Calcium
From Simple English Wikipedia, the free encyclopedia
Calcium is a chemical element. Its symbol on the periodic table (a list of all the elements) is Ca. Its atomic number is 20. (The atomic number says where Calcium sits in the periodic table.)
Calcium is a soft white-gray substance. It is the 5th most common element on the earth.
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[edit] Calcium in living things
Calcium is very important for all organisms. You must eat calcium every day to have good health. If you do not eat enough calcium you can get sick. Your bones can become weak. This is called osteoporosis.
[edit] Calcium in cells
It is important to how cells work. Many cells have calcium channels on their surface. These are holes where calcium can go in the cell. The cell is told to act and it opens the holes. Calcium goes into the cell when the holes open. When it is in the cell it tells many proteins to do things. When it goes into muscle cells, it makes them contract (to become short so the muscle pulls.) When it goes into nerve cells, it makes the cell send a message. When it goes into white blood cells it makes them fight germs.
Calcium is important to cells. Too much calcium can be bad. If a cell gets more calcium than it needs it can die. This is why the amount of calcium in cells is controlled very much. Not enough calcium is bad. Cells need the right amount to work right.
Sometimes cells should die. If a cell is very old or is not healthy, it should die. This keeps the whole organism healthy. Cells know when they should die. When this happens they do apoptosis. This is also called 'programmed cell death' (planned cell death.) Cells do apoptosis by taking in very much calcium.
[edit] Calcium storage
Bones are how we store calcium. (Storage is where you keep something.) Most of the calcium in our bodies is in bones. If we need more calcium for our blood, muscles, or other tissue, it comes from the bones. If we have extra calcium it goes into bones.
[edit] Calcium regulation
Organisms need to keep calcium levels very well controlled. High calcium levels are bad. Low calcium levels are bad.
The body controls this by changing
- how much calcium we get from the food we eat
- how much calcium we lose in urine
- how much calcium is put in bones
The control of calcium in the body is called calcium metabolism.And is really important, so start eating calcium!!
The body controls calcium levels with many hormones. Calcitonin, Parathyroid hormone (acronym PTH), and Vitamin D are the most important hormones in calcium metabolism. (Vitamin D is a hormone but it is called a vitamin.)
[edit] Calcium in Industry
Calcium is also important in chemistry. It is important for making things. It is a part of cement which is needed to make concrete (a hard substance that many buildings are made from.)
Calcium is part of quicklime (calcium oxide – CaO). Quicklime is used to make paper, pottery, food, and to purify water (make it good to drink.)
