The Urinary System Essay
One of the major functions of the …show more content…
Blood reaches the kidney through the renal arteries, a branch of the aorta. The path from the renal artery to the glomerulus runs as follows: lobar artery, interlobar artery, arcuate artery, interlobular artery, and afferent arterioles. "Afferent" means that the arteriole is carrying blood toward the glomerulus.
Small openings called fenestrations fill the capillaries that make up the glomerulus. Fenestrations allow tiny particles and water to pass into the filtrate. Surrounding the glomerulus are cells called podocytes. The interlocking pedicels (foot processes) of these cells surround the capillaries to form the filtration barrier. This barrier prevents the passage of blood cells, platelets, and protein molecules into the filtrate. Seven types of matter are small enough to pass through the filtration barrier: blood plasma (the liquid part of blood), glucose, amino acids, potassium, sodium, chloride, and urea (nitrogenous waste).
Some materials in filtrate are needed to maintain homeostasis (a stable internal environment); the reabsorption process returns these materials to the bloodstream. Reabsorption begins after blood leaves the glomerulus through the efferent arteriole. "Efferent" means that the arteriole is carrying blood