Medullary ray

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The medullary ray is the middle part of the cortical lobule or renal lobule, consisting of a group of straight tubes to the collecting ducts.

Their name is potentially misleading -- the "medullary" refers to their destination, not their location. They are located only in the renal cortex, and not in the renal medulla.^[1]

Medullary rays can also refer to a characteristic found in woods. In this context the term refers to radial sheets or ribbons extending vertically through the tree across and perpendicular to the growth rings. Also called pith rays or wood rays, these formations of primarily parenchyma cells allow the radial transmission of sap. In quartersawn material, where the wood is cut into boards with the growth rings roughly perpendicular to the face of the board, the medullary rays often produce beautiful figure such as silver grain, medullary spots, pith flecks, etc.^[2]

[edit] References

[edit] External links

• medullary+ray at eMedicine Dictionary
• Histology at BU 16003loa - "Urinary System: kidney, H&E, cortex and medullary ray"
• Histology at BU 15901loa - "Urinary System: neonatal kidney"
• UIUC Histology Subject 1008

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e Urinary system – Kidney Layers Renal fascia • Renal capsule • Renal cortex  (Renal column) • Renal medulla (Renal sinus, Renal pyramids, medullary interstitium) • Renal lobe • Cortical lobule • Medullary ray • Nephron Afferent circulation Renal artery → Segmental arteries → Interlobar arteries → Arcuate arteries → Cortical radial arteries → Afferent arterioles → Renal corpuscle (Glomerulus, Bowman's capsule) Renal tubule Proximal tubule → Loop of Henle (Descending, Thin ascending, Thick ascending) → Distal convoluted tubule → Connecting tubule → Collecting ducts → Duct of Bellini → Renal papilla → Minor calyx → Major calyx → Renal pelvis → Ureter Efferent circulation Glomerulus → Efferent arterioles → Peritubular capillaries / Vasa recta → Arcuate vein → Interlobar veins → Renal vein Juxtaglomerular apparatus Macula densa • Juxtaglomerular cells • Extraglomerular mesangial cell Filtration Glomerular basement membrane • Podocyte • Filtration slits • Intraglomerular mesangial cell • Tubular fluid Renal physiology Acid base physiology • Fluid balance