# What is the largest structure in the body that is not composed of cells? **URL:** \ **Category:** Factual Questions\ **Created:** [September 1, 2006, 1:18pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062 "2006-09-01T13:18:38Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [September 1, 2006, 1:18pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/1 "2006-09-01T13:18:38Z")
Hair and nails arent made of living cells, but, as i understand it, they are made of layers of dead cells that have become filled with keratin. So what is the largest structure that is not composed of cells at all? ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [September 1, 2006, 1:33pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/2 "2006-09-01T13:33:09Z")
[QUOTE=misterW] Hair and nails arent made of living cells, but, as i understand it, they are made of layers of dead cells that have become filled with keratin. So what is the largest structure that is not composed of cells at all? [/QUOTE] A better question: \*\*Is there any structure in the body that is not composed of cells? \*\* WAG Bone(s)? ---
**Author:** ![motomoon](https://avatars.discourse-cdn.com/v4/letter/m/a9adbd/32.png) [@motomoon](https://boards.straightdope.com/u/motomoon)\ **Post date:** [September 1, 2006, 1:40pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/3 "2006-09-01T13:40:39Z")
If not strictly bones, my WAG: teeth or possibly the fluid in the eyeballs? ---
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [September 1, 2006, 1:49pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/4 "2006-09-01T13:49:44Z")
[QUOTE=spingears] A better question: \*\*Is there any structure in the body that is not composed of cells? \*\* WAG Bone(s)? [/QUOTE] well, not a major structure certainly. i know bones have cells in them, although i dont think the bulk of bones is living cells – so i wouldnt count bones. I’m just wondering if there any non cellular structures that are bigger than enzymes or hormones or things like that. cells have proteins sticking out all over them…maybe some part of the extracellular matrix is the biggest noncellular structure? ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [September 1, 2006, 1:57pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/5 "2006-09-01T13:57:40Z")
Bone cells are called [osteoblasts](http://en.wikipedia.org/wiki/Osteoblasts) (bone builders) and [osteoclasts](http://en.wikipedia.org/wiki/Osteoclasts) (bone dismantlers (or “carvers”, as was my mnemonic in anatomy class.)) The two together move around osteoids (collagen, mostly) and minerals. So portions of the bone are not, strictly speaking, cells, but cells are all over the bones. You couldn’t really carve out a piece of bone and not find cells in it. I think hair and nails might be it, if we’re not talking something like fecal matter or urine. ---
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [September 1, 2006, 2:05pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/6 "2006-09-01T14:05:26Z")
[QUOTE=WhyNot] Bone cells are called [osteoblasts](http://en.wikipedia.org/wiki/Osteoblasts) (bone builders) and [osteoclasts](http://en.wikipedia.org/wiki/Osteoclasts) (bone dismantlers (or “carvers”, as was my mnemonic in anatomy class.)) The two together move around osteoids (collagen, mostly) and minerals. So portions of the bone are not, strictly speaking, cells, but cells are all over the bones. You couldn’t really carve out a piece of bone and not find cells in it. I think hair and nails might be it, if we’re not talking something like fecal matter or urine. [/QUOTE] right, but i wasnt counting hair and nails, though, because they are made from dead cells. i was looking for an entirely noncellular structure. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [September 1, 2006, 2:15pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/7 "2006-09-01T14:15:50Z")
[QUOTE=misterW] right, but i wasnt counting hair and nails, though, because they are made from dead cells. i was looking for an entirely noncellular structure. [/QUOTE] Ah. Would you consider [blood plasma](http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0006861.html) to be a “structure”? Technically, blood is considered connective tissue in most textbooks. ---
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [September 1, 2006, 3:04pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/8 "2006-09-01T15:04:13Z")
