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

1. Identify 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.
2. Understand that the PCT reabsorbs a variety of substances, including ions, nutrients, and water, to maintain homeostasis.
3. Recognize that sodium ions (Na⁺) are actively reabsorbed in the PCT through sodium-potassium pumps and other transport mechanisms.
4. Acknowledge that potassium ions (K⁺) can also be reabsorbed in the PCT, although the primary site for potassium regulation is the distal convoluted tubule and collecting duct.
5. Note that amino acids are reabsorbed in the PCT through specific transporters, ensuring that these essential nutrients are not lost in urine.

Key Concepts

Proximal Convoluted Tubule (PCT)

The proximal convoluted tubule is a segment of the nephron in the kidney responsible for the reabsorption of essential substances from the filtrate back into the bloodstream. It plays a crucial role in maintaining electrolyte balance and conserving nutrients, making it vital for kidney function.

Reabsorption

Reabsorption is the process by which the kidneys reclaim water, ions, and other substances from the filtrate after glomerular filtration. This process is essential for regulating the body's fluid and electrolyte balance, ensuring that necessary compounds are not lost in urine.

Electrolytes and Nutrients

Electrolytes, such as sodium (Na⁺) and potassium (K⁺), are vital for various physiological functions, including nerve transmission and muscle contraction. Additionally, nutrients like amino acids are crucial for protein synthesis and overall metabolism, making their reabsorption in the PCT critical for health.