There are hundreds of people outside a roller coaster ride trying to get inside the gates to a waiting area (where hundreds more people are currently waiting) before going through another set of gates to the loading area where they will eventually access the ride. Once on the coaster, the train moves passengers to another location within the park and unloads before returning to the loading gates empty Tonight happens to be the annual fundrasing event where people are admitted to the ride through multiple, tightly regulated security gates in the front provided they bring a teddy bear to donate to the local youth shelter. People bringing large teddy bears must come in through any gate labeled 'A' multicolored teddy bears through any gate labeled "B," and fuzzy teddy bears must come through gates labeled "C." Each person must come through the same gate at the same time as the teddy bear they are going to donate when they enter. Security guards however are under strict fire-code restrictions permitting only a set number of people to occupy the interior waiting area at a particular time. This means that to get in, someone else has to move from the waiting area to the loading area. To get through the second set of gates and onto the ride, operators must come through a turnstyle at the same time that people move into the loading area. The operators then exit back to the loading area through a different door before cycling back into the turnstyle to admit more people. The teddy bears are constantly moving through the waiting area to the loading area where they are placed on the train and moved to the shelter. Tubular epithelial cel ICF This can viewed as an example of sodium at the DCT of the nephron vasa recta potassium and the riders to the The coupled movement of operators to the is an example the basolateral membrane diffusional gradient ions reabsorption The is an example of the ICF of the tubular epithelial cell, the can be viewed as the interstitial fluid, and the people outside on the street are currently positioned in an representation of the The teddy bears represent the many different types of that are cotransported across the of the tubular epithelial cells which must be accompanied by a second solute in crossing the membrane. Rider movement into the waiting room could be viewed as crossing the and rider movement into the loading area is an example of the apical membrane sodium organic macromolecules tubular lumen ATP The security guards are examples of the of the while the rider moving into the loading area would be and the operator represents exchanging across the Each rider represents a molecule of and the requirement of having an open space in the waiting area exemplifies a diffusional gradient, required for passage from outside to the facilitated cotransporters Na K-ATPase pump loading area The symbolism of the roller coaster returning empty demonstrates a from the interstitial fluid to the filtration waiting area Reset secretion