Beauty is Skin Deep

Beauty is Skin Deep

What is the largest organ in your body? Not your brain, heart or ..would you have guessed skin? Weighing in at ~3.5 kg, with an area of 2 square meters, your skin accounts for 16% of body weight. About 11 miles of blood vessels and 45 miles of nerves travel through the dermis! 

Love the Skin You’re In: Of your 300 million skin cells, roughly 40,000 are shed every minute. This adds up to ~4 kg/year. The good news is that if you don’t like the skin you’re in, you’ll have a new one in 4 weeks. 

Don’t be Squamish: Skin is layered on as polygonal cells tightly connected into a sheet, known as squamous epithelium. The left image shows the typical cobblestone pattern, with nuclei in blue. 

Hair Today, Gone Tomorrow: Mammals have a lot of hair, up to 100,000  follicles on our head. The right image is a section through skin showing hair emerging from follicles in the dermis. The dark blue bulge at the base of the follicle is filled with stem cells. 



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77 Responses to Beauty is Skin Deep

  1. Deeksha Tare says:

    Aha! 🙂

    Thanks for the skinny details Rajini Rao ! Short, crisp, yet so informative! 🙂

  2. Rajini Rao says:

    I hope you guys enjoyed the punny subheadings. They were fun to write 😉

  3. Deeksha Tare says:

    Of course Rajini Rao ! They’re punderful !!!!

  4. That covers it very well, Rajini Rao — and without paying a scalper’s price.

  5. Deeksha Tare says:

    Especially Love the skin you’re in made me laugh so much!! ;D

  6. Rajini Rao says:

    I only skinned the surface of this subject, William McGarvey .

  7. Chad Haney says:

    Also, skin is a complicated route for drug transportation due to the dead layer of skin, fat, and hair follicles.

  8. Rajini Rao says:

    Didn’t you young’uns have a post going on Beauty being Skin Deep, Deeksha Tare ?

  9. Deeksha Tare says:

    Yes indeed Rajini Rao 

    Well in fact I was going to ask you whether that was the inspiration , as soon as I read the first line of your post! 🙂

  10. Rajini Rao says:

    Chad Haney , some chemicals are absorbed amazingly quickly through the skin. You can taste the fishy DMSO (dimethyl sulfoxide) seconds after you get some on your skin.

  11. Rajini Rao says:

    Deeksha Tare , yes it was! 🙂

  12. Chad Haney says:

    Yes, but from a biotransport point of view, predicting the dose necessary for a certain distribution for a population of patients is trickier than most people think.

  13. Rajini Rao says:

    Because of the nerve endings, you mean Roelf Renkema ? All the sensory papillae with ion channels, too. 

  14. Rajini Rao says:

    Chad Haney , not the most reliable delivery path.

  15. Arnav Kalra says:

    Love the post Rajini Rao

    It’s informational and a pleasure to read 🙂

  16. Chad Haney says:

    Exactly my point Rajini Rao 

  17. Rajini Rao says:

    I threw in some nerve endings for you, Arnav Kalra 😉

  18. Awesome..very informative!

    I really wonder how this all fitted inside us so creativity!

  19. Deeksha Tare says:

    Another home work?

    Do you have biology as a subject Arnav Kalra ?

  20. Arnav Kalra says:

    Deeksha Tare Yeah, I study Physics, Chemistry and Biology.

    Will have to ask about the homework.

  21. Rajini Rao says:

    You are welcome, Jitendra Mulay and surya chawla . It’s just basic biology, and I’m glad to share it.

  22. Rajini Rao says:

    Try to stem the flow, Feisal Kamil .

  23. Basic for you Rajini Rao mam’…I never paid attention in bio class..:D

  24. Ohh. Thanks a lot. Next time somebody tells me ‘ you are thick skinned’, I can retort back – ‘SO ARE YOU! ‘

  25. Arnav Kalra says:

    Feisal Kamil I posted a comment. It disappeared.

  26. Arnav Kalra says:

    Jitendra Mulay Even those who do forget half of the stuff they’re taught. Not a big deal.

