pathology of the urinary system lecture-2. recap.. anatomy and physiology of kidney structure of...
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Pathology
of the
Urinary System
Lecture-2
Recap..
Anatomy and physiology of kidney
Structure of nephron and components
Functional aspects
Clinical aspects
Pathogenesis
Recap..
Glomerular basement membrane:
• 320 nm thick in adults
• Central lamina densa
• Lamina rara on either side.
• Contains in addition to IV collagen and other
components, polyanionic proteoglycans.
• Plays a very important role in charge
dependant filtration. Does not allow anions
(proteins) but allows water and cations
Recap..
Filtration barrier of glomerulus:• Fenestrated endothelial cells (70-100 nm)• Glomerular basement membrane• Filtration slits of podocyte (20-30 nm)
Size dependant and charge dependant filtration.Allows particles below 3.5 nm to pass. Restricts albumin (3.6 nm) and other proteins.
Recap..
Juxta-glomerular apparatus:
• JG cells of afferent arteriole
• Macula densa of DCT
• Lacis cells of mesangium
Important source of renin
Plays a role in hypertension
Clinical syndromes related to renal disease
Chr renal failure
Ac renal failure
Nephrotic synd
Acute nephritis
Clinical syndromes related to renal disease
Chr renal failure
Ac renal failure
Nephrotic synd
Acute nephritis
Clinical syndromes related to renal disease
Hematuria, proteinuria, hypertension
Chr renal failure
Ac renal failure
Nephrotic synd
Acute nephritis
Clinical syndromes related to renal disease
Hematuria, proteinuria, hypertension
Proteinuria > 3.5 g/day, hypoalbuminemia <2 g/dl, edema, hyperlipidemia, lipiduria
UremiaChr renal failure
Oliguria / anuria, azotemia, (Anuria <100 ml; oliguria 100-400 ml)
Ac renal failure
Proteinuria > 3.5 g/day, hypoalbuminemia <2 g/dl, edema, hyperlipidemia, lipiduria
Nephrotic synd
Hematuria, proteinuria, hypertensionAcute nephritis
Clinical syndromes related to renal disease
Pathogenesis of Glomerulonephritis
Pathogenesis of glomerulonephritis
Immune mechanisms underlie majority of the primary glomerulonephritis1. In situ immune complex deposition
a. Intrinsic (fixed) glomerular antigensAnti GBM, Heymann nephritis, membranous nephropathyb. Planted antigens (proteins, bacterial, viral)
2. Circulating immune complexes
Others: cytotoxic antibodies, chemical mediators, cell mediated injury, non-immune mechanisms.
Glomerular response to injury
• Glomerulus responds to a variety of injuries in a very limited
manner
• Hypercellularity - mesangial, endocapillary, extracapillary
(crescents), exudation
• Basement membrane changes
• Sclerosis
• Others - Necrosis, deposits of fibrin, abnormal proteins, etc.
Diffuse: All glomeruli in the biopsy / kidney are
affected
Focal: Only few glomeruli are affected (<50%)
Global: The entire glomerulus is involved
Segmental: Only part of the glomerulus (few tufts) are
involved
Terminology
Diffuse changes
Focal changes
Global changes
Segmental changes
Less than 80% of glomerular surface is involved
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