Question

If the diameter of the afferent renal arteriole is decreased and that of efferent renal arteriole is increased, the ultrafiltration will
A)Be faster
B)Be slower
C)Not take place
D)Take play with the same speed

Answer 1

Hint: Formation of urine includes three main steps that are glomerular filtration, reabsorption and secretion. These processes take place within the different parts of nephrons. The urine helps to excrete out nitrogenous wastes and toxic substances from the body of humans.

Complete answer:
Glomerular Filtration
The first step in urine formation is that the filtration of blood, which is administered by the glomerulus and is named glomerular filtration. On an average amount 1200 mL of blood is filtered by the kidneys per minute which constitute roughly one by fiftth of the blood pumped out by each ventricle of the guts during a minute.
The glomerular capillary vital sign causes filtration of blood through three layers, that us
The endothelium of glomerular blood vessels,
The epithelium of Bowman's capsule, and
A basement membrane between these two layers.
These three structures form the filtration membrane. The epithelial cells of Bowman's capsule called podocytes are arranged in an intricate manner so as to leave some minute spaces called filtration slits or slit pores.
This process is termed as ultrafiltration.

Now let us find solution from given options:
1.Be faster : for ultrafiltration to be faster, the diameter of afferent arteriole must be higher than that of efferent arteriole so that high pressure gradient will be maintained.
2.Be slower : if diameter of afferent arteriole is less than the efferent arteriole then ultrafiltration will take place at a slower rate due to less pressure gradient.
3.Not take place : ultrafiltration will definitely take place as pressure gradient is maintained.
4.Take place with the same speed : the speed will decrease.

Hence, the correct answer is option (B)

Note: It is the sole mode of excretion in animals which don't have glomeruli, e.g., desert amphibians, marine fishes. Tubular secretion may be a a crucial step in urine formation because it helps within the maintenance of ionic and acid-base equilibrium of body fluids.