Nucleus pulposus - annulus fibrosis

[Phloston]

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Does anyone know the relative contributions of the different cartilage types comprising these structures?

I feel as though this was an important thing to know but it's slipped my mind.

 

[smartparts]

annulus fibrosis - fibrocartilage
nucleus pulposus - collagen and proteoglycans

source: Netter's Essential Histology

 

[Phloston]

I mean in terms of collagen types I, II and III.

I've had trouble finding the info online.

The reason I'm wondering is because I feel as though I had heard somewhere a long time ago that they start off as type-II but, with old age, become more type-I or -III. I can't remember. I was hoping someone has an idea...

 

[smartparts]

probably types 1 and 2 for the annulus fibrosis. dont know about the nucleus pulposus.

 

[alternatego]

I mean in terms of collagen types I, II and III.

I've had trouble finding the info online.

The reason I'm wondering is because I feel as though I had heard somewhere a long time ago that they start off as type-II but, with old age, become more type-I or -III. I can't remember. I was hoping someone has an idea...

I don't remember any of that, but what I DO remember is that intervertebral disks have a very high % of water and they dehydrate with aging, thus decreasing their size.

 

[Myxedema]

According to FA, NP consists of type II collagen. It doesn't mention AF directly, but since made of fibrocartilage, it must be type II collogen for it as well.

 

[Phloston]

According to FA, NP consists of type II collagen. It doesn't mention AF directly, but since made of fibrocartilage, it must be type II collogen for it as well.

You're right. Nucleus pulposus is right there in FA. For some reason that had slipped my mind. Thanks for pointing that out.

I guess I'm curious as to if its composition becomes more type-I or -III with time.

 

[Myxedema]

I'd pick type III: Would you expect the elderly to have more tensile strength?

 

[Phloston]

I'd pick type III: Would you expect the elderly to have more tensile strength?

It's not that as much as it is the mechanism that would lead to that..

Unless it's just degradation of -II, which leads to compensatory transcription of -III mRNAs.