The kidneys are of outstanding importance. They perform a number of homeostatic functions including filtration of plasma and elimination of metabolic waste products, regulation of the composition and volume of the extracellular fluid, and regulation of blood pressure. The kidneys are also endocrine organs. Test your basic knowledge of renal physiology by taking this simple quiz.
(1) In the kidneys, foot processes of podocytes wrap around the glomerular capillaries to form part of the glomerular filtration barriers. the spaces (or gaps) between adjacent foot processes are referred to as filtration slits, and are approximately __________ in size.
(2) When considering the filtration of plasma and its components across the glomerular filtration barriers of the kidney nephrons, molecules of up to __________ are filtered (i.e., move out of the lumen of the glomerular capillaries through the filtration barriers to enter the Bowman's space).
(3) Assume that three molecules have nearly identical molecular size and shape, however, one has no net charge (neutral), one is positively charged, and one is negatively charged. If we examine the filtration of these molecules through the kidney glomerular filtration barriers, which of the following trends is likely to be observed regarding the relative amount that is filtered out of the lumen of the glomerular capillaries through the filtration barriers to enter the Bowman's space?
(4) The kidney proximal tubule represents an example of a __________ epithelium.
(5) The kidney distal tubule represents an example of a __________ epithelium.