The document provides a detailed overview of kidney histology, including the general organization of renal structures such as the capsule, cortex, and medulla. It discusses the components of nephron anatomy, highlighting the roles of renal tubules and specific cell types involved in renal function. Key cellular features, including myofibroblasts and specialized structures like the juxtaglomerular complex, are described in relation to their physiological significance.

1. HISTOLOGY OF KIDNEY
Dr. Syeda Iqra Mushir
PGY-1
Histopathology
PIMS

2. GENERAL ORGANIZATION
OF RENAL STRUCTURE
• CAPSULE
• CORTEX
• COTICAL LABYRINTH
• MEDULLARY RAYS
• MEDULLA
• RENAL PYRAMIDS
• CORTICAL/RENAL COLUMNS
• RENAL PELVIS
• MAJOR AND MINOR CALYXES

3. INTERNAL
GROSS
ANATOMY
OF
KIDNEYS

4. LOBES AND LOBULES
• Each kidney lobe consists of
• Medullary pyramid
• Cortex
• Renal lobule
• Portion of kidney containing those
nephrons that are served by a common
collecting duct
Lobule
lobe

5. HISTOLOGY
• Renal capsule
• Outer mainly consists of collagen fibers
• Inner mainly has myofibroblast
• Myofibroblasts
• contractile, α-smooth muscle actin-
positive cells
• multiple roles in pathophysiological processes.
Like
• wound contractions, their persistent presence
in tissues is central to driving fibrosis, making
them attractive cell targets for the
development of therapeutic treatments.

7. URINIFEROUS TUBULE
• Nephron
• Collecting tubule

8. PARTS OF NEPHRON

9. CORTICAL LABYRINTH
• Renal corpuscle
• Convoluted tubule

10. BOWMANS CAPSULE

11. GLOMERULUS

12. RENAL CORPUSCLE

16. MESANGIAL CELLS
• Found within the glomerulus
• These cells secrete a matrix of
basement membrane–like material to
support the structure of the
glomerulus.

17. PROXIMAL CONVOLUTED TUBULE
• Longest and tortuous part of the
nephron
• Commences at urinary pole
• Occupies a major part of the cortex
• Lined by low columnar epithelium
• Show brush border
• Absorb sodium

18. LOOP OF HENLE
• The thin segment of Henle's loop leads into
the straight part of the distal tubule which is
formed by low cuboidal cells without a brush
border. A few short microvilli are present
• Epithelial cells in the ascending parts of the
intermediate and straight distal tubule cells
transport chloride ( active) and sodium ions (
passive) out of the tubular lumen into the
surrounding peritubular space.
• The epithelium can not be penetrated by
water. Consequently, the transport of ions
over the epithelium sets up a gradient in
osmotic pressure, which serves as a driving
force in the further concentration of the urine.

19. DISTAL CONVOLUTED TUBULE
• Slightly tortuous
• Lined by simple cuboidal epithelium
• Absorption of sodium and chloride

22. COLLECTING DUCT
• Excretory ducts
• Present in medullary rays
• Lined by simple cuboidal epithelium
• Transport urine from the nephron to
the renal pelvis

23. MEDULLARY RAYS
• Formed of straight tubules and
collecting duct
Medullary rays are cellular structures found in
some species of wood. They appear as radial
planar structures, perpendicular to the growth rings,
which are visible to the naked eye

24. JUXTA GLOMERULAR COMPLEX

25. MACULA DENSA
• Specialized region of DCT
• Cells are tall columnar
• Closely packed nuclei
• Thin and discontinuous basal lamina
• Release renin

26. JUXTA GLOMERULAR CELLS
• Present adjacent to macula densa .
• Epithelioid cells in tunica media
• Large
• Internal elastic lamina is absent

27. EXTRA GLOMERULAR MESANGIAL
CELLS
• Form a cushion of cells between
afferent and efferent arteriole
• Structurally resemble intraglomerular
cells
• Functional significance not clear

28. THANK YOU