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why should the decreased blood pressure result in decreased sodium concentration ? that makes no sense. it should be : low sodium can lead to low blood pressure (because of low volume) so there will be an upregulation (after sensing by the macula densa) of renin release... —The preceding unsigned comment was added by 130.60.68.45 ( talk • contribs) .
The reason NaCl supply to the PT drops is that the peritubular capillaries have less pressure due to efferent arteriole contriction. This means there is less pressure in the capillaries slowing reabsorption of solutes, and less backflow. This means less NaCl left in the PT lumen reaching the Macula Densa.
I won't change the article as I'm not 100% sure, but if someone can confirm this? 87.194.31.172 ( talk) 13:49, 9 December 2007 (UTC)
There is significant new information on the macula densa. It would be great if someone more competent than me could update the article. [1]
Alkhowarizmi ( talk) 01:35, 11 October 2021 (UTC)
References
After sensing an increased salt concentration the macula densa releases ATP from its basolateral surface. ATP causes contraction of mesangial cells and afferent arterioles (purinergic receptros, P2). ATP may also be metabolized to adenosine, which has the same effect. —Preceding unsigned comment added by 69.57.241.245 ( talk) 19:38, 14 November 2008 (UTC)
According to three physiology textbooks, including one devoted fully to renal physiology, the function of the macula densa as described here is almost bordering on incorrect. The fact of the matter is that the macula densa is an autoregulatory mechanism - not a primary sensor in terms of providing a driving force to establish renin secretion. In effect, the macula dense is a "braking" mechanism - not a primary sensor of sodium. The way this is worded here is highly suspect and in need of serious revision. —Preceding unsigned comment added by 174.54.155.108 ( talk) 19:43, 3 February 2010 (UTC)
I've just reverted an IP edit with no edit summary: [1]. The edit, beyond introducing a spelling error, seemed to radically alter the sense of the previous wording ("increased" vs. "decreased"). I've based this reversion entirely on instinct, not on biological knowledge. Someone with better information is welcome to review, or perhaps the IP who made the initial edit could explain their rationale. Franamax ( talk) 01:27, 6 December 2008 (UTC)
The function section is wordy and difficult to follow. If someone could add or edit so as to make it easier to understand that'd be great. Perhaps it could start with "if a person lacked these macula densa cells then...<consequences>.."
Thanks
The figure is correct, but isn't clear. I understand that the current figure lists most of the glomerulus, but is that all necessary when the focus should be on the macula densa? maybe a big figure of the whole nephron, with the glomerulus correctly facing the distal tubule and the macula densa circled would be good here. —Preceding unsigned comment added by 74.179.96.106 ( talk) 14:04, 26 September 2010 (UTC)
The figure is not correct. ACE is present at high levels in the lung, but this is not the primary site of conversion from Angiotensin I to Angiotensin II. ACE is present at lower but still physiologically significant levels within the kidney itself, and this is where conversion occurs. See: "Systemic Versus Local Renin Angiotensin Systems. An Overview", by Walmor C. DeMello and Richard N. Re. RENIN ANGIOTENSIN SYSTEM AND CARDIOVASCULAR DISEASE Contemporary Cardiology, 2010, 1-5, DOI: 10.1007/978-1-60761-186-8_1. — Preceding unsigned comment added by 130.15.171.64 ( talk) 02:26, 11 December 2011 (UTC)
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||
|
why should the decreased blood pressure result in decreased sodium concentration ? that makes no sense. it should be : low sodium can lead to low blood pressure (because of low volume) so there will be an upregulation (after sensing by the macula densa) of renin release... —The preceding unsigned comment was added by 130.60.68.45 ( talk • contribs) .
The reason NaCl supply to the PT drops is that the peritubular capillaries have less pressure due to efferent arteriole contriction. This means there is less pressure in the capillaries slowing reabsorption of solutes, and less backflow. This means less NaCl left in the PT lumen reaching the Macula Densa.
I won't change the article as I'm not 100% sure, but if someone can confirm this? 87.194.31.172 ( talk) 13:49, 9 December 2007 (UTC)
There is significant new information on the macula densa. It would be great if someone more competent than me could update the article. [1]
Alkhowarizmi ( talk) 01:35, 11 October 2021 (UTC)
References
After sensing an increased salt concentration the macula densa releases ATP from its basolateral surface. ATP causes contraction of mesangial cells and afferent arterioles (purinergic receptros, P2). ATP may also be metabolized to adenosine, which has the same effect. —Preceding unsigned comment added by 69.57.241.245 ( talk) 19:38, 14 November 2008 (UTC)
According to three physiology textbooks, including one devoted fully to renal physiology, the function of the macula densa as described here is almost bordering on incorrect. The fact of the matter is that the macula densa is an autoregulatory mechanism - not a primary sensor in terms of providing a driving force to establish renin secretion. In effect, the macula dense is a "braking" mechanism - not a primary sensor of sodium. The way this is worded here is highly suspect and in need of serious revision. —Preceding unsigned comment added by 174.54.155.108 ( talk) 19:43, 3 February 2010 (UTC)
I've just reverted an IP edit with no edit summary: [1]. The edit, beyond introducing a spelling error, seemed to radically alter the sense of the previous wording ("increased" vs. "decreased"). I've based this reversion entirely on instinct, not on biological knowledge. Someone with better information is welcome to review, or perhaps the IP who made the initial edit could explain their rationale. Franamax ( talk) 01:27, 6 December 2008 (UTC)
The function section is wordy and difficult to follow. If someone could add or edit so as to make it easier to understand that'd be great. Perhaps it could start with "if a person lacked these macula densa cells then...<consequences>.."
Thanks
The figure is correct, but isn't clear. I understand that the current figure lists most of the glomerulus, but is that all necessary when the focus should be on the macula densa? maybe a big figure of the whole nephron, with the glomerulus correctly facing the distal tubule and the macula densa circled would be good here. —Preceding unsigned comment added by 74.179.96.106 ( talk) 14:04, 26 September 2010 (UTC)
The figure is not correct. ACE is present at high levels in the lung, but this is not the primary site of conversion from Angiotensin I to Angiotensin II. ACE is present at lower but still physiologically significant levels within the kidney itself, and this is where conversion occurs. See: "Systemic Versus Local Renin Angiotensin Systems. An Overview", by Walmor C. DeMello and Richard N. Re. RENIN ANGIOTENSIN SYSTEM AND CARDIOVASCULAR DISEASE Contemporary Cardiology, 2010, 1-5, DOI: 10.1007/978-1-60761-186-8_1. — Preceding unsigned comment added by 130.15.171.64 ( talk) 02:26, 11 December 2011 (UTC)