Histology - Renal

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kidney (outer portion)

*outer portion (capsule) covered by dense irregular FECT
*outside of capsule
*cortex <- presence of renal corpuscles (circular structures)
*renal corpuscles = renual tubule (bowman's capsule) + capillary plexus (glomerulus)

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lobe of kidney (deeper portion) where cortex meets medulla

*cortex <- presence of medullary rays (where kidney tubles line up in parallel)
*medulla <- no renal corpuscles

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cortico-medullary junction

*alternating medullary rays and cortical labyrinth
*medulla <- no renal corpuscles

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inner medulla

*cup-shaped <- minor calyx (renal papilla)
*inner medulla <- considerable extracellular matrix in between individual kidney tubules, proximity to minor calyx

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renal corpuscle = juxtaposition of capillaries (glomerulus) + cells comprising Bowman's capsule

* Bowman's capsule <- periphery of renal corpuscle
* podocytes <- large, euchromatic nuclei, (compare to endothealial cells)

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cortical labyrinth within cortex of kidney.

* glomerular arterioles <- 1 smooth muscle cell layer within tunica media
* proximal tubules <- cells in pyramidal in shape, cytoplasm stains deeper red and is somewhat granular, indistinct luminal border (due to microvilli collectively called brush border)
* distal tubule <- cells are more cuboidal, stain less intensely, luminal border is smoother
*

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real corpuscle in renal cortex

*proximal tubules <- nondistinct lumen due to brush border
*distal tubule <-distinct lumen

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cells comprising filtration barrier within renal corpuscle

* wide loops representing a portion of glomerulus lined by indothealial cells
* glomerular basement membrane <- wall of the capillary that appears relatively thick
* podocytes <- larger, more euchromatic nuclei (form the viceral layer of Bowman's capsule

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region surrounding renal corpuscles within kidney cortex

* proximal tubule cells <- larger and more pyramidal in shape so fewer nuclei are seen per given area, more intensly stained cytoplasm more irregular luminal border compared to distal tubule cells
* brush border <- microvilli which forms irregular cellular border of proximal tubules

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medullary ray within renal cortex

*thick decending limbs (first part of loop of Henle <- resemble proximal tubule cells in morphology
*thick ascending limbs of loopf of Henle <- cells which are low cuboidal, nuclei often bulge into the lumen
*collecting ducts <- simple cuboidal epithelium centrally placed nuclei

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medullary ray at higher magnification

* intercellular junctions between collecting duct cells are apparent
*

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outer mudulla of kidney

*cells that comprise collecting cuts are taller -> simple columnar not simple cuboidal epithelium
*thick ascending and thick decending limbs are not distinguishable (just called thick limbs)
* vasa recta (capillary network blood supply of the medulla) <- vessels with large luminal size with extremly thin endothelium
* thin limbs of loop of Henle <- lined by simple squamous epithelium but are thicker than endothealial cells and nuclei tend to bulge into lumen

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outer medulla of kidney

*much less extracellular space
*large number of thick limbs and relatively few thin limbs
*collecting duts have cells which are less tall than thoes of the inner medulla

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inner medulla merging with minor calyx (called the renal papilla)

*contains collecting ducts, thin limbs, loope of Henle and vasa recta
*greater amounts of extracellular matrix
*collecting ducts <-very tall simple columnar or stratified which drain into minor calyx

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inner medulla at higher mag

*collecting duct lined by very tall simple columnar epithelium
*vasa recta <-very thin walls
* thin limbs of the loop of Henle (thicker cells with nuclei that often bulge into the lumen)

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* cortical labyrinth of renal cortex in a juxtaglomerular appratus

*each distal tubule of each nephron passes next to its own renal corpuscle
*macula densa <-distal tubule cells become larger and more stratified
*juxtaglomerular appratus <- cells of afferent arteriole (JG cells) and the extraglomerular mesangium

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inner medulla (innermost portion)

*lies next to minor calyx (called renal papilla)

*many collecting ducts converge to train into the minor calyx
*minor calyx receives all the urine production from one lobe of the kidney

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minor calyx

* lined by transitional epithelium
* receives all urine produced by one lobe of the kidney and drains to a major calyx which drains to renal pelvis and then ureter
*has an incomplete layer of smoother muscle

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subjacent region to the minor calyx (renal sinus)

*filled with adipose and loose connective tissue
*region where larger renal blood vessels branch

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renal sinus

*located between two lobes
*branhes of the renal arterial system arise (called interlobar arteries) which run between two adjacent lobes and branche arcuate arteries which enter each lobe at the cortico medullary junction

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cortico-medullary junction

*arcuate vessesl found here
*acurate artery->branch to interlobular arteries which run out into the cortex
*venus blood from interlobular veins drain into the arcuate veins along with the vasa recta returning venus blood from he medulla

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midle of cortical labyrinth

*large arterioles found called interlobular arteries
* send off many branches to either side each called afferent glomerular arteriole which supplies each glomerulus
*kidney lobule <- region of cortex with medullar ray and cortical labyrinth on either side
* the middle of the cortical labyrinth represent the edge of a kidney lobule
* venou s blood from these reions drains o interlobular veins which in turn drain to arcuate veins

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cortical labryinth

*spaces between renal tubules is not empty but is occupied by an elaborate capillary complex called peritubular capillaries which receive solutes and water that are reabsorbed by the nephron (drain to interlobular vieins

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ureter in transverse section

*lamina propria (dense irregular FECT)
*layer of smooth muscle (tunica muscularis)
*outer layer of connective tissue (tunica adventitia
*star shaped appearance (because of contraction of smooth muscle)

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ureter at higher mag

*smoother muscle of tunica muscularis organized into bundles
* tunica muscularis surrounded by dense irregular FECT
* inner ortion of smooth muscle arranged parallel to the long axis of the ureter (inner longitudinal)
* outer portion of smooth muscle arranged concentrically about the lumen (outer circular)

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ureter at higher mag

*epithelial lining cinsisting of translational epithelium
* region of dense irregular FECT between epithelium and smoother muscle (lamina propria)
* no submucosa within ureter

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bladder at low mag

*like ureter, ladder is lined by transitional epithelium, has lamina propria consisting of dense irregular FECT, a tunica muscularis with inner logitudinal an douter circular smooth muscle and outer adventitia
* unliek ureter, bladder is larger organ so cant see entire lumen and contains a submucosa which consists of dense irregular FECT

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bladder at high mag

*epithelial lining of bladder is transitional epithelium
*densely packed lamina propria and more loosely arranged submucosa

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bladder smoother muscle

*like the ureter, the smoother muscle of the tunica muscularis of the bladder consists of smooth muscle arranged in bundles surrounded by connective tissue
* inner layer of smoother muscle is oriented parallel to the long axis of the bladder (inner longitudinal smoother muscle)
* outer layer is arranged concentrically about the lumen (outer circular smoother muscle