Week 7 - Vitamin D Feedback Loop: Explain 2

 Week 7 - Vitamin D Feedback Loop: Explain 2

As a reminder, we are discussing the following brainteaser:

osteoporosisBackground Fact: Vitamin D is important for the absorption of calcium from food.
Brainteaser: Try to reason out how low Vitamin D could worsen osteoporosis in an individual, even if that person has normal blood calcium levels.
Feedback Loop:

Picking up from the last page, we're trying to figure out how the body would find extra calcium if blood calcium levels drop, and also how that would relate to osteoporosis.

View the first few minutes of the following animation to learn about the feedback loop that begins when blood calcium levels fall (or copy and paste this address: https://www.youtube.com/watch?v=tQVzZaV9yDY)

Links to an external site.  Note that you only need to review and fully understand the portion from the start up until 2:15.

Now review the video a second time (again, just until 2:15) and try to figure out the components of the feedback loop.  That is, try to identify which cells, organs, or molecules are serving as receptors, control center, efferent pathway, and effectors.  Take out a scratch paper and try matching each role to a body part/cell/molecule!  Also consider what would be the deviation from normal and the response.  You can also refer to the bottom half of the textbook diagram below.