renal histology laith srour - medicinebau.com · remember that the renal corpuscle both indicates...
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RENAL HISTOLOGY
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laith srour
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REnal capsule
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medulla
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cortex
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hilum
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ureter
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papila
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cortex
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outer medulla
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inner medulla
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Renal capsule
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Remember that the renal corpuscle both indicates the cortex as well as the cortical labyrinth (E) within the cortex. In addition, the cortical labyrinth contains both the proximal and distal convoluted tubules. The medullary rays (F), which appear as rays radiating from the medulla, contain the thick ascending and descending segments of the renal loop and collecting tubules
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cortical labrynth
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medullary rays
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renal corpuscle
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urinary space
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Thick descending
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Thick ascending
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Thick descending
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thick ascending
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Thin
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thin
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collecting tubule
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Papillary duct
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ureter
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Renal pelvis
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lined bu transitional wpithelium\Urothelium
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A coronal view (left) shows the major blood vessels . An expanded diagram (right) includes the microvascular components extending into the cortex, and medulla from the interlobular vessels are shown on the right. Pink boxes indicate vessels with arterial blood and light blue indicate the venous return. The intervening lavender boxes and vessels are intermediate sites where most reabsorbed material reenters the blood.
Renal Corpuscle
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At the beginning of each nephron is a renal corpuscle, about 200 μm in diameter and containing a tuft of glomerular capillaries, surrounded by a double-walled epithelial capsule called
Lining of BC
Parietal – Simple
squamous Visceral-
Podocytes
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(a) The renal corpuscle is a small mass of capillaries called the glomerulus housed within a bulbous glomerular capsule. The internal lining of the capsule is composed of complex epithelial cells called podocytes, which cover each capillary, forming slit-like spaces between interdigitating processes called pedicels. Blood enters and leaves the glomerulus through the afferent and efferent arterioles, respectively. (c) Filtrate is produced in the corpuscle when blood plasma is forced under pressure through the capillary fenestrations, across the filtration membrane or GBM surrounding the capillary, and through the filtration slit diaphragms located between the podocyte pedicels. (d) The scanning electron microscopy (SEM) shows the distinctive appearance of podocytes and their pedicel processes that cover glomerular capillaries. X800
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b) The micrograph shows the major histologic features of a renal corpuscle. The glomerulus (G) of capillaries is surrounded by the capsular space (CS) covered by the simple squamous parietal layer (PL) of Bowman capsule. Near the corpuscle is that nephron’s macula densa (MD) and sections of proximal convoluted tubules (PCT) and distal convoluted tubules (DCT). H&E. X300.
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imp.
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Simple squamous parietal layer
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Proximal convolted tubule ,Look how its thicker than DCT
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Macula densa near Distal convoluted tubule (DCT)\\ The cells not the tube-like thing
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podocyte cell body
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Basement membrane of capillary
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endothelium
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pedicles
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The glomerular filtration barrier consists of three layered components: the fenestrated capillary endothelium, the glomerular basement membrane (GBM), and filtration slit diaphragms between pedicels. The major component of the filter is formed by fusion of the basal laminae of a podocyte and a capillary endothelial cell. (a) TEM shows cell bodies of two podocytes (PC) and the series of pedicels on the capillary (C) basement membrane separated by the filtration slit diaphragms. Around the capillaries and podocytes is the capsular space (CS) into which the filtrate enters. The enclosed area is shown in part b. X10,000. (b) At higher magnification, both the fenestrations (F) in the endothelium (E) of the capillary (C) and the filtration slits (FS) separating the pedicels (P) are clearly seen on the two sides of the thick, fused basement membrane (BM). Thin slit diaphragms (SD) bridge the slits between pedicels. X45,750.
