Histology of Glomerulus

Basics of Anatomy and Histology of Kidney of Human Body

1. Histology of Glomerulus Presented By :- Shubham Gupta 1 st MBBS Dept. of Anatomy

2. INTRODUCTION Excretory System consists of : A pair of Kidney A pair of Ureter Urinary Bladder Urethra Functions : Production Transport Storage Excretion

3. Introduction Nephron :- Structural and Functional Unit of Kidney. Parts of nephron :- 1. Malphigian Body or Corpuscles or Renal Corpuscles :- a . Glomerulus b. Bowman’s Capsule 2. Renal Tubules- a. Proximal Convoluted Tubule b. Loop Of Henle : Ascending limb : Descending limb c. Distal Convoluted Tubule d. Collecting Duct

4. Glomerulus Network or Tuft of anastomosing capillaries that perform the 1st step of filtering the blood. Present in Cortex part of Kidney. Surrounded by double layered Bowman's capsule :- Inner or Visceral Layer :- -Consists of :- Podocytes - Pedicles - Filtration slits ii. Outer or Parietal Layer :- -Lining Epithelium :- Simple Squamous Epithelium . According to Gray's - Glomerulus is distribution of blood vessels in the cortex of kidney.

5. Glomerular Filtration Barrier Formed by :- Capillary endothelium Podocyte cells - forming visceral layer of glomerular capsule. Glomerular basement membrane - represents the fused basal lamina of above both lamina.

6. Glomerular Filtration Barrier Formed by :- Capillary endothelium Podocyte cells - forming visceral layer of glomerular capsule. Glomerular basement membrane - represents the fused basal lamina of above both lamina.

7. 1. Endothelial cells : Show numerous fenestrae or pores through which filtrate can easily pass.

8. 2. Podocytes (foot like processes) :- - Primary processes : # Show star shaped appearance # Wrapped around glomerular capillaries.

9. - Secondary processes(Pedicels or end feet) : # Each primary process terminates in numerous Pedicels that rest on basal lamina.

10. - Filtration slits or Slit pores : # Gaps b/w attachments of individual pedicels through which filtration takes place.

11. Glomerular Basement Membrane Formed by fusion of endothelium and podocytes . Thickness - about 300 nm. Forms both physical as well as electrical barrier to passage of large molecules [i.e.- proteins(albumin)]. Made up of 3 layers :- a. Lamina densa : Act as a physical barrier since it contains a network of collagen fibrils. b. Lamina rara interna : separates endothelial cytoplasm from mesangium . c. Lamina externa .

12. Mesangium Forms mesentry like fold over the capillary loop. Contains :- a. Mesangial matrix b. Mesangial cells ( Lacis cells) :- - Contains filaments similar to myosin. - Bear Angiotensin II receptors. - Stimulation of these receptor by angiotensin causes fibrils to contract.

13. Functions :- Supporting glomerular capillaries. Phagocytosis Maintainence of glomerular basement membrane.

14. Applied Nephrotic Syndrome :- Proteinuria Hypoalbuminemia Lipidiuria Hyperlipidemia Cause :- Loss of high negative charges in basement membrane and in podocyte processes. Glomerulonephritis :- - Due to impaired function of Mesangium , it lead to Inflammation of Glomerulus.

15. APPLIED Importance of Histopathology- Kidney biopsy. To detect renal pathology. During kidney transplantation.

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