뼈 발달에서 골격 성장판의 이해

### 골격 성장판의 이해: 층과 뼈의 성장
* 브라운 박사는 얇은 연골 띠가 특징인 긴 뼈의 중요한 부위인 **골단 성장판의 복잡성**에 대해 설명합니다.
* 🔍 성장판은 **예비 연골 영역, 증식 영역, 비대 영역, 석회화 영역, 골화 영역**의 다섯 가지 층으로 구성되어 있습니다.
* 📈 증식 영역은 **새로운 연골 조직이 생성되는 곳**이고, 비대 영역은 **연골 세포가 커져서 결국 죽는 곳**입니다.
* 💧 비대해진 세포가 죽으면 **조골 세포가 침투하여 석회화 과정을 시작하는 석회화 영역**이 이어집니다.
* 🏗 마지막으로 골화 영역은 **석회화된 연골을 층상 뼈로 재형성**하여 성장 주기를 완성합니다.
* 🐌 브라운 박사는 성장판의 기능을 **달팽이에 비유**하여 달팽이가 위로 자라면서 그 아래에 새로 형성된 뼈의 흔적을 남긴다고 설명합니다.
* 🔄 뼈의 성장은 안쪽이 아닌 가장자리에서 바깥쪽으로 일어나며, **증식 영역의 상부에서 연골 생성**이 이 과정을 주도한다는 점에 유의해야 합니다.
* 📚 브라운 박사는 시청자가 이러한 개념을 이해하여 **골격 성장판이 뼈 성장에 어떻게 기여하는지** 더 잘 이해할 수 있도록 권장합니다.

골단 성장판은 연골을 뼈로 전환하여 가장자리에서 바깥쪽으로 확장함으로써 뼈의 성장을 촉진합니다.

Hey guys, Dr. Brown here. Another little video in histology, and this time we're gonna be going over something that a lot of folks have a hard time wrapping their head around, and that is the epiphyseal growth plate. So we look at this picture of a long bone, you can see that we're kind of zoomed in on that thin band of hyaline cartilage there in the epiphysis of the bone. That's why it's called an epiphyseal growth plate. And the growth plate is actually divided into five distinct layers. There's a zone of reserve cartilage. Immediately beneath that, a zone of proliferation, meaning that's the area where we're gonna make new cartilage tissue. The zone of hypertrophy, where the cartilage cells themselves, the chondrocytes, are going to enlarge and then die off. The zone of calcification, where the holes left by the dead cartilage cells are going to be

infiltrated by osteoblasts, which are going to start to calcify the cartilage tissue. And then finally, deepest down the zone of ossification, where the calcified cartilage is remodeled into lamellar bone in the zone of ossification. So how these zones relate to the direction of bone growth is something a lot of people tend to struggle with, and so I've put together just a little animation that will hopefully make this make just a little bit more sense. Let's look at just the growth plate all by itself. The helices is called the zone of proliferation for a reason; it's going to be making new tissue. So as chondrogenesis begins in the zone of proliferation, new cartilage tissue is going to be made. Hey, zone of proliferation got to proliferate, right? Now what's going to happen next is deep down in the zone of proliferation, lower, those are the

cells that are the oldest. Those proliferated the longest time ago, and they're eventually going to begin to undergo hypertrophy. So these cells are going to undergo a morphological change, they're gonna get bigger, they're gonna get bigger. Right? They're going to continue to grow. Meanwhile, underneath these cells down here that were hypertrophied, they're going to begin to undergo calcification. So these recently hypertrophied cells begin to calcify. Notice that the zone of proliferation is still pushing up. So these cells that were in the zone of proliferation have now differentiated, and this has become the zone of hypertrophy. So the bottom part of the zone of proliferation is now not part of the zone of proliferation, it's part of the zone of hypertrophy. Likewise, the zone of hypertrophy has become the zone of calcification, and then finally down here the zone of

calcification is going to be remodeled into new bones. So the calcified cartilage is remodeled into bone, and now what was the zone of calcification is the zone of ossification. So essentially, as the zone of proliferation grows, the cells that were left behind from the previous iteration of growth in the zone of proliferation become the zone of hypertrophy. The cells that were in the zone of hypertrophy become the zone of calcification, and the cells that were in the zone of calcification become ossification. Let's kind of wrap this up with a side-by-side. So here's our original cartoon of the epiphysis growth plate, and here's the cartoon we ended up with at the end. So you can see that it has gotten longer, but it has gotten longer by extending upward...right...toward the zone of proliferation. So we can kind of think of the epiphyseal growth plate as like a

snail, and as the snail crawls along, it's gonna leave a trail of bone behind it. So that the bones are gonna...gonna...gonna...gonna...gonna...pardon me...the zones are gonna... ..once more...the bone is gonna grow toward the Epiphanes. Meaning the bones are gonna grow from the edges outward. A lot of people want to think that the bone is growing inward but that is not the case. As cartilage is being produced at the top of the zone of proliferation, everything beneath it is being turned into more bone. More cartilage is made at the top; everything beneath it becomes bone. So I hope that helped make some sense out of how those layers in the epistle growth plate contribute to bone growth, and why bone is growing in the direction it's growing. Alright, I hope that helps. Study hard. Have fun. See you later.

HSCI 4590 Histology--Epiphyseal growth plate

ETSU Online

골단 성장판은 긴 뼈의 골단에 있는 얇은 연골 띠로 예비 연골, 증식, 비대, 석회화 및 골화의 다섯 가지 층으로 나뉩니다.

각 영역은 뼈 성장에 중요한 역할을 하며, 증식 영역은 새로운 연골 조직을 생성하고 골화 영역은 석회화된 연골을 층상 뼈로 재형성합니다.

제공된 애니메이션은 이러한 영역과 뼈의 성장 방향 사이의 관계를 명확히 설명하는 것을 목표로 합니다.

가장 오래 전에 증식한 가장 오래된 세포는 비대 및 형태적 변화를 겪으며 점점 커집니다.

이렇게 비대해진 세포가 성장하면서 석회화되기 시작하고, 증식 영역은 계속 위쪽으로 밀려 올라갑니다.

증식, 비대, 석회화 영역은 역동적이며 세포가 분화되고 성장함에 따라 이 단계 사이를 전환합니다.

골단 성장판의 석회화된 연골은 석회화 영역에서 골화 영역으로 전환하면서 뼈로 재형성됩니다.

증식 영역이 성장함에 따라 남은 세포는 비대 영역이 되고, 그다음에는 석회화, 마지막으로 골화 영역이 됩니다.

이 과정을 통해 상피 성장판이 증식 영역을 향해 위쪽으로 확장되어 길이가 길어집니다.

달팽이의 움직임은 뼈의 흔적을 남기며, 안쪽이 아닌 바깥쪽 가장자리에서 성장이 일어납니다.

증식 영역의 상단에서 생성된 연골은 그 아래에서 뼈로 변합니다.

이 과정은 골단 성장판의 뼈 성장 방향을 설명합니다.