  27. Rajini Rao says:

    Haha, good one, R Prakash Prakash 🙂 You can also helpfully tell them that their skin is as thick as 4 mm in the soles of their feet. Perhaps a good scrubbing would help them 😉

  28. Good one Rajini Rao  They’ll think of a wire brush.

  29. “40,000 are shed every minute”?

    I think I’m going to vacuum…

  30. Rajini Rao says:

    Food for all the dust mites on your carpets, Jimmy Shepard . Yum.

  31. The subheadings really are great! Those and the titles of course are one of the things that always draws me to your posts. I don’t want to cloud up this thread, but you must explain to me sometime how long it takes you to write something like this up 🙂

  32. Rajini Rao says:

    Thanks, Jimmy Shepard 🙂 I wrote this one in under 10 minutes but I had already seen the images and saved them, and I had already read some interesting info on skin. So I just had to put it together. 

  33. Wow, that from just a creative standpoint is very fast. Now, I require your brain !!!

  34. Rajini Rao says:

    Sure thing, Jimmy Shepard . That’s no skin off my back 😀

  35. Rajini Rao There is now coffee on my monitor from my mouth! Stop it!

  36. Rajini Rao says:

    That’s a pore excuse, Jimmy. Was it such a hair-raising experience? 

  37. Deeksha Tare says:

     Rajini Rao’s pun linary skills go skin deep!

  38. Deeksha Tare says:

    Oops. I guess I’m not making any sense at all…


  39. Rajini Rao says:

    It wasn’t such a hair-brained idea, Deeksha Tare . No need to curl up and dye 🙂

  40. Chad Haney says:

    Keratinly a good attempt Deeks.

  41. Ha haaa!  I got nothing- except I can’t stop laughing! Oh man!!!


  42. Deeksha Tare says:

    LOL!! Then it’s okay I guess Jimmy Shepard !


  43. John Kampsen says:

    Excuse me Rajini Rao , I must go. There’s DNA shed all over my house .

  44. Rajini Rao says:

    John Kampsen , I hate to nit – pick, but don’t listen to those lice. If you must part ways with us, ah fro in the towel!

  45. John Kampsen says:

    Touche, you are on your game today, Rajini Rao 🙂

    Beauty is only skin deep…all 16 pounds of it.

  46. Ginger Nohe says:

    imagen what happens if you dont take care of that

  47. Rajini Rao says:

    Very true, Ginger Leuschner . No wonder there is a multi billion dollar cosmetic industry to “help” 🙂

  48. I’ve long wanted a lampshade made of lab grown leather cultured from my own skin cells just for the gross factor. I wonder why lab grown leather hasn’t been commercialized?

  49. Rajini Rao says:

    Roelf Renkema , Grease is the Word, I agree 🙂

    Frankie Valli – Grease – Movie open (HQ)

  50. Rajini Rao says:

    Richard Healy , is there such a thing? O.o

    Do you have a link? Skin cells can be cultured of course, but I don’t know if a substantive multilayered skin or leather can be grown.

  51. Rajini Rao says:

    Wow, thanks Richard Healy .

  52. Rajini Rao says:

    We may have to wait a while to grow one our size, Richard Healy . “The resulting jacket was tiny, about 2 inches high and 1,4 inches wide and would just fit a mouse.”

  53. Rajini Rao The neat possibility with this is that you could add non-organic materials to the mix to alter the properties. For example maybe you could add silicon carbide to a motorcycle jacket’s elbow patches to better weather a slide across asphalt.

  54. Rajini Rao says:

    Absolutely, very neat. As for the size, if they can grow artificial “meat” in large enough quantities for burgers, then why not jackets.

  55. Rajini Rao They use sheets of organic artificial skin to treat burn victims.

    It’s hard for me to imagine that economic factors are the only thing keeping custom grown jackets off the backs of fashion enthusiasts. I wonder what kind of technical issues are holding things up?

  56. Rajini Rao says:

    It must be the profit margin, as Roelf suggests. “Real” leather is cheap. Same with artificial meat..other than the novelty factor, I wonder if they will sell enough to make a profit.

  57. Rajini Rao says:

    Ah yes, Feisal. But RayFish was fake because we have no way to genetically program different animal patterns on skins at this time. The artificial leather seems to be credible, but still in the artistic/exploratory stage.

