Which is reabsorbed by the proximal convoluted tubule cells?
a. Na⁺
b. K⁺
c. Amino acids
d. All of the above

Verified step by step guidance

Understand the function of the proximal convoluted tubule (PCT) in the nephron, which is primarily responsible for reabsorbing substances from the filtrate back into the blood.

Recall that the PCT reabsorbs a large percentage of filtered sodium ions (Na⁺) through active transport mechanisms to maintain electrolyte balance.

Recognize that potassium ions (K⁺) are also reabsorbed in the PCT, although to a lesser extent compared to sodium, helping regulate potassium homeostasis.

Remember that amino acids, which are vital nutrients, are almost completely reabsorbed in the PCT via specific transporters to prevent their loss in urine.

Conclude that since Na⁺, K⁺, and amino acids are all reabsorbed by the proximal convoluted tubule cells, the correct answer is the option that includes all of these substances.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Proximal Convoluted Tubule Function

The proximal convoluted tubule (PCT) is the first segment of the nephron responsible for reabsorbing the majority of filtered substances from the glomerular filtrate back into the bloodstream, including ions, nutrients, and water.

Reabsorption of Electrolytes

Electrolytes like sodium (Na⁺) and potassium (K⁺) are actively and passively reabsorbed in the PCT to maintain electrolyte balance and support cellular functions, with sodium reabsorption driving water and other solute reabsorption.

Reabsorption of Organic Molecules

Essential organic molecules such as amino acids are efficiently reabsorbed in the PCT through specific transporters to prevent their loss in urine, ensuring the body retains vital nutrients for metabolism and repair.

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