Calcitonin hormone confusion

[ilovemedi]

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No idea why i'm confused... I'm blanking out, even though it's suppose to be easy.

Goal of calcitonin is to lower blood Ca2+ levels. It can do it by:

• 1 Inhibits osteoclast activity in bones[8]
• 2 Inhibits renal tubular cell reabsorption of Ca2+ allowing it to be excreted in the urine[9][10
• 3 Inhibits Ca2+ absorption by the intestines[7]

I get the first two, but don't get #3: how does inhibiting Ca+ absorption at the intestines DECREASES Ca+ at the blood level. If it inhibits absorption by intestines, doesn't it flow back to bloodstream, thus increasing Ca+ levels? Or does absorption of intestines lead to Ca2+ to flow to blood stream? Am I visualizing this wrong?

 

[SpaceBuff12]

If you didn't absorb dietary Ca2+ it would be voided in the stool.

 

[ilovemedi]

If you didn't absorb dietary Ca2+ it would be voided in the stool.

Go it. Thanks. I guess my mind was blanking... been a long day O.O

 

[dudewheresmymd]

remember anything in the lumen of the GI is excreted as feces. the lumen of the GI and respiratory tract is considered "outside" the body.