Nephron

The renal corpuscle is composed of a tuft of capillaries called the glomerulus (blue arrows) which is surrounded by the double-walled Bowman’s capsule (red arrows).  The space of Bowman’s capsule receives the filtrate of blood.

The proximal convoluted tubule continues from Bowman’s capsule and is located in the convoluted portion of the renal cortex.  The proximal convoluted tubule constitutes the longest segment of the nephron in the cortex and, therefore, numerous sectional profiles are visible.

The proximal tubule enters the medullary ray, where it is called the proximal straight tubule.  This segment can also be called the thick descending limb of the loop of Henle.  It descends through the medullary ray of the cortex to enter the medulla.

The thin limb of Henle’s loop, continuing from the proximal straight tubule, is usually located in the medulla, forming the bend in the loop of Henle.

The ascending thick limb (sometimes called the distal straight tubule) continues from the thin limb and ascends through the medulla to enter a medullary ray of the cortex.  At the level of its parent renal corpuscle, the thick limb leaves the ray and moves into the convoluted region and contacts the afferent arteriole at the vascular pole of the renal corpuscle (black arrow).  Here, its cells are modified to form the macula densa of the juxtaglomerular apparatus.

The loop of Henle (boxes) consists of a thick descending limb (proximal straight tubule), a thick ascending limb (distal straight tubule) and a thin, looped segment (thin limb) that interconnects the two.

The continuation of the ascending thick limb beyond the juxtaglomerular apparatus is distal convoluted tubule.  It is much shorter than the proximal convoluted tubule and eventually joins with the collecting passageways.

Urine passes out of the nephron into a series of collecting tubules, consisting of connecting tubules, collecting ducts and papillary ducts.

In the convoluted region of the cortex, a distal convoluted tubule continues as a connecting tubule that arches into a medullary ray and joins a collecting duct to descend into the medulla.  Cells forming collecting ducts increase from cuboidal to columnar along their path from cortex to medulla.  The largest ducts, papillary ducts of Bellini, open into the minor calyx.

In the convoluted region of the cortex, a distal convoluted tubule continues as a connecting tubule that arches into a medullary ray and joins a collecting duct to descend into the medulla.  Cells forming collecting ducts increase from cuboidal to columnar along their path from cortex to medulla.  The largest ducts, papillary ducts of Bellini, open into the minor calyx.

In the convoluted region of the cortex, a distal convoluted tubule continues as a connecting tubule that arches into a medullary ray and joins a collecting duct to descend into the medulla.  Cells forming collecting ducts increase from cuboidal to columnar along their path from cortex to medulla.  The largest ducts, papillary ducts of Bellini, open into the minor calyx.

The medullary ray contains the straight portions of the proximal and distal tubules and the collecting ducts.

Interlobular arteries branch from arcuate arteries and travel through the center of the convoluted portions of the cortex, where they give off afferent arterioles supplying the glomerular capillaries. Interlobular arteries indicate the perimeter of the renal lobule.

Interlobular arteries branch from arcuate arteries and travel through the center of the convoluted portions of the cortex, where they give off afferent arterioles supplying the glomerular capillaries. Interlobular arteries indicate the perimeter of the renal lobule.