KIDNEY and Its Ducts

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KIDNEY

AND ITS DUCTS

DEVELOPMENTAL BIOLOGY


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Pronephros

MesonephrosMetanephros


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Origin/Specification of the organ

Source: Dressler, Gregory R. 2009. Advances in early kidney specification, development andpatterning. Development 136, 3863-3874. doi:10.1242/dev.034876


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Origin/Specification of the organ



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LIM-type homeobox gene Lhx1

Origin/Specification of theorgan

Odd-skipped related gene Osr1

Pax2 and Pax8

> LIM-typehomeobox

` gene Lhx1>Odd-skipped

related gene

Osr1

> Pax2 and Pax8

Gene Expression Mutant phenotype

Osr1 LPM, IM Posterior structures fail to

developLhx1 LPM,ND No nephric duct, no kidneys

Pax2 IM,ND No mesonephric tubules, nometanephros

Pax2/Pax8 IM No nephric duct, no kidneys



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Intermediate mesoderm specification

along the mediolateral axis

BMP signal

activin and retinoic acid

Intermediate mesoderm specificationalong the anteroposterior axis


Antagonistic signal

Hox genes Hox 11 genes


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Stages of formation

Three groups

Pronephros-first appratus seen-analogous to kidneys of primitive fish

Mesonephros-second set of primitive kidneys

-analogous to kidneys of amphibians Metanephros third set

-permanent kidneys

Formation of Kidney


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In the first stage represented (Fig. 51, A)

the pronephric ducts of either side are

formed first at the level of the pronephric

tubules and then extend caudad,

eventually reaching and opening into the

cloaca

In their growth the mesonephric tubules

extend toward the pronephric ducts and

soon open into them (Fig. 51,B

).Meanwhile the pronephric tubules begin to

degenerate.Thus the ducts which

originally arose in connection with the

pronephros are appropriated by the

developing mesonephros.(Fig. 51 , C).

These outgrowths form the ducts of the

metanephroi.They grow cephalo-laterad

and eventually connect with the thirdgroup of tubules developed from theintermediate mesoderm, the metanephric

tubules (Fig. 51, D).

Patten,B.M. (1920). The Early Embryology of the Chick.


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Patten,B.M. (1920). The EarlyEmbryology of the Chick.


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Differentiation


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expandsexpands toto severalseveral budsbuds thatthat willwill formform thethe

rudimentsrudiments ofof renalrenal pelvispelvis andand renalrenal calycescalyces..

givegive riserise toto thethe collectingcollecting ductduct systemsystem ofof thethe

kidneykidney..

aa portionportion ofof thethe diverticulumdiverticulum willwill givegive riserise toto thethe

ureterureter (later(later onon thethe urinaryurinary bladder)bladder)..


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continuecontinue toto elongateelongate andand formform thethe partsparts ofof thethe nephronnephron

(proximal(proximal tubules,tubules, loopsloops ofof HenleHenle andand thethe distaldistal convolutedconvoluted

tubules)tubules)..

becomebecome arrangedarranged intointo renalrenal pyramidspyramids..

givegive riserise toto BowmansBowmans capsulecapsule..


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itsits lobulatedlobulated conditioncondition continuescontinues toto existexist somesome timetime afterafter

birthbirth andand tracestraces maymay stillstill bebe foundfound eveneven inin thethe adultadult..


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Anomalies

Absence of single kidney

Ectopic kidney


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Horseshoe kidney


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Unilateral fusion


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Thank you very

much

KIDNEY and Its Ducts

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