What does glomerular filtrate primarily contain?

Glomerular filtrate primarily contains substances found in blood plasma, with the exception of larger proteins that are too big to pass through the filtration barrier of the glomeruli in the kidneys. This filtration process separates smaller molecules, such as water, electrolytes, glucose, amino acids, and waste products like urea, from the blood while preventing the passage of larger molecules, including red blood cells and large proteins. This characteristic of glomerular filtration is essential for maintaining the body's fluid and electrolyte balance, as well as for regulating waste removal. The similarity to blood plasma allows for the efficient reabsorption of necessary substances later in the nephron while eliminating waste.