The artery lies on the boundary between the cortex and medulla of the kidney.
A) cortical radiate
B) arcuate
C) lobar
D) interlobar
The correct answer and explanation is :
Correct Answer: B) Arcuate
Explanation (Approximately 300 Words):
The arcuate artery is the blood vessel that lies at the boundary between the cortex and medulla of the kidney.
To understand this, it’s helpful to review the vascular anatomy of the kidney:
- Renal Artery: Blood enters the kidney via the renal artery, which branches from the abdominal aorta.
- Segmental and Lobar Arteries: The renal artery first divides into segmental and then lobar arteries as it enters the renal hilum.
- Interlobar Arteries: These branch from the lobar arteries and travel between the renal pyramids, through the renal columns, toward the cortex.
- Arcuate Arteries: At the corticomedullary junction—the boundary between the cortex and medulla—the interlobar arteries arch over the bases of the renal pyramids. These arching vessels are the arcuate arteries, which run perpendicular to the interlobar arteries.
- Cortical Radiate (Interlobular) Arteries: Branching off from the arcuate arteries, these extend up into the cortex, supplying glomeruli and other cortical structures.
The positioning of the arcuate arteries at the base of the renal pyramids places them exactly at the interface between the cortex and medulla, which is crucial for renal perfusion. This strategic location allows the arcuate arteries to serve as a vascular platform for delivering blood to the superficial cortex via the cortical radiate arteries and indirectly to the medulla via the vasa recta, which descend from efferent arterioles.
Other options:
- Cortical radiate arteries (A): Located within the cortex, not at the boundary.
- Lobar arteries (C): Located deeper, near the renal pelvis and medulla.
- Interlobar arteries (D): Run between pyramids, not on the boundary.
Thus, the arcuate artery (B) is the correct answer due to its distinct position at the cortico-medullary junction.