Search results
Results from the WOW.Com Content Network
The medullary pyramids contain motor fibers that are known as the corticobulbar and corticospinal tracts. The corticospinal tracts are on the anterior surface of the pyramids. These tracts transport motor signals that originated in the precentral gyrus and travelled through the internal capsule to the medulla oblongata and pyramids.
On either side of this fissure are raised areas termed the medullary pyramids. The pyramids house the pyramidal tracts–the corticospinal tract, and the corticobulbar tract of the nervous system. At the caudal part of the medulla these tracts cross over in the decussation of the pyramids obscuring the fissure at
The medulla consists of one or more pyramids, the bases of which start from corticomedullary border. Medulla pyramid with overlying cortex comprises the renal lobe . [ 28 ] In multilobar kidneys, the pyramids are separated from each other by dipped into the kidney areas of cortical tissue known as the renal columns . [ 61 ]
Terminations of the vasa recta form the straight venules, branches from the plexuses at the apices of the medullary pyramids. They run outward in a straight course between the tubes of the medullary substance and join the interlobular veins to form venous arcades. These in turn unite and form veins which pass along the sides of the renal pyramids.
Medullary collecting ducts converge to form a central (papillary) duct near the apex of each renal pyramid. This "papillary duct" exits the renal pyramid at the renal papillae. The renal filtrate it carries drains into a minor calyx as urine. [6] The cells that comprise the duct itself are similar to rest of the collecting system.
The medial accessory olivary nucleus (MAO) lies between the primary olivary nucleus and the pyramid, and forms a curved lamina, the concavity of which is directed laterally. The dorsal accessory olivary nucleus (DAO) is the smallest, and appears on transverse section as a curved lamina behind the primary olivary nucleus.
The pyramids contain the fibers of the corticospinal tract (also called the pyramidal tract), or the upper motor neuronal axons as they head inferiorly to synapse on lower motor neuronal cell bodies within the anterior grey column of the spinal cord. The anterolateral sulcus is lateral to the pyramids.
Between the renal pyramids are projections of cortex called renal columns. The tip, or papilla, of each pyramid empties urine into a minor calyx; minor calyces empty into major calyces, and major calyces empty into the renal pelvis. This becomes the ureter. At the hilum, the ureter and renal vein exit the kidney and the renal artery enters.