Distal convoluted tubule
Distal convoluted tubule Kidney nephron ("1st proximal convoluted tubule", "2nd distal convoluted tubule") Section of cortex of human kidney. Latin tubulus contortus distalis Gray's subject #253 1223 Precursor Metanephric blastema MeSH Distal+Kidney+Tubule
On its apical surface (lumen side), cells of the DCT have a thiazide-sensitive Na-Cl cotransporter and are permeable to Ca, via TRPV5 channel. On the basolateral surface (blood) there is an ATP dependent Na/K antiport pump, a secondary active Na/Ca transporter-- antiport, and an ATP dependent Ca transporter. The basolateral ATP dependent Na/K pump produces the gradient for Na to be absorbed from the apical surface via the Na/Cl synport and for Ca to be reclaimed into the blood by the Na/Ca apical antiport.
- It regulates pH by absorbing bicarbonate and secreting protons (H+) into the filtrate, or by absorbing protons and secreting bicarbonate into the filtrate.
- Sodium and potassium levels are controlled by secreting K+ and absorbing Na+. Sodium absorption by the distal tubule is mediated by the hormone aldosterone. Aldosterone increases sodium reabsorption. Sodium and chloride (salt) reabsorption is also mediated by a group of kinases called WNK kinases. There are 4 different WNK kinases, WNK1, WNK2, WNK3, and WNK4.
- It also participates in calcium regulation by reabsorbing Ca2+ in response to parathyroid hormone.  PTH effect is mediated through phosphorylation of regulatory proteins and enhancing the synthesis of all transporters within the distal convoluted tubule.
- Arginine vasopressin receptor 2 is also expressed in the DCT.
By inhibiting the cotransporter, thiazide diuretics increase the gradient potential for Na. This increases the activity of the basolateral Na/Ca antiport and causes the increase in calcium reclamation associated with thiazide diuretics.
The DCT is lined with simple cuboidal cells that are shorter than those of the proximal convoluted tubule (PCT). The lumen appears larger in DCT than the PCT lumen because the PCT has a brush border (microvilli). DCT can be recognized by its numerous mitochondria, basal infoldings and lateral membrane interdigitations with neighboring cells.
The point where DCT contacts afferent arteriole of renal corpuscle is called macula densa. It has tightly packed columnar cells which display reversed polarity and may monitor the osmolarity of blood.
Histologically, cells of the DCT can be differentiated from cells of the proximal convoluted tubule:
Characteristic PCT DCT Apical brush border Usually present Not present Eosinophilicity More Less Cytoplasm More Less Readily discernible nuclei Less likely More likely
1 Glomerulus, 2 proximal tubule, 3 distal tubule
- Histology at OU 35_19
- Physiology at MCG 7/7ch03/7ch03p18
- Physiology at MCG 7/7ch07/7ch07p14
- Histology at BU 16004loa
- Histology at BU 16007loa
Anatomy: urinary system (TA A08, TH H3.06, GA 11.1215) AbdomenLayersRenal tubuleFiltration Pelvis
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distal convoluted tubule — n the convoluted portion of the nephron lying between the loop of Henle and the nonsecretory part of the nephron and concerned esp. with the concentration of urine called also convoluted tubule, distal tubule * * * tubulus contortus distalis … Medical dictionary
distal convoluted tubule — noun : the convoluted portion of the vertebrate nephron that lies between the loop of Henle and the collecting tubule in intimate association with the afferent vessel, that resembles the proximal convoluted tubule in structure though lacking the… … Useful english dictionary
distal convoluted tubule — noun Date: circa 1901 the convoluted portion of the vertebrate nephron that lies between the loop of Henle and the nonsecretory part of the nephron and that is concerned especially with the concentration of urine … New Collegiate Dictionary
convoluted tubule — n 1) PROXIMAL CONVOLUTED TUBULE 2) DISTAL CONVOLUTED TUBULE * * * a channel that follows a tortuous course; see tubulus contortus distalis, tubulus contortus proximalis, and tubuli seminiferi contorti … Medical dictionary
convoluted tubule — noun Date: 1923 all or part of the coiled sections of a nephron: a. proximal convoluted tubule b. distal convoluted tubule … New Collegiate Dictionary
convoluted tubule — noun 1. : proximal convoluted tubule 2. : distal convoluted tubule * * * n. Anat. a portion of the nephron in the kidney that functions in concentrating urine and in maintaining salt, water, and sugar balance. [1945 50] … Useful english dictionary
proximal convoluted tubule — noun : the convoluted portion of the vertebrate nephron that lies between the Malpighian corpuscle and the loop of Heule, is made up of a single layer of cuboidal cells with striated borders, and is believed to be concerned especially with the… … Useful english dictionary
Tubule — A small tube. * * * A small tube. SYN: tubulus [TA]. [L. tubulus, dim. of tubus, tube] Albarran y Dominguez tubules SYN: Albarran glands, under gland. connecting t. a narrow arching t. of the kidney joining the distal convoluted t. and the… … Medical dictionary
Connecting tubule — Scheme of renal tubule and its vascular supply. Latin tubulus renalis arcuatus Gray s … Wikipedia
renal tubule — n the part of a nephron that leads away from a glomerulus, that is made up of a proximal convoluted tubule, loop of Henle, and distal convoluted tubule, and that empties into a collecting tubule * * * the fine tubular part of a nephron, through… … Medical dictionary