In the kidney of mammals, the site of ultrafiltration is the

The site of ultrafiltration in the kidney of mammals is Bowman's capsule. Bowman's capsule is the first part of the nephron, which is a microscopic structure responsible for filtering blood and producing urine. Blood enters the nephron through a tiny blood vessel called the afferent arteriole, which leads into the glomerulus, a network of capillaries surrounded by Bowman's capsule. As blood flows through the glomerulus, small molecules such as water, salts, and waste products are forced out of the blood vessels and into the capsule by a process called ultrafiltration. This filtered fluid, known as glomerular filtrate, then passes through the rest of the nephron, where additional filtering and processing takes place to produce urine.