Final answer:
The renal medulla is the most susceptible part of the kidney to hypoxia.
Step-by-step explanation:
The most susceptible part of the kidney to hypoxia is the renal medulla. The renal medulla is the inner region of the kidney, and it contains the renal pyramids. The pyramids have long loops of Henle that extend into the medulla and are responsible for concentrating urine. These structures require a high oxygen supply, and therefore, they are more susceptible to hypoxia when blood flow is compromised.