[QUOTE=WhyNot] Ah. Would you consider [blood plasma](http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0006861.html) to be a “structure”? Technically, blood is considered connective tissue in most textbooks. [/QUOTE] hmmm. interesting. plasma is kind of a collection of stuff though, isnt it? water, dissolved this and that… i was hoping for more of a discrete thing. what else u got? ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [September 1, 2006, 8:51pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/9 "2006-09-01T20:51:56Z")
Neither hair nor nails are made of dead cells, but rather keratinaceous secretions of living cells. ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [September 1, 2006, 8:59pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/10 "2006-09-01T20:59:00Z")
my vote goes to the eye ball - in particular the vitreous humor which I beleive not to have any live cells in it ---
**Author:** ![KP](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KP](https://boards.straightdope.com/u/KP)\ **Post date:** [September 1, 2006, 9:08pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/11 "2006-09-01T21:08:22Z")
Since it’s a bit unfair to consider hairs/nails collectively, a lens itself (not the overlying membrane) and a vitreous humor would qualify as larger than any one fingernail or hair. Teeth may as well, though I believe there was debate in some circles about the persistence and physiological role of ameloblasts, etc. in adult teeth. It may vary by individual. The osteoclasts/blasts are usually involved in bone surface remodeling and are generally on the external surface, especially in older individuals who have lost many of the cells once contained in their haversian system. Also I believe that not all bones have the Haversian system of canals and lacunae containing live cells. Candidate bones might include flat bones in the skull or pelvis. While some thick parts of the ilium (for example) of a geriatric individual may contain cells, most of the bone (by area) may not. It’s been a long time since histology. My info may be outdated or simply wrong. ---
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [September 2, 2006, 12:14am UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/12 "2006-09-02T00:14:49Z")
[QUOTE=Terminus Est] Neither hair nor nails are made of dead cells, but rather keratinaceous secretions of living cells. [/QUOTE] its true that they are made primarily of keratin, but my understanding was that the part of the hair that is above the skin is made up of dead cells that become filled with keratin. a similar process forms the nails. since the cell remains were essential to the structure and form of the hair, i didnt count hair or nails as a structure that is not composed of cells. ---
**Author:** ![Yeah](https://avatars.discourse-cdn.com/v4/letter/y/dbc845/32.png) [@Yeah](https://boards.straightdope.com/u/Yeah)\ **Post date:** [September 2, 2006, 1:42am UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/13 "2006-09-02T01:42:07Z")
The answer is the vitreous humor. It’s a jelly-like substance that fills most of the eyeball. ---
**Author:** ![gabriela](https://avatars.discourse-cdn.com/v4/letter/g/db5fbb/32.png) [@gabriela](https://boards.straightdope.com/u/gabriela)\ **Post date:** [September 2, 2006, 1:56am UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/14 "2006-09-02T01:56:07Z")
Yeah, but you’re talking healthy people. How about the contents of a fricking HUUUGE sebaceous cyst? Or the goopy mass of fluid and hair and teeth in the center of a teratoma? Or the fluid collection in a VA patient hernia with hydrocele? Or… no better not go there. ---
**Author:** ![Alan\_Smithee](https://avatars.discourse-cdn.com/v4/letter/a/2acd7d/32.png) [@Alan\_Smithee](https://boards.straightdope.com/u/Alan_Smithee)\ **Post date:** [September 2, 2006, 2:55am UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/15 "2006-09-02T02:55:04Z")
Good lord, **gabriela** …the thought that there may be places you’d better not go after making _that_ tour is going to keep me up at night! ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [September 2, 2006, 5:50pm UTC](https://boards.straightdope.com/t/what-is-the-largest-structure-in-the-body-that-is-not-composed-of-cells/371062/16 "2006-09-02T17:50:56Z")
[QUOTE=misterW] its true that they are made primarily of keratin, but my understanding was that the part of the hair that is above the skin is made up of dead cells that become filled with keratin. a similar process forms the nails. since the cell remains were essential to the structure and form of the hair, i didnt count hair or nails as a structure that is not composed of cells. [/QUOTE] On some further research, I find that you are correct.