henle loop fenestrated capillary

8/14/2019 Henle Loop Fenestrated Capillary

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Kidney and Urinary System

CTB Lab 9


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General Kidney Features

(macroscopic structure)


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Kidney

Retroperitoneal

Encapsulated w/ Dense Irregular CT

Cortex

outermost region

Cortex composed of

Renal corpuscles (little circles)

Proximal/Distal Tubules

Capillaries

Medullary rays

Kidney (monkey):

RC renal corpuscles

V interlobular veinCx cortex

MR medullary ray

AV arcuate vein

AA arcuate artery

G glomerulus

IA interlobular artery

RP renal papilla

C calyxP renal pelvis

U ureter

Ai interlobar artery

T tubule

Zoom to ~150% to really see the

arteries and veins


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Renal Corpuscle1. Glomerulus tuft of fenestrated capillaries

2. Mesangial cells modified sm muscle cells, support glomerulus, maybe maintain Glomerular bsmt membrane

3. Bowmans Capsule double walled epithelial layer surrounding glomerulus (Visceral + Parietal)

Question 1: *Parietal Layer of Bowmans Capsule is made up of Simple Squamous Epithelial cells

Visceral layer of Bowmans Capsule consists ofPodocytesQ2: *Nuclei within Glomerulus belong to 3 types of cells: Capillary endothelial cells, Podocytes, Mesangial Cells


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Renal Corpuscle

Schematic


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Renal corpuscle:

A afferent arteriole

C glomerular capillary

E endothelial cell

GBM glomerular basementmembrane

I interstitium

M mesangium

N mesangial cell nucleus

PCT proximal convoluted tubule

S squamous cell

Renal Corpuscle


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Glomerular Filter SchematicGlomerulusBC Bowman's capsuleBM basement membraneBS Bowman's space (urinary space)C capillary loopE endothelial cellF fenestrationsFS filtration slitM mesangial cellMM mesangial matrixP podocyteP1 podocyte primary processP2 podocyte secondary foot process

Q3: **The Clear Space between the Glomerulusand Parietal Layer of Bowmans Capsule is called theUrinary Space (Bowmans Space in Wheatersdiagrams)

**The Urinary Space contains Plasma Ultrafiltrate itpassed from capillaries into it.

Q4: **3 Components of the Filtration barrier going

from glomerular caps to urinary space:1) Fenestrated capillary endothelial cells (ECs)2) Fused basal laminae of cap ECs & podocytes3) Diaphragm-covered filtration slits betweenpodocyte foot processes


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Ultrastructure of Podocytes & Endothelial CellsGlomerulus

BC Bowman's capsule BM basement membrane

BS Bowman's space C capillary loop

E endothelial cell F fenestrationsFS filtration slit M mesangial cell

MM mesangial matrix P podocyte

P1 podocyte primary process

P2 podocyte secondary foot process


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Slide 27 Kidney PAS

Note intense staining within glomerulus

It indicates the Basal Lamina that contributes to the glomerular filtration barrier.


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Back to slide 26

Afferent Arteriolefeeds glomerular caps

Efferent Arterioledrains glomerular caps

Both enter/exit the renal corpuscle at theVascular Pole

Urinary Poleopposite from Vascular pole; where plasma ultrafiltrate drains from corpuscle.Q5: **Plasma Ultrafiltrate drains from urinary space into proximal tubule.


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Nephrons functional units of the kidney,

composed of four things:

Proximal and distal

convoluted tubulesBB brush border

BM basement membraneC peritubular capillaries

DCT distal convoluted tubule

PCT proximal convoluted tubul

1- Renalcorpuscle

2- Proximal tubule

3- Loop of Henle

4- Distal Tubule


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How to Distinguish Renal Tubes

-No brush border-Makes lumen appear wider/open

-Have a brush border (microvilli)-More Prox tubules than Distal;so will see more of these in Xsection

Extra info:

PalePaleEosinophilic & Granular(b/c abundant mitochondria,basal membrane infoldings)

Cytoplasmicstaining

Many centrallylocated

Many centrally located(beccause cells are smaller)

Few basally located(because cells are so large)

Nuclei in agiven plane ofsection

DistinctIndistinct(lateral borders highlyinterdigitate)

Indistinct(lateral borders highlyinterdigitate)

Cell borders

-Open

-Scalloped edge b/ccells bulge inward

-Open

-Wide

-Smooth contour

Occluded

Jagged outline

LumenCharacteristics

Cuboidal ColumnarLow CuboidalIn other words, shorter cellsHigh CuboidalIn other words, Large cells

Type ofEpithelium

Collecting DuctDistal TubuleProximal Tubule

Q6:**Cells in the Proximal Tubule function to resorb lots:

