Connecting tubule
Encyclopedia
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.
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.
s, arch upwards before reaching the cortical collecting ducts. It is this "arcuate" feature which gives the tubule its alternate name.
and electrolyte
s, 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.
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
, the collecting tubule (CNT, or junctional tubule, or arcuate renal tubule) is a tubular segment of the renal collecting duct system
Collecting duct system
The collecting duct system of the kidney consists of a series of tubules and ducts that connect the nephrons to the ureter. It participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and antidiuretic hormone.There are several...
that connects the distal convoluted tubule
Distal convoluted tubule
The distal convoluted tubule is a portion of kidney nephron between the loop of Henle and the collecting duct system.- Physiology :It is partly responsible for the regulation of potassium, sodium, calcium, and pH...
to the cortical collecting duct.
Classification
Many sources include the connecting tubule as part of the collecting duct system. However, the embryological origin is more similar to the nephronNephron
The renal tubule is the portion of the nephron containing the tubular fluid filtered through the glomerulus. After passing through the renal tubule, the filtrate continues to the collecting duct system, which is not part of the nephron....
than it is to the rest of the collecting duct (which derives from the ureteric bud
Ureteric bud
The ureteric bud is a protrusion from the mesonephric duct during the development of the urinary and reproductive organs. It later develops into the adult kidney, except for the nephrons, which, in contrast, originate from the metanephric blastema....
), and other sources therefore classify the connecting tubule with the nephron.
Naming
Some connecting tubules, usually associated with juxtamedullary nephronNephron
The renal tubule is the portion of the nephron containing the tubular fluid filtered through the glomerulus. After passing through the renal tubule, the filtrate continues to the collecting duct system, which is not part of the nephron....
s, arch upwards before reaching the cortical collecting ducts. It is this "arcuate" feature which gives the tubule its alternate name.
Function
It participates in the regulation of waterWater
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
and electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
s, including sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
, and chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
.
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.