Macula densa e renina pdf

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. Tgf, a major mechanism by which gross filtrationabsorption mismatches are prevented, is the subject of the article by thomson et al. Macula densa definition of macula densa by the free. Em resposta a diminuicao do volume sanguineo efetivo, a renina e. So in response to low bp, jg cells start the process which results in angotensin ii activation which constricts blood vessels, including the afferent arteriole supplying the nephron. Sistema reninaangiotensina renina sintetizzata, accumulata e secreta dalle cellule iuxtaglomerulari della parete dellarteriola afferente regolazione del rilascio di renina via della macula densa via dei barocettori renali via dei recettori betaadrenergici. Pdf macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors. Intraadrenal interactions in the regulation of adrenocortical steroidogenesis pdf. Macula densa cells in the distal nephron, according to the classic paradigm. The cells of the macula densa are sensitive to the concentration of sodium chloride in the distal convoluted tubule. Renin secretion depends on nacl delivery to and reabsorption by the maculadensa cells at the end of the tal. Single jgas, consisting of a segment of distal tubule including the macula densa, with adherent glomerulus and short vascular fragments, are dissected from rabbit. On the other hand, no released from the macula densa is involved in rennin secretion and tgf response via vasoconstriction of the afferent arterioles 3941.

Macula densa article about macula densa by the free. The reninangiotensin system ras, or reninangiotensinaldosterone system raas, is a. Macula densa definition of macula densa by medical. Macula densa sensing and signaling mechanisms of renin release. We isolated and perfused in vitro thick ascending limb segments with the. As shown schematically in figure figure1, 1, in every mammalian nephron, the distal tubule is attached to its glomerulus of origin at a point where normally about 80% of the filtered water and 85. The macula densa participates in the regulation of renin release from juxtaglomerular granular cells. 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. The present study reports basolateral membrane voltage pd bl measurements in macula densa cells.

O gene da renina humana tem dez exons e nove introns. If the perfusion of the juxtaglomerular apparatus in the kidneys macula densa decreases, then the juxtaglomerular cells granular cells. Now, when filtrate osmolarity is low, the macula densa cells function to dilate the afferent arteriole. Pdf macula densa sensing and signaling mechanisms of renin.

Macula densa cells are renal sensor elements that detect changes in distal tubular fluid composition and transmit signals to the glomerular vascular elements. Also contributing may be the ho2 system in maculadensa cells, with production of co and biliverdin that exert vasodilatorlike actions. 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. Macula densa medical definition merriamwebster medical. Arendshorst, elsa belloreuss, in handbook of cell signaling second edition, 2010. It monitors tubular nacl concentrations and adjusts glomerular filtration accordingly. Atividade inadequada do sistema reninaangiotensina. The macula densa is a region of specialised cells lining the distal convoluted tubule. The md releases vasodilator prostaglandins pg as pgi2 and pge2, generated by cyclooxygenase 2, which induce renin release from juxtaglomerular cells.

The macula densa is worth its salt pubmed central pmc. Dal punto di vista morfologico essa rappresenta il punto di passaggio fra il segmento rettilineo e quello convoluto del tubulo distale. The tubuloglomerular feedback mechanism of renal autoregulation is the key function of the macula densa. 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. Macula densa cell an overview sciencedirect topics. Macula densa cells detect changes in luminal sodium chloride concentration through a complex series of ion. Macula densa cells sense luminal nacl concentration via.