Interactive Clinical Quiz
A 24-year-old primigravida at 27 weeks of gestation presents after a biophysical profile reveals a low amniotic fluid index. Her pregnancy is complicated by gestational diabetes mellitus, managed with insulin.
📋 Fetal Ultrasonography
Fetal ultrasonography demonstrates bilateral absence of kidneys. The physician explains that the condition likely results from abnormal interaction between the ureteric bud and the metanephric mesenchyme.
👉 Question: Renal Embryology
Under normal circumstances, which of the following structures arises from the ureteric bud?
A. Proximal convoluted tubule
B. Glomeruli
C. Collecting system
D. Distal convoluted tubule
E. Loop of Henle
✅ Correct Answer:
C. Collecting system.
📚 Expert Detailed Answer and Rationale:
During renal development, the ureteric bud and metanephric mesenchyme interact through reciprocal induction, which is essential for proper nephron formation. Failure of this process, as seen in this patient with bilateral renal agenesis, leads to oligohydramnios and Potter sequence.
C. ✅ Collecting system – The ureteric bud gives rise to the entire collecting system of the kidney, which includes the collecting ducts, minor and major calyces, the renal pelvis, and the ureters.
A, B, D, E. ❌ Other nephron parts – The glomeruli, proximal convoluted tubule, loop of Henle, and distal convoluted tubule are all components of the nephron that are derived from the other embryological structure, the metanephric mesenchyme (or blastema).
🧠High-Yield Points:
- 💡 Ureteric Bud Derivatives: Collecting ducts, calyces, renal pelvis, ureter.
- 💡 Metanephric Mesenchyme Derivatives: Glomerulus to Distal Convoluted Tubule (DCT).
- 💡 Pathology: Failure of the ureteric bud to develop leads to renal agenesis.
- 💡 Clinical Consequence: Bilateral agenesis causes oligohydramnios, leading to Potter sequence (pulmonary hypoplasia, limb deformities, characteristic facies), a condition incompatible with life.
📖 Read More on: Renal Embryology
💡 Clinical Challenge / Follow-Up:
A newborn presents with a palpable abdominal mass. An ultrasound reveals a severely dilated renal pelvis and calyces, with a normal-caliber ureter distally.
Your Challenge:
- What is the most likely diagnosis?
- This condition is caused by an obstruction at what specific anatomical location?
✅ Answer:
-
The diagnosis is Congenital Hydronephrosis.
-
The obstruction is at the ureteropelvic junction (UPJ), the point where the renal pelvis (from the ureteric bud) joins the ureter. This is the most common cause of urinary tract obstruction in newborns.
0 Comments