Regulation of Calcium Levels in the Body Flashcards
Which is more dangerous, hypocalcemia or hypercalcemia? Why?
Hypocalcemia (too little calcium); It causes abnormal electrical activity in nerves, leading to muscle spasms and muscle paralysis which cause death by asphyxiation
Which hormone is most important in regulating calcium levels, parathyroid hormone (PTH) or calcitonin?
Parathyroid hormone, because its job is to prevent hypocalcemia, or raise calcium levels when they are too low.
When trying to raise calcium levels, the most obvious solution is to stimulate the natural process that brings calcium into the body. What organ does PTH affect to do this?
The intestines, because calcium comes from food and enters the blood through the intestines. PTH increases this calcium absorption in the intestines by revving up Vitamin D production. Vitamin D is an essential playerin allowing calcium to enter the intestinal cells.
What does parathyroid hormone do to the kidneys that is connected to its action on the intestines?
PTH gets the kidneys involved in helping the intestines absorb more calcium because the kidneys are where Vitamin D is made. So, PTH causes the kidneys to increase Vitamin D production.
When trying to raise calcium levels, a 2nd solution is to lower(suppress) any natural process that causes calcium loss from the body. What organ does PTH affect to do this?
The kidneys, because they put calcium into the urine to send it out of the body. This is called calcium excretion or urinary loss of calcium. So, PTH causes the kidneys to decrease calcium excretion.
When trying to raise calcium levels, a 3rd solution is to stimulate the release of calcium from any storage area it might be found in. What does PTH affect to do this?
The bones, because they have “exchangeable” calcium that is easily released. The catch is that this calcium can only be released from the bone by dissolving it or breaking it down. So, PTH increases osteoclast activity-i,e., the osteoclasts dissolve more bone than usual. This is somewhat dangerous for the skeleton but a good tradeoff for the body overall because hypocalcemia can be deadly.
What is the job of the hormone calcitonin? What is unusual about it?
Calcitonin’s job is to prevent calcium levels from getting too high, called hypercalcemia. It’s unusual because it is actually not very good/effective at this!!
Do adults have high levels of calcitonin? How is this different from parathyroid hormone (PTH)?
No, adults do not have high levels of calcitonin (except during pregnancy). Only children have high levels(because of the growth of the skeleton). In contrast, adults MUST have high levels of PTH or a person will die with 3-4 days (if levels are low enough).
What is the major action calcitonin has in the body?
It decreases breakdown of bone by osteoclast (osteoclasts activity). (This is not a very effective way to lower blood calcium levels if they are too high.)
Why do calcitonin levels rise in a woman’s body during pregnancy?
The reason is because of its effect on bone. In pregnancy a woman’s body needs more calcium than usual(for the formation of the baby’s skeleton) so calcitonin protects her skeleton from being broken down too much due to the extra need for calcium.
What is another important use for calcitonin?
Because it decreases the breakdown of the skeleton, it is used as a treatment for osteoporosis and related diseases.
