Final answer:
The direct answer to the student's question is True; a dysfunction in the DCT's ability to excrete potassium can indeed lead to hyperkalemia, affecting muscle, nervous system, and cardiac function.
Step-by-step explanation:
The student's question seems to reflect a misunderstanding of renal physiology and the role of the distal convoluted tubule (DCT) in potassium excretion. The statement suggests that dysfunction of the DCT in excreting potassium could lead to hyperkalemia (elevated blood potassium levels), which is actually true. In a healthy person, potassium balance is maintained by the kidneys with excess potassium being secreted mainly in the DCT and the early part of the collecting duct. However, if the DCT loses this function, it can indeed contribute to hyperkalemia because the kidney's ability to excrete excess potassium is compromised.
Hyperkalemia affects many systems in the body. It can impair the function of skeletal muscles, the nervous system, and particularly the heart, potentially leading to fatal arrhythmias. The body relies on hormone regulation, including aldosterone, to facilitate potassium excretion. When the DCT is not functioning properly, even with an increased dietary intake of potassium, the excessive amount in the extracellular fluid (ECF) can lead to dangerous consequences such as muscle weakness, mental confusion, and cardiac issues.