Connecting tubule

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Connecting tubule
Scheme of renal tubule and its vascular supply.
Latin tubulus renalis arcuatus
Gray's subject #253 1223
Precursor Metanephric blastema
Dorlands/Elsevier t_22/12830099

In the kidney, the collecting tubule (CNT, or junctional tubule, or arcuate renal tubule) is a tubular segment of the renal collecting duct system that connects the distal convoluted tubule to the cortical collecting duct.

Contents

[edit] Classification

Many sources include the connecting tubule as part of the collecting duct system. However, the embryological origin is more similar to the nephron than it is to the rest of the collecting duct (which derives from the ureteric bud), and other sources therefore classify the connecting tubule with the nephron.

[edit] Naming

Some connecting tubules, usually associated with juxtamedullary nephrons, arch upwards before reaching the cortical collecting ducts. It is this "arcuate" feature which gives the tubule its alternate name.

[edit] Function

It participates in the regulation of water and electrolytes, including sodium, and chloride.

The CNT is sensitive to both isoprotenerol (more so than the cortical collecting ducts) and antidiuretic hormone (less so than the cortical collecting ducts), the latter largely determining its function in water reabsorption.

[edit] References

  • Eaton, Douglas C., Pooler, John P. (2004). Vander's Renal Physiology, 6th edition, Lange Medical Books/McGraw-Hill. ISBN 0-07-135728-9.
  • Imai M (1979). "The connecting tubule: a functional subdivision of the rabbit distal nephron segments". Kidney Int 15 (4): 346-56. PMID 513494.

[edit] External links

Urinary system - Kidney - edit
Renal fascia | Renal capsule | Renal cortex  (Renal column) | Renal medulla (Renal sinusRenal pyramids) | Renal lobe | Cortical lobule | Medullary ray | Nephron 
afferent circulation: Renal artery → Interlobar arteries → Arcuate arteries → Cortical radial arteries → Afferent arterioles → Renal corpuscle (GlomerulusBowman's capsule)

kidney tubule: Proximal tubule → Loop of Henle (Descending, Thin ascending, Thick ascending)  → Distal convoluted tubule → Connecting tubule → Collecting ducts → Duct of Bellini → Renal papilla → Minor calyx → Major calyx → Renal pelvis → Ureter

efferent circulation: Glomerulus → Efferent arterioles → Peritubular capillaries/Vasa recta → Arcuate veinInterlobar veinsRenal vein

juxtaglomerular apparatus: Macula densaJuxtaglomerular cells, Extraglomerular mesangial cells

Renal physiology
Filtration - Ultrafiltration | Countercurrent exchange | Glomerular basement membrane | Podocyte | Filtration slits | Intraglomerular mesangial cells

Hormones affecting filtration - Antidiuretic hormone (ADH) | Aldosterone | Atrial natriuretic peptide

Endocrine - Renin | Erythropoietin (EPO) | Calcitriol (Active vitamin D) | Prostaglandins

Assessing Renal function / Measures of dialysis
Glomerular filtration rate | Creatinine clearance | Renal clearance ratio | Urea reduction ratio | Kt/V | Standardized Kt/V | Hemodialysis product