Biological Systems MCAT Practice Exam

How does estrogen affect bone health in females?

1. Inhibits bone resorption

2. Increases bone density exclusively

3. Promotes bone degeneration

4. Stimulates muscle growth

The correct answer is: Inhibits bone resorption

Estrogen plays a crucial role in maintaining bone health in females, particularly in regulating the balance between bone resorption and bone formation. One of the primary mechanisms through which estrogen exerts its positive effects on bones is by inhibiting bone resorption, the process by which osteoclasts break down bone tissue and release minerals into the bloodstream. Estrogen acts on osteoclasts as well as osteoblasts (the cells responsible for bone formation). It helps to decrease the lifespan and activity of osteoclasts, resulting in a reduced rate of bone resorption. This inhibition is essential to maintain bone density and overall skeletal integrity, especially during the years of peak bone mass in young adults and post-menopause when estrogen levels significantly decline. In contrast to the idea of increasing bone density exclusively, while estrogen does contribute to bone density, its function is much broader, involving a complex interplay of bone remodeling where it prevents excessive bone loss rather than solely increasing density. Additionally, promoting bone degeneration and stimulating muscle growth are not direct actions of estrogen in the context of bone health; rather, muscle strength and function are important for supporting bone health but do not directly relate to estrogen's role in preventing bone loss.