Question

question 21
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which cells within the kidney respond to changes in na+ and fluid flow rate
to utilize atp, adenosine, and nitric oxide (no) in paracrine signaling?
intercalated cells
macula densa
proximal tubule cells
principal cells

Explanation:

Macula densa cells are part of the juxtaglomerular apparatus. They detect changes in \(Na^{+}\) concentration and fluid flow rate in the distal convoluted tubule. Based on these changes, they release substances like ATP, adenosine, and nitric oxide (NO) which act in a paracrine manner. For example, if \(Na^{+}\) levels are low, they can signal to increase renin release (which is related to the regulation of the renin - angiotensin - aldosterone system). Intercalated cells are mainly involved in acid - base balance (secreting \(H^{+}\) or \(HCO_{3}^{-}\)). Proximal tubule cells are mainly for reabsorption (e.g., reabsorbing glucose, amino acids, a large amount of \(Na^{+}\), \(Cl^{-}\), \(H_{2}O\) etc.). Principal cells are mainly involved in \(Na^{+}\) and \(K^{+}\) transport (under the influence of aldosterone for \(Na^{+}\) reabsorption and antidiuretic hormone for water reabsorption in a different context than the paracrine signaling described in the question).

Answer:

Macula densa