The inner portion is the renal medulla and the outside rim is the renal cortex.

内层为肾髓质，外层为肾皮质。

It's a thin crust in the center, and then the outside rim just puffs up so beautifully.

它的中心是一层薄薄的外壳，然后外面的边缘膨胀得非常漂亮。