Formation of Urine Story
Ultrafiltriation occurs in the _______________________ Capsule, where a larger diameter _______________________
arteriole leads into the _______________________, a ball of capillaries, which leads to a narrower efferent arteriole.
This creates a high pressure system, where leaky capillaries, lined with _______________________, filters all but large
proteins and cells from the blood. 1/5th of the fluid in the blood leaves the bloodstream and is captured by the
Bowman’s capsule, forming a liquid called _______________________. As the filtrate flows into the
_______________________ convoluted tubule, positively charged _______________________ ions are pumped into
the space surrounding the PCT, using ATP from the bloodstream. _______________________ is cotransported with the
sodium, allowing the body to reabsorb most of the sugar consumed during digestion. Water flows via
_______________________ out of the tubule into the peritubular capillaries, reclaiming a large amount of the water
lost during ultrafiltration. Negatively charged ions, _______________________ and phosphate, are attracted to the
positively-charged sodium, flowing out through diffusion as well.
In the _______________________ loop of Henle, water leaves the tubule and enters the peritubular capillaries via
osmosis, attracted to the high concentration of _______________________ ions in the surrounding interstitial spaces.
As the filtrate continues to the ascending loop of Henle, it grows more _______________________. The ascending loop
of Henle is impermeable to water, but permeable to _______________________ and chloride ions, which are pumped
out of the filtrate to maintain the high concentration in the deeper regions of the kidney, the
_______________________.
Within the distal convoluted tubule, final modifications are made to the filtrate, depending on the needs of the body. To
help maintain the pH of the body, _______________________ ions may be pumped in, as well as potassium ions and
urea. _______________________ are also secreted into the distal convoluted tubule, which is why drug tests often
involve urine tests.
The filtrate from several nephrons collects into a common _______________________ duct/tubule. This tubule is
selectively permeable to _______________________, depending on the needs of the body. Hormones dictate whether
water can diffuse out of this tube or not.