Question

Find the correct answers about glomerular filtrate
1. Formed continuously through ultrafiltration of blood.
2. Lipid free fluid collects in the lumen of Bowman’s capsule.
3. Protein free fluid collects in the lumen of Bowman’s capsule.
4. Formed by the process of selective reabsorption.

A. 1, 2, 3 correct
B. 1, 2 correct
C. 2, 4 correct
D. 1, 3 correct

Answer 1

Glomerular filtrate is a fluid in the lumen of the Bowman's capsule that has been drained out of the glomerulus capillaries. The filtrate consists of water, nitrogenous waste and nutrients.

Complete answer:
- Blood filtration, which is performed by the glomerulus and is termed glomerular filtration, is the first step of urine production. There are about a million complex tubular structures in each kidney, called nephrons, which are functional units. There are two sections of a nephron- the glomerulus and the renal tubule. Glomerulus is an afferent arteriole formed by a group of capillaries. The renal tubule begins with a double walled Bowman's capsule and is further divided into a proximal convoluted tubule (PCT), a loop of Henle (HL) and a convoluted distal tubule (DCT).

- On average, the kidneys process about 1100-1200 ml of blood per minute, which is nearly one-fifth of the blood pumped out per minute from each ventricle of the heart. The glomerular capillary blood pressure induces blood filtration through three layers. These are the endothelium of the glomerular blood vessels, the epithelium of the Bowman capsule and the basement membrane between these two layers.

- The epithelial cells or podocytes of the Bowman capsule are organised in a complex way to leave certain tiny gaps or filtration slits. Through these membranes, blood is filtered so precisely that nearly all the plasma constituents except the proteins move into the lumen of the Bowman's capsule. Therefore, it is regarded as an ultra-filtration process.

Thus, the correct answer is option D i.e., 1, 3 correct.

Note: The glomerular filtrate is the same as the plasma, in that it does not contain any of the larger elements, such as plasma proteins or cells. The blood components that are not filtered include blood cells, platelets and albumins that exit the glomerulus from the efferent arteriole.