    (Enjoy the family!)

  58. Rajini Rao says:

    Oh yes, I didn’t think you did either Feisal Kamil . Just wanted to make the point that the premise for RayFish was way out of the realm of current possibility but that for the vegan leather is not. 

  59. Rajini Rao

    Stupid question- and totally off topic………

    What are those so many stem cells doing there? Is it because cells in the skill divide so much that they need to start often from the stem state thus needing a lot of them? My assumption is that cells divide to form new but you need to start from the stem cell state some proportion of cell divisions. When a cell divides, each division corrupts the DNA a little. So after some iterations the cell line is useless. In that case you have to start from the origin and that is stem cell?

    And, are these stem cells specialized for skin or whatever they are doing there?

  60. Rajini Rao says:

    Vijaya Chaturvedi , so you don’t work on HECAT cells anymore? I used to ask you about them, because of Hailey Hailey disease and calcium pump mutations! If you think of a good paper that I should summarize here, let me know.

  61. Vijaya Chaturvedi Thanks for good reference.

    I will try my best. I suspect I won’t understand much (I am not trained in bio area 🙂 )

  62. Rajini Rao says:

    I was so excited to see my friend, Vijaya, here that I did not see your question, mandar khadilkar 🙂 

    Stem cells at the base of the hair follicle are what make the hair continuously regenerate. Let me look for a Wiki link or something straightforward.

  63. Rajini Rao if you can do some post on research Vijaya is suggesting on skin stem cell, do so please!

    I remember in last part of Bush term, there was a lot of talk on stem cell lines being inadequate and having ban on creating new from embryonic stem cells.

    Then there was research on adult stem cells which are specialized in a particular tissue.

  64. Rajini Rao says:

    mandar khadilkar , this Wiki link on hair follicles is a simple and short read:

    Most of the search results for hair and stem cells focus on baldness 🙂

    Stem cells are a HUGE area of research, with thousands of papers published. This year’s Nobel in Medicine went to stem cell scientists. I’ve posted a couple of times on stem cells, I’ll find you the links.

  65. Rajini Rao says:

    Stem cell posts:

    Also, just search “stem cells” in the Google search bar on G+ and a whole bunch of posts come up.

  66. Rajini Rao I started reading the Wikipedia and the G+ links. My head now is hurting…..

  67. Jim Carver says:

    Good one Rajini Rao didn’t see it at first. Skin is cool. We’re just a bag of water and skin is the best bag ever invented. It gets rid of a lot of the toxins so your liver doesn’t have to.

    Sorry if someone else already said that. I’m just not up to reading the 83 comments at the moment. 🙂 I will later though.

  68. Rajini Rao says:

    Ask, and ye shall receive mandar khadilkar 🙂

    Some bags are reasonably nice looking too, Jim Carver !

  69. The right image shows hair??? guy with such bright green hair must look like a cartoon 😉

  70. Rajini Rao says:

    Mark Bruce , look to your maternal grandfather and not your father for the fate of your hair follicles 😉

    Male  pattern baldness is X-linked and if you have it, your mother is the carrier, not your father.

  71. Rajini Rao says:

    Here is the story that Vijaya Chaturvedi was telling us about..a hair loss gene for alopecia:

  72. Great post, Rajini Rao!   As a hair transplant surgeon, it’s a subject near and dear!  Medications/Lasers we prescribe for hair loss, nutrition, genetic testing we do, stemcell-based therapies… it’s all relevant to your brief post and the comments! All with a nice splash of humor.  A +1 & share for sure! 

  73. Susan LaDuke says:

    If only I COULD replace the skin I’m in…..

    That would be lifesaving for someone like myself with Atypical Nevus Syndrome. I dread the dermatologist and have been negligent in scheduling follow up appointments. Family history is awful; father, mother, brother with melanoma (dad deceased after digilent f/u, but went metastatic to brain, lymph and liver) and I’ve had pre lesions myself. This is such an issue with me and I strongly believe that Tanning salons (aka cancer beds) should be outlawed; they are as evil as smoking and completely unregulated.

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