Mesangial Cells
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Simple squamous
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Proximal Convoluted Tubule
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covered with simple cuboidal
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(a) The micrograph shows the continuity at a renal corpuscle’s tubular pole (TP) between the simple cuboidal epithelium of a proximal convoluted tubule (P) and the simple squamous epithelium of the capsule’s parietal layer. The urinary space (U) between the parietal layer and the glomerulus (G) drains into the lumen of the proximal tubule. The lumens of the proximal tubules appear filled, because of the long microvilli of the brush border and aggregates of small plasma proteins bound to this structure. By contrast, the lumens of distal convoluted tubules (D) appear empty, lacking a brush border and protein. (b) Here the abundant peritubular capillaries and draining venules (arrows) that surround the proximal (P) and distal (D) convoluted tubules are clearly seen. Both X400. H&E.
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So look for torturus simple cuboidal cells making a tube\\ Also it contains some stuff unlike distal which is clear\\ and they are abundant
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This is still parietal layer so it is simple squamous
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this is proximal tubule with simple cuboidal
Loop of Henle
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(d) A cross section through a medullary pyramid shows the simple squamous epithelium of the thin descending and ascending limbs of loops of Henle (T) and its thick ascending limbs (A), as well as the pale columnar cells of collecting ducts (CD). Note also the homogeneous interstitium with capillaries smaller than the thin limbs. X160. Mallory trichrome.
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thick ascending limb\\simple cuboidal
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Thin ascending & descending\\simple squamous
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collecting ducts\\columnar
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capillaries smaller than Thin limb\\one nucleus(be carefull because in thin limb nucleus is not always seen good
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cd
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a
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t
DCT
Distal Convoluted Tubule
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PCT
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Peritubular capillaries and drainage venules filed with blood
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DCT
Juxtaglomerular Apparatus
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The JGA forms at the point of contact between a nephron’s distal tubule (D) and the vascular pole of its glomerulus (G). At that point cells of the distal tubule become columnar as a thickened region called the macula densa (MD). Smooth muscle cells of the afferent arteriole’s (AA) tunica media are converted from a contractile to a secretory morphology as juxtaglomerular granule cells (JG). Also present are lacis cells (L), which are extraglomerular mesangial cells adjacent to the macula densa, the afferent arteriole, and the efferent arteriole (EA). In this specimen the lumens of proximal tubules (P) appear filled and the urinary space (US) is somewhat swollen.
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Macula densa\\columnar
Collecting Tubule
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Vasa recta
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Pale-staining columnar principal cells, in which ADH-regulated aquaporins of the cell membrane allow more water reabsorption, are clearly seen in these transversely sectioned collecting ducts (CD), surrounded by interstitium with vasa recta (VR)
Ureter
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(a) Diagram of a ureter in cross section shows a characteristic pattern of longitudinally folded mucosa, surrounded by a thick muscularis that moves urine by regular waves of peristalsis. The lamina propria is lined by a unique stratified epithelium called transitional epithelium or urothelium that is resistant to the potentially deleterious effects of contact with hypertonic urine. (b) Histologically the muscularis (Mu) is much thicker than the mucosa (M) and adventitia (A). X18. H&E.
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Mucosa lined with urothellium
Ureter
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mucosa
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muscularis
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adventetia
Urinary
Bladder
Empty Full
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**When the bladder is empty, the mucosa is highly folded and the urothelium (U) has bulbous umbrella cells. ** When the bladder is full, the mucosa is pulled smooth, the urothelium (U) is thinner, and the umbrella cells are flatter.
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prostatic urethra Lined by urothelium
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or spongy\\The spongy urethra, about 15 cm in length, is enclosed within erectile tissue of the penis (see Chapter 21) and is lined by stratified columnar and pseudostratified columnar epithelium (Figure 19–18), with stratified squamous epithelium distally
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Urethra
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The urethra is a fibromuscular tube that carries urine from the bladder to the exterior of the body. (a) A transverse section shows that the mucosa has large longitudinal folds around the lumen (L). X50. H&E. (b) A higher magnification of the enclosed area shows the unusual stratified columnar nature of the urethral epithelium (E). This thick epithelial lining varies between stratified columnar in some areas and pseudostratified columnar elsewhere, but it becomes stratified squamous at the distal end of the urethra
Thank you