A eyelash or just eyelash is one of the hairs that grows on the edge of the eyelid. Eyelashes protect the eyes from impurities and perform some of the same functions as mustaches in cats or rats in the sense that they are sensitive to touch, thus providing a warning that objects (such as insects) are near the eye. (which then closes reflexively).
The Ancient Greek word for eyelashes is ???????? (transliterated as blepharon), which is seen as a root in biological terms such as Blephara .
Video Eyelash
Structure
Development
Human embryonic eyelashes develop from the ectoderm between the 22nd and 26th week of pregnancy. The eyelashes require about seven to eight weeks to grow back if pulled out, but a constant withdrawal can cause permanent damage. Their color may differ from hair, although they tend to darken in someone with dark hair and brighter on someone with thin hair. The lashes are not androgenic and therefore unaffected by puberty.
Gland
Eyelash follicles are associated with a number of glands known as the Zeis and Moll glands.
Maps Eyelash
Clinical interests
There are a number of illnesses or disorders involving the lashes:
- Madarosis is the loss of eyelashes.
- Blepharitis is an irritation in the eyelid margin, where the lashes join the eyelid. The eyelids are red and itchy, the skin often becomes scaly, and the eyelashes may fall out.
- Distichiasis is an abnormal growth of eyelashes from certain areas of the eyelid.
- Trichiasis refers to the growing eyelashes
- Eyelashes can become full of parasitic crab lice. External hordeolum, or stye, is purulent inflammation of the infected eyelash follicles and adjacent sebaceous glands (Zeis gland glands) and apocrine glands (moll glands) of the eyelid margins.
- Trichotillomania is a disorder that urges the sufferer to pull hair, eyelashes, etc. Demodex folliculorum (or demodicid) is a mite that lives harmlessly in the lashes and other hair follicles, and about 98% of people have live mites on them. Sometimes they can cause blepharitis.
Eyelash and eyebrow grafting operations can help reconstruct or thicken eyelashes or eyebrow hair.
Society and culture
Cosmetics
Long eyelashes are considered a sign of beauty in many cultures. Thus, some women try to increase the length of their lashes artificially, using eyelash extensions. On the other hand, Hadza women are known to prune their own eyelashes.
Kohl, black putty (usually antimony or lead sulphide), has been used as far as the Bronze Age to darken the edges of the eyelid (only at the bottom of the eyelashes). In Ancient Egypt, it was used also by the rich and the kingdom to beautify their eyes. Modern eye makeup includes mascara, eyeliner, eye putty, and eye shadow to emphasize the eyes. The twentieth century saw the start of a convincing false eyelash, popular in the 1960s. There are also different tools that can be used on eyelashes such as eyelash curler or mascara shield (also called mascara guard or eye makeup).
Permanent eyelash tints and eyelash extensions have also become a popular procedure, even in fairly basic salons. It is also possible to get an eyelash transplant, which is similar in nature to frequent hair transplantation in the head. Because hair is transplanted from hair on the head, new eyelashes will continue to grow like head hair and need to be trimmed regularly.
Latisse was introduced in the first quarter of 2009 by Allergan as the first drug to receive FDA approval for eyelash growth. Latisse is a solution of bimatoprost, an active component of Lumigan glaucoma drug. According to Allergan, eyelash growth is seen within 16 weeks. Growth is reported to occur especially in the upper lashes. Side effects are common and include periorbital fat loss, eye changes and skin hyperpigmentation near the eyes. In addition, the last decade has seen a rapid increase in the development of eyelash conditioners. This conditioner is designed to enhance the appearance of eyelashes. Recently, synthetic human keratinocyte growth factor, naturally present in follicles, has been introduced as an ingredient in eyelash growth products.
Cosmetics companies have recently relied on prostaglandin scientific research and Wnt/b-catenin signal pathways to develop eyelash products. Although bimatoprost is effective in promoting healthy growth of eyelashes and hair adnexa, its effectiveness in patients with eyelash alopecia areata is debatable.
In other animals
Eyelashes, become hairs, are found in mammals. The camel's lashes are very long and thick. Horses and cows have eyelashes as well. Eyelash problem inherited commonly occurs in some dog races and also horses.
Eyelashes are an unusual feature but not known to birds. Hornbills have prominent eyelashes (vestigial feathers without thorns), as do ostriches. Among the reptiles, only Eyelash vipers show a series of modified scales above the eyes that look like eyelashes.
References
External links
- Media related to Eyelashes in Wikimedia Commons
Source of the article : Wikipedia
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