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Urine Formation
Urine Formation
The process of urine formation involves ultrafiltration, selective reabsorption and secretion.
Ultrafiltration occurs when small and soluble molecules are forced across the basement membrane of the glomerulus into the Bowman's capsule, forming the glomerular filtrate.
As this process is difficult to visualise, I crafted a modeling activity for my students and the whole cohort in order to enhance students' understanding of this concept.
Modeling ultrafilatraion worksheet_BLANK.pdfThis is a blank copy of the activity worksheet that every student had a copy of.
Slides_Modeling Ultrafiltration.pdfThis was the set of teaching slides I created to use together with the activity worksheet.
initial mixture
initial mixture
Two mixtures were prepared:
The glucose solution represented the small molecules found in blood, while the starch suspension represented the large molecules present in blood.
When iodine solution was added to starch, it resulted in a blue-black colouration, but remained brown when added to glucose solution.
filtration setup
filtration setup
This filtration setup represents the glomerulus inside the nephron (in the kidney).
There is a nylon filter attached to the bottom of the syringe that functions as the basement membrane of the glomerulus.
modeling ultrafiltration
modeling ultrafiltration
Predict the colour of the filtrate when the mixture is forced across the nylon filter.
The pressing force represents the high hydrostatic blood pressure inside the glomerulus.
The filtrate formed is colourless, which implies starch molecules are too large to pass across the nylon filter.
model setup
model setup
Eventually, students will complete an activity to compare the similarities between the model setup and the glomerulus.
Modeling Ultrafiltration.mp4video: modeling ultrafiltration
video: modeling ultrafiltration
Watch the process in this video if you are curious!
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