Search results
Results from the WOW.Com Content Network
In the kidney, the macula densa is an area of closely packed specialized cells lining the wall of the distal tubule where it touches the glomerulus.Specifically, the macula densa is found in the terminal portion of the distal straight tubule (thick ascending limb of the loop of Henle), after which the distal convoluted tubule begins.
The macula densa's detection of elevated sodium chloride, which leads to a decrease in GFR, is based on the concept of purinergic signaling. [ 6 ] [ 7 ] An increase in the salt concentration causes several cell signals (e.g. adenosine release) that leads to constriction of the adjacent afferent arteriole.
The macula densa is a collection of densely packed epithelial cells at the junction of the thick ascending limb (TAL) and distal convoluted tubule (DCT). As the TAL ascends through the renal cortex, it encounters its own glomerulus, bringing the macula densa to rest at the angle between the afferent and efferent arterioles.
The macula (/ˈmakjʊlə/) [1] or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo , foveola , foveal avascular zone , fovea , parafovea , and perifovea areas.
The sodium chloride levels in the urinary filtrate are sensed by the macula densa cells at the end of the ascending limb. When sodium levels are moderately increased, the macula densa releases ATP [12] and reduces prostaglandin E2 release [13] to the juxtaglomerular cells nearby. The juxtaglomerular cells in the afferent arteriole constrict ...
The point where DCT contacts the cortical thick ascending limb of the loop of Henle is called macula densa. It has tightly packed columnar cells which display reversed polarity and may monitor the osmolarity of blood. Histologically, cells of the DCT can be differentiated from cells of the proximal convoluted tubule:
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Juxtaglomerular cells secrete renin in response to a drop in pressure detected by stretch receptors in the vascular walls, or when stimulated by macula densa cells. Macula densa cells are located in the distal convoluted tubule, and stimulate juxtaglomerular cells to release renin when they detect a drop in chloride concentration in tubular ...