In anatomy, a medullary ray (Ferrein's pyramid) is the middle part of a
cortical lobule
A cortical lobule (or renal lobule) is a part of a renal lobe. It consists of the nephrons grouped around a single medullary ray, and draining into a single collecting duct. Its near identical parallel is the rectal
The rectum is the fin ...
(or renal lobule). Each consists of a group of
nephrons
The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure ca ...
in the
renal cortex
The renal cortex is the outer portion of the kidney between the renal capsule and the renal medulla. In the adult, it forms a continuous smooth outer zone with a number of projections ( cortical columns) that extend down between the pyramids. It ...
.
Their name is potentially misleading, as "medullary" refers to their destination, not their location. They travel perpendicular to the capsule, and extend from the cortex to the medulla. They may be visualised during
urography
Pyelogram (or pyelography or urography) is a form of imaging of the renal pelvis and ureter.
Types include:
* #Intravenous pyelogram, Intravenous pyelogram – In which a contrast solution is introduced through a vein into the circulatory system.
...
.
Additional Images
File:Slide2iii.JPG, Medullary rays
File:Slide23iii.JPG, Medullary rays
References
External links
* — "Urinary System: kidney, H&E, cortex and medullary ray"
* — "Urinary System: neonatal kidney"
*
{{genitourinary-stub
Kidney anatomy