Name: how hormones control bone turnover
Uploaded: 2025-10-23T11:49:19.000Z
Duration: 1 min 40 s
Channel: JoVE

K12 Standards

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Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-2

Bone Remodeling

- [강사] 성인의 골격에서도뼈는 활성된 조직이며지속적으로 설계적인 변화를 겪습니다이 과정은, 뼈의 재형성이며동등한 단계로 구성되어 뼈 흡수와제거 및 새 조직의 증착을 다룹니다성숙한 뼈 세포인 골 세포가 기계적인 스트레스를 감지하면세포가 뼈 부위에 신호를 보내는데예를 들어, 대퇴골의 끝이 해당하며이는 6 개월마다 교체됩니다재흡수 과정에서, 세포 유형인 파골 세포는표면에 단단히 달라 붙습니다리소좀 효소와 수소 양성자를 분비하며유기 성분을 분해할 수 있으며침식 공동이 만들어지는 데, 이는 오래되거나손상된 모체를 소화로 일어납니다칼슘 또한 혈액에 방출되어호르몬 피드백 고리에서 제 역할을 합니다물질이 용해되면파골 세포는 세포 사멸을 통해 스스로 파괴하고뼈가 더 이상 파괴되는 것을 방지합니다전환 과정을 위해단핵 세포가 표면에 나타나다음 단계를 준비합니다형성 단계에서골아 세포가 공동으로 들어가 새로운 뼈를 증착하는데유골인 유기 모체의 골화를 통해서 일어납니다이 부분은 콜라겐 섬유가 포함되었으며구조와 유연성에 기여합니다모체의 합성 후에골아 세포는 구별되어 평평한뼈 내층 세포가 되거나골세포로 뼈에 묻히게 됩니다

크로켓, 줄리 C., 마이클 J. 로저스, 프레이저 P. 콕슨, 린 J. 호킹, 미프 H. 헬프리치."뼈 리모델링 한 눈에 보기." J Cell Sci 124, no. 7 (2011년 4월 1일): 991–98. [<a href="https://doi.org/10.1242/jcs.063032">출처</a>]

피에로, F. A., J. A. 놀타, I. E. 아다모풀로스. "Concise Review: Stem Cells in Osteoimmunology." Stem Cells (Dayton, Ohio) 35, no. 6 (June 2017): 1461–67. [<a href="https://doi.org/10.1002/stem.2625" target="__blank">소스</a>]

뼈 재형성

뼈 재형성(bone remodeling; 골 재형성)은 파뼈세포(osteoclast)에 의한 뼈 재흡수(bone resorption; 골흡수)와 조뼈세포(osteoblast)에 의한 뼈 형성(bone formation; 골형성)의 지속적이고 균형 잡힌 과정입니다. 성인의 경우, 그것은 뼈의 질량(bone mass)과 칼슘 항상성(calcium homeostasis)을 유지하는 데 도움을 줍니다. 기계적 스트레스는 정상적인 유지 관리 및 회복 과정의 일부로서 회전율을 자극할 수 있지만, 일부 호르몬도 뼈의 재형성을 조절하기도 합니다.
 
 <h4>뼈 재형성의 호르몬 제어</h4>
 
 부갑상선호르몬(parathyroid hormone, 줄여서 PTH)은 뼈 재흡수를 조절함으로써 혈중 칼슘 수치의 항상성을 유지합니다. PTH는 혈액의 낮은 칼슘 수치에 반응하여 부갑상샘(parathyroid gland)에서 분비됩니다. PTH는 조골세포를 자극해 전구세포(precursor cell)를 파골세포로 분화시키는 면역 분자를 생성합니다. 파골세포의 활성화는 뼈의 재흡수를 촉진해 광물화된 뼈 기질(matrix)을 분해하고 혈액으로 칼슘을 방출합니다. 혈중 칼슘 수치가 회복되면 음성 되먹임 고리(negative feedback loop)가 PTH의 추가 분비를 방지합니다.
 
 <h4>골다공증</h4>
 
 골다공증(osteoporosis)은 뼈 재흡수가 뼈 형성을 상회해 골밀도(bone density)가 떨어지는 질환입니다. 골다공증은 특히 갱년기 이후에 여성에게 널리 퍼져 있습니다. 이것은 뼈의 재형성에서 성호르몬인 에스트로겐이 하는 결정적인 역할 때문입니다. 에스트로겐(estrogen; 에스트로젠)은 파골세포의 형성을 제한하고 세포자연사(apoptosis)를 통해 파골세포의 사멸을 촉진합니다. 이로 인해 뼈 형성이 뼈 재흡수보다 더 높게 됩니다. 하지만 완경 여성의 경우 에스트로겐 수치가 크게 떨어져 뼈 재흡수가 뼈 형성보다 앞서게 되고 이에 따라 뼈 강도가 저하되어 골절 위험이 늘어납니다.

뼈 리모델링은 파골세포에 의한 뼈 흡수와 파골세포에 의한 뼈 형성의 지속적이고 균형 잡힌 과정입니다. 성인의 경우 ...

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KEY TERMS AND CONCEPTS

주요 용어 및 개념

how hormones control bone turnover

Bone turnover is a continuous process in which old bone is broken down and new bone is built. Osteoclasts carry out bone resorption, and osteoblasts carry out bone formation. In adults, this balanced cycle helps maintain bone mass and calcium homeostasis. Mechanical stress can also stimulate turnover as part of normal maintenance and repair.

Parathyroid hormone, or PTH, helps control blood calcium levels by increasing bone resorption when calcium is low. It is released from the parathyroid glands in response to low calcium in the blood. PTH stimulates osteoblasts to produce immune molecules that promote the differentiation of precursor cells into osteoclasts. Once osteoclasts become active, they break down the mineralized bone matrix and release calcium into the blood. When calcium levels return to normal, a negative-feedback loop reduces further PTH release.

Osteoporosis develops when bone resorption becomes greater than bone formation, which lowers bone density. It is more common in women, especially after menopause. Estrogen, the female sex hormone, helps limit the formation of osteoclasts and also promotes their destruction by apoptosis, or programmed cell death. When estrogen levels drop after menopause, bone resorption can outpace bone creation. This weakens bone strength and raises the risk of fractures.

How Hormones Control Bone Turnover

what is the skeletal system?

Human Skeleton: Bones, Cells, and Disease

The human skeleton is a living framework made of 206 bones in adults. Bones connect with cartilage, tendons, and ligaments. This system gives the body support, protects organs, and helps with movement and locomotion. The skeleton has two main parts: the axial skeleton and the appendicular skeleton. The axial skeleton has 80 bones and includes the skull, the vertebral column, and the rib cage. The cranium, or upper skull, has eight bones that enclose the brain, while the lower part of the skull...

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bone remodeling

Bone turnover is a continuous process in which old bone is broken down and new bone is built. Osteoclasts carry out bone resorption, and osteoblasts carry out bone formation. In adults, this balanced cycle helps maintain bone mass and calcium homeostasis. Mechanical stress can also stimulate turnover as part of normal maintenance and repair. Parathyroid hormone, or PTH, helps control blood calcium levels by increasing bone resorption when calcium is low. It is released from the parathyroid...

skeletal muscle anatomy

Muscle Fibers, Tendons, and Contraction

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classification of skeletal muscle fibers

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cross-bridge cycle

Calcium Control in Muscle Contraction

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motor units

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key terms and concepts

Learn how PTH and estrogen regulate bone turnover, calcium balance, and osteoporosis. Clear high school biology coverage of osteoclasts and osteoblasts.

How Hormones Control Bone Turnover | JoVE K12

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How Hormones Control Bone Turnover

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