The funnel-shaped part in front of the nephron is called Malpighian body. Its diameter is 200 microns. It consists of two parts. These are-
(i) Bowman’s capsule: The cup-like part located in the Malpighian body is called Bowman’s capsule. Its wall diameter is 0.2 mm. It is covered by squamous epithelium cells. Visceral and parietal layers. The outer layer is called parietal and the inner layer is visceral. The parietal layer is composed of epithelial cells. The visceral layer is composed of podocyte cells with flagella. Podocyte cells have finger-like pedicels at their free ends. Due to the position of the pedicels numerous pores are formed in the visceral layer. These holes are called filtration pore. Glomerular filtrate enters Bowman’s capsule through these pores. The space between the parietal and visceral layers is called capsular space. It is named Bowman’s capsule after Sir William Bowman.
(ii) Glumerulas: The bundle of blood vessels located in Bowman’s capsule is called glomerulus. An afferent arteriole from the renal artery enters Bowman’s capsule and divides into a network of 50-60 capillaries to form the glomerulus. Later these capillary networks join to form the efferent arteriole and exit Bowman’s capsule. The diameter of the afferent artery is 50 mm and the diameter of the efferent artery is 25 mm. Due to the difference in the diameter of the two arteries, the blood pressure in the glomerulus is higher. This blood pressure helps in the formation of urine. Glomerulus acts as ultra-filter and causes ultrafiltration.