Which of the following are considered the three major renal functions?

The three major renal functions essential to kidney operation are glomerular filtration, tubular reabsorption, and tubular secretion. This is because these processes work sequentially to maintain homeostasis within the body and ensure waste products are adequately eliminated while retaining necessary substances.

Glomerular filtration is the first step, where blood plasma is filtered in the glomeruli of the kidneys, allowing water, ions, and small molecules to pass into the renal tubule, forming a filtrate. This provides a means of removing waste products and surplus substances from the blood.

Following filtration, tubular reabsorption occurs, where the kidneys selectively reclaim water, ions, and nutrients from the tubular fluid back into the bloodstream. This process is vital for conserving valuable substances and maintaining electrolyte balance and hydration levels.

Lastly, tubular secretion involves the transfer of additional substances from the peritubular capillaries into the tubular lumen. This allows for the regulation of blood pH and the elimination of certain substances that may not have been filtered effectively.

The other options depict processes related to kidney function but do not articulate the precise stages and mechanisms fundamental to how the kidneys perform their major roles in waste management and homeostasis. For example, while filtration, absorption, and secretion do describe aspects of