Kidney Proximal Tubule Histology. There is marked heterogeneity in the rate of progression of kidney disease over the life span and the proximal tubule displays a variety of responses to injury ultimately leading to tubule atrophy glomerulotubular disruption and formation of atubular glomeruli in glomerular tubular and toxic nephropathies see table 1 in ref. First the proximal convoluted tubule which is the longest part of the renal tubule has a simple tall cuboidal epithelium with a brush border the epithelium almost fills the lumen and the microvilli increases the surface area by 30 40 fold.
The proximal convoluted portion pars convoluta which occupies the cortical labyrinth and the straight portion pars recta in the medullary rays of the cortex and outer medulla. Seen only in cross section 1 and 2 in the cortex because of their tortuous or convoluted course simple cuboidal to columnar epithelium with an irregular often stellate shaped lumen. A kidney contains about 1 4 x 106 nephrons.
The pars recta of the proximal tubule leads the urine to the first part of the henle loop.
Proximal convoluted tubule pct. The proximal convoluted tubule is located within the renal cortex and is continuous with the capsular space. First the proximal convoluted tubule which is the longest part of the renal tubule has a simple tall cuboidal epithelium with a brush border the epithelium almost fills the lumen and the microvilli increases the surface area by 30 40 fold. The nephron is the smallest functional unit of the kidney which filters urine from the blood.