Nephron is not only the main structural, but also the functional unit of the kidney. This is where the most important stages of urine formation take place . Therefore, information on how the structure of the nephron looks, and what specific functions it performs, will be very interesting. In addition, the features of the functioning of nephrons can clarify the nuances of the renal system
Nephron structure: renal corpuscle
It is interesting that in the mature kidney of a healthy person is from 1 to 1.3 billion nephrons. Nephron is a functional and structural unit of the kidney, which consists of the renal corpuscle and the so-called Henle loop.
The renal corpuscle itself consists of a malpigium glomerulus and a Bowman - Shumlyansky capsule. To begin with, it is worth noting that the glomerulus is actually a collection of small capillaries. Blood enters here through the delivery artery - plasma is filtered here. The remainder of the blood is excreted by the efferent arteriole.
The Bowman-Shumlyansky capsule consists of two sheets - internal and external. And if the outer sheet is an ordinary tissue of squamous epithelium, then the structure of the inner sheet deserves more attention. The inside of the capsule is covered with podocytes - these are cells that act as an additional filter. They pass glucose, amino acids and other substances, but inhibit the movement of large protein molecules. Thus, primary urine is formed in the renal corpuscle, which differs from blood plasma only in the absence of large molecules.
Nephron: structure of the proximal tubule and loop of Henle
The proximal tubule is a formation that connects the renal corpuscle and the loop of Henle. Inside the tubule has villi, which increase the total area of the internal lumen, thereby increasing the reabsorption rate.
The proximal tubule smoothly passes into the descending part of the Henle loop, which is characterized by a small diameter. The loop descends into the cerebral layer, where it bends around its own axis by 180 degrees and rises up - here begins the ascending part of the Henle loop, which is much larger and, accordingly, the diameter. The ascending loop rises to about the level of the glomerulus.
Nephron structure: distal tubules
The ascending part of the Henle loop in the cortical substance passes into the so-called distal sinuous tubule. It is in contact with the glomerulus and is in contact with the external and external arterioles. Here, the final absorption of beneficial substances is carried out. The distal tubule passes into the final section of the nephron, which in turn flows into a collecting tube that carries fluid into the renal pelvis.
Nephron classification
Depending on the location, it is customary to distinguish three main types of nephrons:
- cortical nephrons account for approximately 85% of the total number of structural units in the kidney. As a rule, they are located in the outer cortex of the kidney, which, in fact, is evidenced by their name. The structure of the nephron of this type is slightly different - the Henle loop is small here;
- juxtamedullary nephrons - such structures are located just between the cerebral and cortical layer, have long Henle loops that penetrate deep into the cerebral layer, sometimes even reaching the pyramids;
- subcapsular nephrons are structures that are located directly under the capsule.
You can notice that the structure of the nephron is fully consistent with its functions.