When the human kidney is bivalved (cut in half lengthwise), it can be seen to have an outer cortex measuring just over 1 cm. in thickness. The remaining inner portion of the kidney is the medulla. The majority of the medulla is composed of several pyramids, numbering from 7 to 18, and usually 7 in each kidney. The pyramids are oriented with their base to the cortex and the apex pointing down into the kidney’s collection system, the renal pelvis (the medical adjective referring to kidney is “renal”).
The reference shows a sectioned kidney with these structures clearly illustrated and labeled.
The renal cortex primarily contains the Glomeruli. These are thousands of tiny vascular structures where waste products are extracted from the blood. Each glomerulus sits in a Bowman’s capsule that collects the waste and transports it into the renal tubules. The pyramids are composed mainly of renal tubules where urine is formed and transported. Urine leaves the pyramids through the papillae, entering the renal pelvis. Urine from the pelvis passes down the ureters to the urinary bladder.