Active Reabsorption = Na/Cl

Passive Reabsorption = water (follows NaCl)

Facilitated Reabsorption = Glucose / AAs / Proteins

Q7: **Distal Tubule Cells only resorbe Na/Cl


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B Bowman's space

CP mesangial cell cytoplasmic processes

MC mesangial cell

MM mesangial matrix

P1 podocyte primary process

P2 podocyte secondary foot process;

BM basement membraneBME basement membrane of endothelium

Cap capillary

E endothelium

J junctional complex

L lysosome

M mitochondrion

Mv microvilli

P cell processes

S supporting tissueV pinocytotic vesicle

E endothelial cell

Structure of the Tubules with

adjacent capillaries for

reabsorption


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More Comparison of Proximal vs Distal Tubules


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MACULA DENSA:Place where the Distal Tubule passes close by the Vascular Pole

The Distal Tubules Columnar Cells are Tightly Packed here

Function: monitors the sodium concentration and volume of ultrafiltrate in the tubule

MACULA DENSA


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MACULA DENSAQ7: ** Macula densa is part of a larger structure called the Juxtaglomerular Apparatus, which

includes specialized cells in a portion of the afferent arteriole.

Q8: ** The secretory product of the juxtaglomerular cells of the afferent arteriole is Renin.

S /C


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See/Compare:

-Glomerulus

-Macula densa

-Proximal tubule

-Distal tubule


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Loop of Henle(Intermediate Tubule)

Collecting tubules and ductsA thick ascending limb of loop of Henle

T thin limb of loop of Henle

CD collecting duct

CT collecting tubule

IC intercalated cell

V vasa recta

A U-shaped tube connecting the

proximal and distal tubules

First section of Henles loop is a thick

descending limb; goes from cortex

medulla via Medullary Rays

Thin loops dip down into the

medulla and go back up to

the cortex.

To identify look for squamous

cells, but they shouldnt have

bright RBCs within those

are capillaries.

Dont forget that Henles Loop functions as a Countercurrent Multiplier.


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Collecting tubules and ductsBM tubular basement membrane

CD collecting duct

IC intercalated cell

S supporting tissue

*The nephron stops at the end of the

distal tubule.. Doesnt include the

collecting duct.

*Dont fret about distinguishing

collecting ducts vs collecting tubules.

*But you will need to be able to

distinguish collecting tubules from

distal/proximal tubules.

Collecting Ducts have:

-Larger lumens

-Distinct intercellular borders

-Scalloped edges of lumens

-Many central nuclei

-Pale cytoplasm


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Note how the Thin loops have Squamous epithelium compared to the Cuboidal epithelial

cells in the thick desc/ascending loops, and cuboidal/columnar in collecting ducts.


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Kidney Stroma

(slide 28)

As you can see the stromal component in the kidney is primarily Reticular fibers

and not as predominant as in other organs.


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Ureterin or your outSlide 30Ureter

A adventitia

C circular muscle layer of ureter

L longitudinal muscle layer of ureter

LP lamina propria

V blood vessel

Q10:Transitional epithelium lines thelumen of the ureter.

Q11: Within the muscularis the

Inner layer = LongitudinalOuter layer = Circular

Therefore the section on slide 30 was

taken from the upper 2/3rds of ureter.

Q12: This arrangement is opposite of

that found in the tubular organs of the

GI tract. Hmph.


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One more look at the Transitional Epithelium lining the Ureter


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Bladder

IL inner longitudinal muscle layer of bladder

OC outer circular muscle layer of bladderOL outer longitudinal muscle layer of bladder

A adventitia

Um umbrella cell

LP lamina propria

The Bladder Mucosal layer is transitional epithelium

aka, Urothelium.

Q13: Fibrous CT composed of Elastin underlies the

mucosal layer. The fibers are refractile/pink staining.

Q14: Because the bladder is saccular, it has 3 layers

of smooth muscle in its walls. (See left)


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Q15: When fixed, the bladder in slide 31 was in the relaxed state.

Q16: Approximately 95% of bladder cancers arise from Transitional cell carcinoma.

Q17: A reliable reference listing most common causes of cancer in the US population is www.cancer.gov The US

NIH National Cancer Institute homepage..

Most Common Causes of Cancer: Bladder, Melonoma, Breast, Non-Hodgkins Lymphoma, Colon/Rectal, Pancreatic,

Endometrial, Prostate, Kidney, Skin, Leukemia, Thyroid, and Lung.Incidence differs by factors including genetics environmental exposures etc
http://www.cancer.gov/http://www.cancer.gov/

henle loop fenestrated capillary

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