In the kidney, the macula densa is an area of closely packed specialized cells lining the wall of the distal tubule, at the point where the thick ascending limb of the loop of henle meets the distal convoluted tubule. It is thought that the macula densa cells are sensory cells that respond to the sodium concentration in the fluid within the distal tubule and, perhaps, to the rate of fluid flow past them. Laldosterone agit sur le metabolisme des electrolytes. The juxtaglomerular apparatus is named because it is next to juxta the glomerulus. Puede ser intervenida quirurgicamente mediante una. These cells sense the nacl content of the tubule and make changes to gfr appropriately.
Depolarization of the macula densa induces superoxide production via nadph oxidase article pdf available in american journal of physiology. Mar 28, 2009 the first step in the signal transmission process is the detection of some change in the tubular fluid environment. Macula densa definition of macula densa by the free dictionary. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
We isolated and perfused in vitro thick ascending limb segments with the. The macula densa cells of the juxtaglomerular apparatus probably serve as the sensor cells for the signal which leads to the appropriate tubuloglomerular feedback response. Beneath the macula densa cells, the basal lamina is thin with extensions from the cells passing through it. Macula densa sensing and signaling mechanisms of renin release. Macula densa cells sense luminal nacl concentration via. Macula densa cells are renal sensor elements that detect changes in distal tubular fluid composition and transmit signals to the glomerular vascular elements. Macula densa md controls on renin secretion have recently been studied by examining the renin secretory response of the isolated perfused rabbit juxtaglomerular apparatus jga. The macula of the utricle, or utricular macula is the region of the utricle that receives the utricular filaments of the vestibulocochlear nerve. The cells on the side of the tubule facing the glomerulus have a distinct appearance and constitute the macular densa figure 1.
Single jgas, consisting of a segment of distal tubule including the macula densa, with adherent glomerulus and short vascular fragments, are dissected from rabbit. Choose from 48 different sets of macula densa cells stimulate flashcards on quizlet. The macula of utricle allows a person to perceive changes in. In the kidney, the macula densa is an area of closely packed specialized cells lining the wall of the distal tubule at the point of return of the nephron to the vascular pole of its parent glomerulus, glomerular vascular pole. Degeneracion macular causas, sintomas y tratamiento.
As the distal proximal tubule rises from the renal medulla, it makes close contact with the glomerulus. Macula densa cells then signal the underlying mesangial cells, which leads to the propagation of signals to other. Macula densa cells stimulate flashcards and study sets quizlet. Macula densa control of renin secretion springerlink. This tubuloglomerular feedback mechanism plays an important role in regulating glomerular filtration rate and blood flow. Pdf depolarization of the macula densa induces superoxide. Macula densa cells detect changes in luminal sodium chloride concentration through a complex series of ion. Cox2, the source of macula densa derived prostaglandins mediating renin expression and release by the juxtaglomerular apparatus, is present at low but detectable levels in the macula densa under normal homeostatic conditions. The tgf signaling pathway involves an initial change in luminal. Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions, including renal blood flow, glomerular filtration, and renin release.
Macula densa medical definition merriamwebster medical. Edgar fermin yan quiroz trujillo 2008trujillo 2008 2. K cotransporter that is responsible for the majority. Learn macula densa cells stimulate with free interactive flashcards.
The macula densa is the thickening where the distal tubule touches the glomerulus. Synlab diagnosticos globales 902 400 442 callcenter. Arteriola aferente arteriola eferente cada uno tiene una funcion especifica. The juxtaglomerular apparatus consists of three types of cells. The juxtaglomerular apparatus also known as the juxtaglomerular complex is a structure in the kidney that regulates the function of each nephron, the functional units of the kidney. The present study reports basolateral membrane voltage pd bl measurements in macula densa cells. Sistema renina angiotensina aldosterona slideshare.