The thick ascending limb is a part of the distal straight tubule; it becomes DCT after leaving the macula densa. Feel free to correct me but that's what we were taught.
You are correct. The macula densa are specialized cells of the tick ascending limb. Refer to Medical Physiology text book by Walter Boron and Emile Boulpaep. Both are experts in the kidney. Also, the cells of the macula densa express the NKCC2 Transporter, which is expressed in the thick ascending limb. It’s generally thought that the distal convoluted tubule starts after the macula densa.
Could you explain why sodium chloride delivery to the macula densa increases with increasing GFR? Is it because the high flow rate doesn't “allow” the diluting segment (TAL) to absorb as much as NaCl as with lower flow rates?
When the GFR increases naturally the filtered load of solutes increase, causing a rise in the sodium chloride in macula densa.. triggering the TGF. Pls visit one touch pharmacology too :)
