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Questions and Answers
What is the correct sequence of kidney development stages from cranial to caudal?
What is the correct sequence of kidney development stages from cranial to caudal?
- Mesonephros, Pronephros, Metanephros
- Metanephros, Mesonephros, Pronephros
- Mesonephros, Metanephros, Pronephros
- Pronephros, Mesonephros, Metanephros (correct)
What abnormal condition is characterized by the absence of one or both kidneys?
What abnormal condition is characterized by the absence of one or both kidneys?
- Horseshoe kidney
- Renal agenesis (correct)
- Ectopic ureter
- Mal-rotated kidneys
Which stage of kidney development appears in the earliest week of pregnancy?
Which stage of kidney development appears in the earliest week of pregnancy?
- Mesonephros
- Metanephros
- Intermediate mesoderm
- Pronephros (correct)
What component develops from the mesonephric system?
What component develops from the mesonephric system?
During which period is urine formed and excreted into amniotic fluid?
During which period is urine formed and excreted into amniotic fluid?
What structure develops from the pronephric duct during embryonic development?
What structure develops from the pronephric duct during embryonic development?
During what weeks does the mesonephros function as a temporary kidney?
During what weeks does the mesonephros function as a temporary kidney?
Which of the following best describes the primary method of mesonephros formation?
Which of the following best describes the primary method of mesonephros formation?
What is the ultimate destination of the mesonephric duct in embryonic development?
What is the ultimate destination of the mesonephric duct in embryonic development?
What role does BMP4 play in the differentiation of the mesonephric tubules?
What role does BMP4 play in the differentiation of the mesonephric tubules?
What is the primary function of the mesonephric vesicle in kidney development?
What is the primary function of the mesonephric vesicle in kidney development?
During which week does urine production begin in kidney development?
During which week does urine production begin in kidney development?
The definitive kidney, or metanephros, develops from which two sources?
The definitive kidney, or metanephros, develops from which two sources?
What is the major outcome of the signals from the metanephric blastema (MB) to the ureteric bud (UB)?
What is the major outcome of the signals from the metanephric blastema (MB) to the ureteric bud (UB)?
Which structure does NOT form from the ureteric bud during kidney development?
Which structure does NOT form from the ureteric bud during kidney development?
The kidneys undergo a rotation during ascent. Which direction does the hilum face after this process?
The kidneys undergo a rotation during ascent. Which direction does the hilum face after this process?
Which anatomical structure separates the cloaca into urogenital sinus and anorectal canal?
Which anatomical structure separates the cloaca into urogenital sinus and anorectal canal?
Congenital anomalies may arise from issues during development. Which is related to the failure of interaction between the ureteric bud and metanephric blastema?
Congenital anomalies may arise from issues during development. Which is related to the failure of interaction between the ureteric bud and metanephric blastema?
Which part of the urogenital sinus develops into the urinary bladder?
Which part of the urogenital sinus develops into the urinary bladder?
What is the condition characterized by the fusion of lower poles of the kidneys during ascent?
What is the condition characterized by the fusion of lower poles of the kidneys during ascent?
In the early stages of nephron development, what does the renal vesicle (RV) eventually form?
In the early stages of nephron development, what does the renal vesicle (RV) eventually form?
What anatomical change occurs to the kidneys during the growth of the lumbo-sacral region?
What anatomical change occurs to the kidneys during the growth of the lumbo-sacral region?
Which of the following is a consequence of the abnormal development of the inferior vena cava (IVC)?
Which of the following is a consequence of the abnormal development of the inferior vena cava (IVC)?
Which factor is crucial for the final shaping and elongation of the nephron during its development?
Which factor is crucial for the final shaping and elongation of the nephron during its development?
Study Notes
Kidney Development Stages
- Three successive stages of kidney development occur bilaterally from cranial to caudal, adjacent to the mesonephric/Wolffian duct: pronephros, mesonephros, and metanephros.
- Pronephros (forekidney): Appears in week 4 as non-functional tubules connected to a pronephric duct; regresses by the end of week 4.
- Mesonephros (transitory kidney): Develops from week 4-10 from the nephrogenic cord, mesonephric duct, and glomerular capillary network; functions as the first excretory organ, producing urine from week 6, becoming inactive by week 10; some cells migrate to form the adrenal glands and gonads. It consists of mesonephric tubules (BMP4) connecting to the mesonephric duct.
- Metanephros (definitive kidney): Develops from week 5 onwards from two sources: the ureteric bud (collecting system) and the metanephric blastema (nephron); reciprocal inductive signals between these structures lead to the formation of the nephron, including Bowman's capsule, and the branching of the ureteric bud to form the collecting system.
Nephron Development
- The development of the nephron involves mesenchymal-epithelial interaction, forming renal vesicles (peritubular aggregates) which develop into the various parts of the nephron (Bowman's capsule, proximal and distal convoluted tubules, Loop of Henle). Signaling molecules like PAX-2 and WNT-4 are crucial for tubule lengthening.
Collecting System Development
- The ureteric bud undergoes repeated branching to form the ureters, renal pelvis, major and minor calyces, and collecting tubules. This occurs concurrently with nephron development.
Renal Ascent and Rotation
- The metanephros initially resides at the S1-S2 vertebral level; it ascends to the T12-L3 level during weeks 6-9.
- During ascent, the kidneys rotate 90 degrees, causing the hilum to face medially.
Development of the Bladder, Urethra, and Ureters
- The urorectal septum divides the cloaca into the urogenital sinus and anorectal canal.
- The urogenital sinus differentiates into three parts: the urinary bladder, the prostatic and membranous parts of the urethra in males and the entire urethra in females, and the genital tubercle.
- The ureteric buds elongate and separate from the mesonephric duct, entering the urogenital sinus to form the ureters. The mesonephric ducts form the trigone of the bladder in both sexes.
Congenital Anomalies
- Horse-shoe kidney: Fusion of the lower poles during ascent.
- Ectopic kidney: Abnormal location of the kidney due to poor development or abnormal migration of the ureteric bud.
- Malrotation: Abnormal rotation of the kidney during ascent.
- Duplex kidney/double ureter/double pelvis: Complete or incomplete duplication of the ureteric bud or metanephric blastema.
- Renal agenesis: Absence of a kidney because of failed interaction between the ureteric bud and metanephric blastema.
- Ectopic ureteral orifice: Abnormal location of the ureteral opening.
- Exstrophy of bladder: A defect in the ventral body wall.
- Aberrant renal arteries: Persistence of embryonic vessels.
- Retrocaval ureter: Abnormal development of the inferior vena cava.
- Patent urachus: Failure of the urachus to close.
Urine Production and Excretion in the Fetus
- Urine is produced and excreted into the amniotic fluid during the fetal period using the mesonephros (early fetal development) and later metanephros (definitive kidney). Oligohydramnios can occur due to problems with this process (e.g., kidney development issues).
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Description
Test your knowledge on the three critical stages of kidney development: pronephros, mesonephros, and metanephros. This quiz explores the timeline and functions of each stage in human development. Learn how these stages contribute to the formation of the definitive kidney.
