Development of Urogenital System (Special Embryology)

DEVELOPMENT OF DEVELOPMENT OF UROGENITAL SYSTEMUROGENITAL SYSTEM

URINARY SYSTEMURINARY SYSTEM

Dr. Sherif Fahmy

Anatomy of Anatomy of urogenital Systemurogenital System

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Stages of Development Stages of Development of the kidney:of the kidney:

• Human kidney is developed from Human kidney is developed from intermediate mesoderm and passes intermediate mesoderm and passes through 3 stages :through 3 stages :1- 1- PronephrosPronephros2- 2- MesonephrosMesonephros3- 3- MetanephrosMetanephros

Dr. Sherif Fahmy

NotochordSomites of Paraxial mesoderm

Intermediate mesoderm

Cardiogenic area

Septum transversum

Dr. Sher i f FahmyDr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

PRONEPHROSPRONEPHROS• Appears at 4Appears at 4 thth week. In week. In cervicalcervical region, cranial region, cranial

part of intermediate mesoderm is segmented part of intermediate mesoderm is segmented into 7 nephrotomes which become cavitated to into 7 nephrotomes which become cavitated to form 7 form 7 pronephric tubulespronephric tubules..

• Each tubule has 2 ends: Each tubule has 2 ends: 1-1- lateral ends:lateral ends: join to join to form pronephric duct. form pronephric duct. 2-2- medial ends:medial ends: join the join the coelomic cavity.coelomic cavity.

• Lower end of pronephric Lower end of pronephric ducts join the cloacaducts join the cloaca..• Pronephric tubules and proximal part of its duct Pronephric tubules and proximal part of its duct

degenerate Leaving degenerate Leaving caudal part of the duct as caudal part of the duct as mesonephric duct. mesonephric duct. Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

MESONEPHROSMESONEPHROS• It appears at the It appears at the 66 thth week week as 2 bulges on as 2 bulges on

posterior abdominal wall forming ovoid posterior abdominal wall forming ovoid mesonephric ridges.mesonephric ridges.

• It is middle part of the intermediate mesoderm It is middle part of the intermediate mesoderm that lies that lies in thoracicin thoracic and and upper lumbarupper lumbar region. region.

• It is divided into segments which become It is divided into segments which become canalised to form S-shaped canalised to form S-shaped mesonephric mesonephric tubulestubules..

• Medial ends form Medial ends form internal glomeruliinternal glomeruli while lateral while lateral ends join ends join mesonephric duct mesonephric duct which open in which open in primitive urogenital sinus.primitive urogenital sinus. Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Fate of MesonephrosFate of Mesonephros• 1- 1- Tubules:Tubules:

– Males:Males: form vasa efferentia, lobules of epididymis form vasa efferentia, lobules of epididymis (head of epididymis) and paradidymis.(head of epididymis) and paradidymis.

– Females:Females: form epoophoron and paroophoron.form epoophoron and paroophoron.2- 2- Duct:Duct:-- Males:Males: Appendix of epididymisAppendix of epididymis, , Epididymis, vas Epididymis, vas

deferens, seminal vesicle, ejaculatory duct, ureter deferens, seminal vesicle, ejaculatory duct, ureter and trigone of urinary.and trigone of urinary.

- Females:Females: Gartner duct, ureter and trigone of Gartner duct, ureter and trigone of urinary bladder. urinary bladder. At the 8At the 8 thth week most of mesonephric tubules week most of mesonephric tubules degenerate.degenerate.

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

KIDNEY AND URETERKIDNEY AND URETER1- 1- Metanephros:Metanephros: • It is It is caudal part of intermediate mesodermcaudal part of intermediate mesoderm in in

the pelvic cavity. It forms the pelvic cavity. It forms metanephric capmetanephric cap (blastema) which divides into small masses (blastema) which divides into small masses following divisions of the ureteric bud. Each following divisions of the ureteric bud. Each mass is called mass is called renal vesiclesrenal vesicles..

• Each Each vesiclevesicle will form will form Bowman’s capsule,Bowman’s capsule, proximal convoluted tubule, loop of Henel and proximal convoluted tubule, loop of Henel and distal convoluted tubules.distal convoluted tubules.

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

2- 2- Ureter:Ureter:• It arises from It arises from dorsum of mesonephric ductdorsum of mesonephric duct..• It It elongates dorso-craniallyelongates dorso-cranially to be in contact with to be in contact with

metanephros which will form the metanephros which will form the metanephric capmetanephric cap..• Upper end of the ureter divides to form Upper end of the ureter divides to form 2 – 3 major 2 – 3 major

calycescalyces, which further divides into many , which further divides into many minor calycesminor calyces which divide into which divide into collecting tubulescollecting tubules..

• Each collecting tubules will be covered with a Each collecting tubules will be covered with a piece ofpiece of the the metanephric capmetanephric cap which form renal vesicles which which form renal vesicles which forms rest of the nephron except the collecting tubules forms rest of the nephron except the collecting tubules which is developed from dividing ureteric bud.which is developed from dividing ureteric bud.

• Collecting tubules Collecting tubules communicatecommunicate with the rest of the with the rest of the nephron.nephron. Dr. Sherif Fahmy

Changes of external features of Changes of external features of developing kidney:developing kidney:

• Ascend of the kidney:Ascend of the kidney: It ascends from It ascends from pelvic cavity to its adult site in the lumbar pelvic cavity to its adult site in the lumbar region on posterior abdominal wall. This is region on posterior abdominal wall. This is done by dorso-cranial elongation of the done by dorso-cranial elongation of the ureter pushing the kidney.ureter pushing the kidney.

• Change of blood supply:Change of blood supply: during ascend. during ascend.• Loss of fetal lobulation:Loss of fetal lobulation: surface of the surface of the

kidney becomes smooth.kidney becomes smooth.• Change of direction of hi lum:Change of direction of hi lum: from from

anterior to medial.anterior to medial. Dr. Sherif Fahmy

CONGENITAL ANOMALIESCONGENITAL ANOMALIESA- A- KIDNEYKIDNEY

• Renal agenesis:Renal agenesis: Unilateral or bilateral.Unilateral or bilateral.• Congenital polycystic kidney:Congenital polycystic kidney: due to failure of due to failure of

communication between collecting tubules and rest of communication between collecting tubules and rest of the nephron.the nephron.

• Horse shoe kidney:Horse shoe kidney: due to fusion between lower due to fusion between lower ends of both kidneys. Ascent is arrested at level of L3 ends of both kidneys. Ascent is arrested at level of L3 vertebra.vertebra.

• Pelvic kidney:Pelvic kidney: due to failure of ascend. due to failure of ascend.• Ectopic kidney:Ectopic kidney: abnormal site of the kidney. abnormal site of the kidney.• Aberrant renal artery:Aberrant renal artery: additional artery that additional artery that

supplying the kidney.supplying the kidney.• Persistence of fetal lobulation:Persistence of fetal lobulation: surface of the surface of the

kidney shows lobulations.kidney shows lobulations. Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

CONGENITAL ANOMALIESCONGENITAL ANOMALIESB- B- UreterUreter

• Bifid ureter:Bifid ureter: Splitting of the upper part of Splitting of the upper part of the ureter.the ureter.

• Double ureter:Double ureter: Two separate ureters Two separate ureters due to formation of 2 ureteric buds.due to formation of 2 ureteric buds.

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy