# Blood donation screening question: What is a "mucous membrane"?

**URL:** <https://boards.straightdope.com/t/blood-donation-screening-question-what-is-a-mucous-membrane/654956>\
**Category:** Factual Questions\
**Created:** [April 5, 2013, 9:35pm UTC](https://boards.straightdope.com/t/blood-donation-screening-question-what-is-a-mucous-membrane/654956 "2013-04-05T21:35:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\
**Post date:** [April 5, 2013, 9:35pm UTC](https://boards.straightdope.com/t/blood-donation-screening-question-what-is-a-mucous-membrane/654956/1 "2013-04-05T21:35:21Z")

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I gave blood yesterday and one of the screening questions asked was something like “In the past 12 months have you come into contact with someone else’s blood?” (as seen in [page 9 of this example screening](https://docs.google.com/viewer?a=v&q=cache:eGRD4UIS1qQJ:www.aabb.org/resources/donation/questionnaires/Documents/dhqhpccord/DHQ-HPC-cord-flow-chartsv1.doc+&hl=en&gl=us&pid=bl&srcid=ADGEESg2dL4bZaRyFl1vcN7vNV0aB17Q_EhB8UqDYTvHgA07N7pUQ2c4W55RMUkzJRsPj6tnN01k9C5-meFFhkeHdo0FuT24L4VWDn_uCuuks5qxhdqAz5CHPw9h_ekfKFqFAtQts_NM&sig=AHIEtbRLu1NujL2Ib6pQIZJpV8cj4SHuxQ)). The followup question was: “Was that contact with an open wound, non-intact skin or mucous membrane?”

I was wondering what exactly qualifies as a “mucous membrane”. I guess if somebody bled on my intact skin, that’s fine, but not my eyes? What about:

- Through the mouth
- Ears
- Nose
- Belly button
- Penis (like if the woman was on her period)
- Anus

?

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [April 5, 2013, 9:46pm UTC](https://boards.straightdope.com/t/blood-donation-screening-question-what-is-a-mucous-membrane/654956/2 "2013-04-05T21:46:05Z")

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Ears & Belly Button aren’t, all the rest are.

Just think about any part of your body that’s “wet.”

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**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\
**Post date:** [April 5, 2013, 9:56pm UTC](https://boards.straightdope.com/t/blood-donation-screening-question-what-is-a-mucous-membrane/654956/3 "2013-04-05T21:56:05Z")

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> [@Reply](#):
>
> I  
> I was wondering what exactly qualifies as a “mucous membrane”. I guess if somebody bled on my intact skin, that’s fine, but not my eyes? What about:
> 
> - Through the mouth
> - Ears
> - Nose
> - Belly button
> - Penis (like if the woman was on her period)
> - Anus
> 
> ?

> **[Mucous membrane](https://en.wikipedia.org/wiki/Mucous_membrane)**
>
> A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is mostly of endodermal origin and is continuous with the skin at body openings such as the eyes, eyelids, ears, inside the nose, inside the mouth, lips, the genital areas, the urethral opening and the anus. Some mucous membranes secrete mucus, a thick prote...

Includes the lining of the “insides” of the body cavities, including respiratory (nasal, pharyngeal) and digestive (which in turn includes the mouth and the inside of the anus); the lining of the eyelids and lachrymals; the glans of the penis, the “inside” fold of the foreskin, and the urethra.  
The navel is not mucosa, it’s a healed scar. The ear canal is epidermal, it evolved from a structure where the eardrum was on the surface and in mammals it moved inward.