Distal convoluted tubule

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Distal convoluted tubule
Kidney nephron (labeled as "2nd convoluted tubule", near top)
Image:Gray1132.png
Section of cortex of human kidney.
Latin	tubulus contortus distalis
Gray's	subject #253 1223
Precursor	Metanephric blastema
MeSH	Distal+Kidney+Tubule
Dorlands/Elsevier	t_22/12830066

The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting duct system.

[edit] Physiology

It is partly responsible for the regulation of potassium, sodium, calcium, and pH.

• It regulates pH by absorbing bicarbonate and secreting protons (H⁺) 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 chlorine (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 absorbing Ca²⁺ in response to parathyroid hormone.<ref>Kidney function - Loyola University</ref>

• Arginine vasopressin receptor 2 is also expressed in the DCT.

[edit] Clinical significance

Thiazide diuretics inhibit Na⁺/Cl^- reabsorption from the DCT.

[edit] Histology

Histologically, cells of the DCT can be differentiated from cells of the proximal convoluted tubule:

[edit] Additional images

1 Glomerulus, 2 proximal tubule, 3 distal tubule

Transverse section of pyramidal substance of kidney of pig, the bloodvessels of which are injected.

[edit] References

<references/>

[edit] External links

• Organology at UC Davis Urinary/mammal/cortex1/cortex7 - "Mammal, kidney cortex (LM, Medium)"
• 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

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