Renal System

Constricting the afferent arteriole will decrease the volume of blood entering the glomerulus and hence the blood pressure in it. All other choices will result in an increase in pressure within the glomerulus.

ADH causes more water channels (aquaporins) to be inserted in the wall of the collecting duct. Hence, the duct is more permeable to water.

The collecting ducts are in the medulla but so are the renal columns, so renal pyramids is a more specific and better choice.

Endothelial cells make up the capillary walls, while podocytes surround the endothelial cells to make up the filtration membrane.

SG is a measure of urine density (or concentration). It is the ratio of urine density to water density, so it has no units.

ADH. If the collecting ducts are permeable to water, more water will be reclaimed from the filtrate. This will decrease its volume, and there will be less diuresis and hence anti-diuretic hormone.

The thin descending limb is impermeable to urea.

Filtration due to the pressure difference between the capillary blood and fluid in the Bowman’s capsule.

The larger diameter of the afferent arteriole along with the smaller diameter of the efferent arteriole creates a high pressure in the glomerulus which facilitates filtration of dissolved material into the Bowman’s capsule.

By the time the filtrate has passed through the PCT, loop of Henle the majority of the reabsorption that is going to happen has happened. Nevertheless, the DCT and collecting duct do reabsorb some electrolytes and water.