What are the sizes of the cells that make up human hair?
The question is in the title, but I'll explain why the question arose. I'm curious about the rates that various cells in the body divide, and have found various information relating to this, but nowhere can I find how often the cells divide in hair follicles (only that hair grows about 1 cm per 28 days, and that hair matrix epithelial cells divide very rapidly, which results in chemo patients' hair falling out). I figure that I can calculate a back-of-the envelope answer if I know the average size of hair cells. For example if they are 10 $\\mu$m, and hair grows 1 cm per 28 days, then I would estimate that the relevant cell turnover time in the follicle is on the order of 1.5 per hour, assuming that the cellular division leading to the outward growth of the hair proceeds in a serial fashion. This sounds like a roughly plausible estimate, since it is significantly faster than the turnover of other cells in the human body with a high turnover (like stomach or blood neutrophils) which have a turnover of a few days.In any case I would appreciate any insight, whether the size of hair follicle matrix epithelial cells or the cellular turnover rate in the follicle during the anagen phase.
hair Is made of of a protein called keratin. I am not sure the size of the protein other than it is 520 amino acids long. Dermal cells that are located in the bulb and help produce keratin are 8-21 microns in diameter. Which kind of leaves you with a wide range to calculate with. If you have any further questions or would like to schedule a session please feel free to send me a message. I am more than happy to help!
