biology question from EK 1001

[batista_123]

1. it says "a calcium channel blocker will cause a decrease in blood calcium by inhibiting absorption"
anybody know what this means? where are these calcium channels located? if on the cell membrane, arent they used to bring calcium from the blood into the cell? then if we block them, the calcium cannot come into the cell, it will stay in the blood, so increase not decrease??
what are calciium channels, i have never heard of these

2. it says birth control pills mimick estrogen and progesterone. they prevent the LH surge by the anterior pituitary and thereby suppress ovulation. This doesnt make sense to me. estrogen causes the LH surge, right? so if you give someone a drug that looks like estrogen, shouldnt that also cause the LH surge, not prevent it?

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[BloodySurgeon]

Birth control pill supply a steady level of estrogen and in most cases progesterone. A steady level of estrogen will prevent a LH surge and ovulation and progesterone causes a thickening of the uterus that works as a blockage for sperm to enter the fallopian tube. FSH and LH are released when the body notices a shortage of esterogen or progesterone normally when too much is released at the 14 day of menstration.

 

[JohnnytheNomad]

1. it says "a calcium channel blocker will cause a decrease in blood calcium by inhibiting absorption"
anybody know what this means? where are these calcium channels located? if on the cell membrane, arent they used to bring calcium from the blood into the cell? then if we block them, the calcium cannot come into the cell, it will stay in the blood, so increase not decrease??
what are calciium channels, i have never heard of these

the fastest way to modulate the blood calcium is via the absorption from the calcium phosphate bone matrix. if we block the calcium channels we prevent the transfer of calcium from osteoclasts to the blood stream. Meanwhile, muscle and nervous tissue use up their stores and can't contract or conduct respectively. This is why CCBs are used to lower blood pressure via smooth muscle relaxing in the blood vessels and muscle relaxing mainly myocardium because the gap junctions don't function correctly.

 

[JohnnytheNomad]

Birth control pill supply a steady level of estrogen and in most cases progesterone. A steady level of estrogen will prevent a LH surge and ovulation and progesterone causes a thickening of the uterus that works as a blockage for sperm to enter the fallopian tube. FSH and LH are released when the body notices a shortage of esterogen or progesterone normally when too much is released at the 14 day of menstration.

The point of maintaining a steady level is important because the esterdiol surge itself is what causes LH surge, so if you can keep it at bay you're okay.