Metanephros

General Information
Latin	metanephros
Greek
TA98
TA2
FMA
Details
System	Urinary system
Artery
Vein
Nerve
Lymphatic drainage
Precursor	Intermediate mesoderm
Function
Identifiers
Clinical significance
Notes

The metanephros is the embryological precursor of the adult kidney in vertebrates. It is the third and final stage of kidney development, following the pronephros and mesonephros. The metanephros begins to develop in the fetus around the fifth week of gestation in humans and becomes functional by the tenth week.

Development

The development of the metanephros is initiated by the interaction between the ureteric bud and the metanephric mesenchyme. The ureteric bud, an outgrowth of the mesonephric duct, invades the metanephric mesenchyme, inducing it to differentiate into the nephrons of the kidney. This process is regulated by a complex interplay of growth factors and signaling pathways.

Ureteric Bud

The ureteric bud gives rise to the ureter, renal pelvis, calyces, and the collecting ducts of the kidney. It undergoes branching morphogenesis, a process that is crucial for the formation of the renal collecting system.

Metanephric Mesenchyme

The metanephric mesenchyme differentiates into the glomeruli, proximal tubules, loop of Henle, and distal convoluted tubules of the nephron. This differentiation is driven by signals from the ureteric bud, including GDNF (glial cell line-derived neurotrophic factor) and RET receptor signaling.

Function

The metanephros is responsible for the filtration of blood, reabsorption of essential nutrients, and excretion of waste products in the form of urine. It plays a critical role in maintaining homeostasis by regulating the body's fluid balance, electrolyte levels, and acid-base balance.

Clinical Significance

Abnormal development of the metanephros can lead to congenital anomalies of the kidney and urinary tract (CAKUT), such as renal agenesis, hydronephrosis, and polycystic kidney disease. Early detection and management of these conditions are essential for preventing long-term complications.

See Also

• Pronephros
• Mesonephros
• Kidney development
• Urinary system

External Links

• [Link to additional resources]