrent exchange – to maintain the osmotic gradient)

12. Vasa recta

13. Bowman’s capsule:
Parietal layer: simple squamous epithelum
Visceral layer: podocytes
Glomerulus: capillaries
Vascular pole:
- Vas afferens (inflow)
- Vas efferens (outflow)
Urinary pole
Cca. 180 liters of filtrate produced each day
99% is reabsorbed!

14. Podocytes Primary (P1) and secondary (P2) interdigitating processes
Endothelial cells also fenestrated – true filtration barrier is the basal membrane

15. Pressure gradient due to the smaller diameter of the efferent arteriole (filtration pressure)
Generally: Small molecules whose diameter is
smaller than (max ) Daltons
(E.g. water, sugar, ions, amino acids, ammonia, urea, etc)
filtrated into Bowman’s capsule.
Filtration is also dependent on charge (basal membrane has a – charge!)

16. 350 nm töltés barrier fizikalis filter töltés-barrier podokalixin
lamina densa
lamina rara
350 nm
töltés barrier
fizikalis filter
töltés-barrier
podokalixin

17. The juxtaglomerular apparatus
1. Macula densa (Distal convoluted tubule, modified epithelium to detect sodium levels in DCT - chemoreceptor)
2. juxtaglomerular cells in afferent arteriole (renin secretion)
Extraglomerular mesangial cells
Function: tubuloglomerular feedback
regulation of perfusion of the kidneys
regulation of blood pressure

19. JUXTAGLOMERULAR APPARATUS
ACE inhibitors!

20. Proximal and distal tubules

21. Proximal and distal tubules EMI

22. Cortex Outer medulla

23. P P D P D P

24. Loop of Henle, collecting ducts

25. LH D CD LH D CD

26. dp CM
area cribrosa

27. Outer medulla:
Proximal str.
Distal str.
Collecting duct
capillaries
Middle medulla:
Distal str.
Collecting duct
Loop of Henle
capillaries
Inner medulla:
Collecting duct
Loop of Henle
capillaries