Tuesday, October 13, 2009

Great Interactive Website

Go to this link http://www2.edc.org/weblabs/WebLabDirectory1.html

Try the interactive evolution/natural selection demos. Bookmark this link so we can use it again for genetics.
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1 comment:

  1. ChristieOctober 21, 2009 at 10:29 PM

    Not sure how to post a separate blog entry... so I'm doing this instead! Bear with me : /

    GLUCAGON VS INSULIN

    When there is a high level of blood glucose in the body, beta cells in the pancreas release INSULIN in order to stop glucose from being created.
    The insulin sends the glucose to different parts of your body, such as the muscles, to be used for energy. Glucose is stored in its inactive form, glycogen.
    Meanwhile, glucose levels are getting very low and you are getting very tired. Thus, alpha cells in the pancreas release GLUCAGON, which turns the glycogen molecules back into glucose molecules, putting the glucose back into the blood stream.

    http://biomed.brown.edu/Courses/BI108/BI108_2002_Groups/pancstems/stemcell/pancreas.gif
    *This diagram shows the pathways of insulin and glucagon from the pancreas.


    CALCIUM VS PTH

    Osteoclasts release calcium from breaking down bone particles. When too much calcium is released, calcitonin is released (from the kidneys) from the THYROID gland and blocks osteoclasts (calcium is no longer being released).
    Meanwhile, the PARATHYROID gland notices the little amounts of calcium in the body and acts up, releasing PTH. The PTH travels to where the osteoclasts are blocked and restarts them. This causes calcium levels to rise.
    *Remember, you can only absorb calcium if you are exposed to vitamin D (sunlight).

    http://faculty.irsc.edu/FACULTY/TFischer/AP1/PTH-calcitonin.jpg
    *This diagram describes the calcitonin/PTH release.

    It is important to eat healthily, making sure you not only get enough glucose for your muscles, but also enough calcium. Hypocalcemia, a disorder that results in low levels of calcium, is most common in premature newborns, but can also develop later in life. Symptoms include irritability, muscle twitches, jitteriness, tremors, lethargy, and seizures.


    Questions:

    1. What type of system do both of these events represent?
    a. Positive Feedback
    b. Homeostasis
    c. Negative Feedback
    d. Hormone Disruption

    2. Where from and when is insulin released?
    a. From alpha cells in high concentration of glucose
    b. From beta cells in high concentration of glucose
    c. From alpha cells in low concentration of glucose
    d. From beta cells in low concentration of glucose

    3. What does PTH need to work with in order to put calcium back in the bones?
    a. Calcitonin
    b. Beta Cells
    c. Alpha Cells
    d. Vitamin D



    Answers: c, b, d

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