Blood travels into the glomerulus via the afferent arteriole, explains Dr. Dawn A. Tamarkin of Springfield Technical Community College. The glomerulus is a bundle of capillaries with split pores for filtering blood. Glomerular filtration is the first step of urine production and occurs within the renal corpuscle of the kidneys.
Electrolytes, glucose, hormones, water molecules and nitrogenous waste products pass through the split pores, emptying into the glomerular capsule space as filtrate. Larger materials, such as cells and proteins, remain in the blood. The filtered blood exits the glomerulus via the efferent arteriole. Some of the filtered materials are reabsorbed by the body as the filtrate passes through the nephron loop, explains Tamarkin. Unnecessary or harmful materials, such as excessive electrolytes and waste products, exit the body as urine.