As a result, bone deposition decreases due to a lack of stress, while resorption increases.

于缺少应力的作用，沉积减少，同吸收增强。

So, bone resorption usually overtakes bone formation around the 8th decade of life.

因此，人到80岁之后，吸收能力通常压制生长能力。

Over time, this resorption of calcium from the bones leaves them weak and brittle, a condition known as renal osteodystrophy.

随着间推移，这种溶生钙的过程导致变得脆弱易碎，这是肾性营养不良。

In postmenopausal osteoporosis, decreased estrogen levels lead to increased bone resorption.

在绝经后质疏松中，雌激素的减少引发了吸收的增加。

Alright, as a quick recap, osteoporosis refers to decreased bone density, on account of increased bone resorption compared to bone formation.

好！快速回顾一下：质疏松意味着密度的，自身吸收能力大于生长能力造成。

Finally, vitamin D promotes calcium absorption in the gut, so it increases serum calcium, promoting bone formation and decreasing bone resorption.

最后，维生素D促进钙在肠内的吸收，因此增加了血清钙的水平，促进生长并减弱吸收。

This is caused by increased bone resorption, which is a process that breaks bones down, eventually fast enough that it outweighs the rate of new bone growth.

这是逐渐溶蚀所引起，整个过程会造成折，最终则因速度太快，远超过的生长率。

Parathyroid hormone is produced by the parathyroid glands in response to low serum calcium, and it increases bone resorption to release calcium into the bloodstream.

顾名思义，甲状旁腺激素在甲状旁腺产生，来应对血清中过的钙水平，从而增加质的吸收来释放更多的钙进入血液。

On the other hand, calcitonin is produced by the thyroid gland in response to high serum calcium, so it opposes the action of PTH - therefore promoting bone formation and decreasing bone resorption.

另一方面，当血清中钙含量较高，甲状腺释放血钙素，来制约甲状旁腺激素的作用，从而促进的形成并减缓的吸收。