Arendshorst, elsa belloreuss, in handbook of cell signaling second edition, 2010. Tgf, a major mechanism by which gross filtrationabsorption mismatches are prevented, is the subject of the article by thomson et al. The macula densa is the thickening where the distal tubule touches the glomerulus the cells of the macula densa are sensitive to the concentration of sodium chloride in the. The macula densa is a region of specialized epithelial cells of the tal where there is close anatomic contact between the tal and the vascular pole of its own glomerulus. The macula densa is worth its salt article pdf available in journal of clinical investigation 1048. The macula densa participates in the regulation of renin release from juxtaglomerular granular cells. The macula densa is worth its salt pubmed central pmc. These cells are in close approximation to the juxtaglomerular vascular smooth muscle cells of the afferent arterioles of their glomeruli, and together they form what is known as the juxtaglomerular apparatus.
Role of macula densa in renal nerve modulation of renin. 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. 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 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. Role of macula densa in diureticsinduced renin release. 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. Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the. Also, keep in mind that other mechanisms, such as an increase in thirst due to atii action on the hypothalamus, that try to compensate for the low bp and try to increase blood. Macula densa cells in the distal nephron, according to the classic paradigm. In the kidney, the macula densa is an area of closely packed specialized cells lining the wall of. The juxtaglomerular apparatus is named because it is next to juxta the glomerulus.
The juxtaglomerular apparatus is a specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole. Macula densa article about macula densa by the free. The macula densa is a region of specialised cells lining the distal convoluted tubule. In the kidney, the macula densa is an area of packed specialized cells lining the wall of the distal tubule, at the point where the thick ascending limb meets the distal convoluted tubule. Quizlet flashcards, activities and games help you improve your grades. 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. A decrease in sodium chloride concentration initiates a. Single jgas, consisting of a segment of distal tubule including the macula densa, with adherent glomerulus and short vascular fragments, are dissected from rabbit. Possible role of adenosine in the macula densa mechanism. Sistema renina angiotensina aldosterona medsimples. The cells of the macula densa are sensitive to the concentration of sodium chloride in the distal convoluted tubule. However, the precise role in the reg the macula densa cells macula densa the ulation of this hormone is unknown. Macula densa definition of macula densa by medical.
However, the singling pathway of o2 production in the macula densa is not known. Ch 2526 macula densa sheet study guide by viera31 includes 15 questions covering vocabulary, terms and more. Sistema renina angiotensina aldosterona linkedin slideshare. Pd bl was recorded in order to examine how these cells sense changes in luminal nacl concentrations. It monitors tubular nacl concentrations and adjusts glomerular filtration accordingly.
The juxtaglomerular apparatus consists of three types of cells. Macula densa cell an overview sciencedirect topics. 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 sensing and signaling mechanisms of renin release.
Pdf macula densa sensing and signaling mechanisms of renin. Dal punto di vista morfologico essa rappresenta il punto di passaggio fra il segmento rettilineo e quello convoluto del tubulo distale. Benabe diuretic therapy may enhance reni releasen by various mechanisms, principally contraction of extracellular fluid volume and its effects, including a fall in arterial pressure. Renin secretion depends on nacl delivery to and reabsorption by the maculadensa cells at the end of the tal. Macula densa definition of macula densa by the free. Effects of nitric oxide on renal proximal tubular na.
Department of mathematics 719 patterson office tower lexington, kentucky 405060027 859. Role of macula densa in diureticsinduced renin release manuel martinezmaldonado, rosario gely, edilia tapia, and julio e. It is located near the vascular pole of the glomerulus and its main function is to regulate blood pressure and the filtration rate of the glomerulus. Pdf the macula densa is worth its salt researchgate. What is the function of the macula densa cells of the. The macula densa cells work the same way because they stimulate the jg cells to secrete renin. The macula densa cells are a small subset of approximately 20 cells per nephron at the distal end of the ctal of the loop of henle. 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. Als macula densa dichter fleck bezeichnet man zellen des geraden teils des distalen.
O sistema renina angiotensina aldosterona sraa exerce um papel muito. Pdf macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that. 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. It is ideally situated close to the afferent arteriole which governs glomerular filtration and the granular cells which surround the afferent arteriole and secrete renin when appropriately stimulated. Renin secretion depends on nacl delivery to and reabsorption by the macula densa cells at the end of the tal. Macula densa medical definition merriamwebster medical. Superoxide o2 enhances tubuloglomerular feedback by scavenging nitric oxide at the macula densa. The tubuloglomerular feedback mechanism of renal autoregulation is the key function of the macula densa. Macula densa control of renin secretion springerlink. In addition to tubular salt sensing, macula densa cells also sense alterations in tissue metabolism through the accumulation of the krebs cycle intermediate, succinate, in tubular fluid. An in vitro approach to the study of macula densamediated.