Lecture 2: Kidney, Bladder, and Suprarenal Gland Embryo Flashcards
3 separate kidneys develop, what are they called?
1) Pronephros
2) Mesonephros
3) Metanephros
In the Intermediate mesoderm, you have a structure in which the nephron and the duct system will form. What is this structure?
Nephrogenic cord
What embryological layer gives rise to the kidneys?
Intermediate mesoderm
What is the first kidney formed, when, and where in the body, when does it degenrate; is it functional?
Pronephros during the 4th week; forms in the neck/cervical region; degenerates late 4th week; never functional
What structures move down towards the cloaca in week 4?
Pronephric ducts
When does the Mesonephros appear and function; for how long is it functional?
Appears late in 4th week; serves as interim kidney for 1st trimester (urine production); functional until about 11 weeks.
Where does the Mesonephros form?
Thoracic and Lumbar region
What will the mesonephric tubule form?
Forms the actual nephronic unit that will concentrate urine.
When and where does the Metanephros form; significance?
Forms during 5th week in pelvic region and is the true kidney.
Where does the Metanephric duct come off of and eventually becomes?
Sprouts off the mesonephric duct (aka uteric bud) and eventually becomes the ureter
What is the embryological origin of the Glomeruli (capillaries), Bowman’s capsule, and Mesonephric tubules?
Glomeruli: Somatic lateral plate mesoderm; lateral segmental arteries
Bowman’s and Mesonephric tubules: Intermediate mesorderm
What induces nephrons to grow?
The mesonephric duct induces nephrons in adjacent nephrogenic cord to grow.
What is the major component of amniotic fluid?
Fetal urine
What 2 structures does the Metanephros give us and where are the derived from?
1) Uteric bud (metanephric duct): outgrowth from mesonephric duct
2) Metanephric blastema: derived from nephrogenic cord
What 5 structures form from the Uteric bud?
1) Ureter
2) Pelvis
3) Major calyces
4) Minor calyces
5) Collecting tubules
What 4 structures form from the Metanephric blastema?
1) Renal vesicles
2) Bowman’s capsule
3) Proximal and distal convoluted tubules
4) Loop of Henle
Describe the subsequent bifurcations in the development of the collecting system?
- Uteric bud first contacts metanephric blastema and will give rise to renal pelvis
- Uteric bud bifurcates and branches/come together to form major calyces
- Branches will branch again and then combine to form the minor calyces
Nephron originates where and is surrounding what?
As a vesicle within the blastemic cap surrounding the ampulla of a collecting duct
What happens to the vesicle within the blastemic cap?
Elongates into a tube and the glomerulus forms at one end, tubule near the glomerulus will invaginate and form Bowman’s capsule
What occurs at the other end of tubule formed from the blastemic cap?
Lengthens and differentiates into the proximal convolute tubule, loop of henle, and the distal convoluted tubule
Explain unilateral renal agenesis; more common in; Dx??
- Missing one kidney, affects males more than females, and typically the left kidney is missing.
- Asymptomatic
- Dx using US if you see ONE umbilical artery
Explain bilateral renal agenesis; associated with; Tx?.
No kidneys!
- Associated with oligohydramnios, because fetal urine is not being produced and is the major component of amniotic fluid
- These infants need dialysis and kidney transplant to survive
Embryologically how do we account for unilateral agenesis?
Ureteric bud did not form or it formed and then degenerated. Without ureteric bud we get no ureteric cord or mass.
What’s duplex kidney and how does it occur embryologically?
- Having 2 ureters
- Results from abnormal division of ureteric bud
