Kidney -- a bean-shaped organ with renal arteries and veins entering with the ureter at the hilum.

Study the diagrams showing the overall organization of the kidney and the note the arrangement of the components in nephrons (Figs. 19-1, 19-2 and the next page) and examine the preserved-mounted, hemisected specimens of kidney, noting all the macroscopic features indicated in the diagrams.

Examine a Masson trichrome-stained section of the kidney (slide 14)

• Note the thin fibrous capsule and the fibrous/fatty support tissue at the hilum area surrounding the renal pelvis (Fig. 19-1). The orientation of this section does not clearly show the kidney's internal organization. For this examine slide 111, a section of rat kidney which unlike the human kidney is unilobular, i.e., consists of one large lobe with ducts converging in the direction of the hilum.
• With low power, identify the cortex and the medulla (Fig. 19-2).
• Near the corticomedullary junction can be several sets of arcuate arteries and veins (Fig. 19-3) cut transversely. (The veins still contain blood.) Still with low power, identify in the cortex renal corpuscles (Fig. 19-4) and then the medullary rays converging on the renal papilla and calyx (Fig. 19-1).
• Note that the largest collecting ducts (the ducts of Bellini) converge to form the renal papilla, and that this is surrounded by the calyx composed of transitional or urinary epithelium (Fig. 19-2).

What features principally distinguish renal cortex from medulla?

What constitutes a “renal lobe?”

Are the calices considered part of the medulla?

Kidney stones and the renal cortex.