+ الرد على الموضوع
النتائج 1 إلى 2 من 2
  1. #1
    Junior Member
    تاريخ التسجيل
    Nov 2016
    المشاركات
    3

    Ultraviolet radiation on hair fall by Aisha Mansur Kurfi 100597

    Name: Aisha Mansur Kurfi
    ID: 100597
    The video was made by me, it explains everything below with visuals foe more understanding


    ULTRAVIOLET RADIATION ON HAIR FALL

    • Ultraviolet (UV) radiation is an electromagnetic ray which lies between X-rays and visible light in the electromagnetic spectrum, with wave ranged from 100-400 nm.
    • The natural source of UVR is the sun, which emits a broad spectrum of UV
      including UVA, UVB, & UVC. Both UVA & UVB reach the earth from the sun;
      UVC is filtered out by the ozone layer.
    • UV is produced artificially for therapeutic purposes by the passage of electric
      current through ionized vapor. It is produced by mercury vapor lamps.
    • All UV lamps also produce visible light IRR.
    • The depth of penetration of the skin by UV radiation of different wavelengths: UVB
      mainly affects the epidermis, while UVA penetrates deeper into the dermis.


    Physiological effects of UVR
    The penetration of UV is 2mm to the dermis & epidermis, so the effect is local but if large area treated with high dose the effect will be general.


    Local Effects:
    1. Erythema: redness of skin by increased blood flow to capillaries
    2. pigmentation of skin due to increased deposition of melanin
    3. hyperplasia or epidermal thickening
    4. peeling of the skin
    5. antibiotic effect




    General Effects
    1. production of vitamin d by absorption of UVB by skin
    2. aging of skin
    3. cancer due to effect on DNA and cell replication
    4. causes hair fall and more
    UVR ON HAIR FALL
    Hair is made from keratin the same protein that makes our nails and skin
    its one of the toughest materials in our body. it protects the scalp from outside materials and UV radiation.above our skin , the hair shaft has no living cells . UV light causes the hair shaft to lighten and become brittle causing it to break and fall . deep inside the hair follicle, the base of the hair is alive. Below the surface,UV radiation affects cell DNA and induces inflammatory factors in cells causing hair damage




    Blood vessels transport nutrients so new hairs can form, normally each hair grows for between two and eight years before it falls out and is replaced by another one


    Our chromosomes are inside every cell of our body, these hold thousand of genes that tell our bodies how to develop a function, scientist have now discovered many genes that are linked to baldness. But thats not what we’re going to talk about today.
    The oxidative damage caused by UV light alters the amino acids (especially tryptophan, cystine, tyrosine, and histidine) in hair shaft proteins, degrades moisturizing lipids, and breaks down the melanin pigments that help protect hair from UV light


    Testosterone is an androgen which is a sex hormone that both men and women have even though woman have it in low quantity, as it enters to scalp, it is converted to the chemical dihydrotestosterone which is mostly responsible for hair fall.
    As UV light from the sun or machines emitting UV light touches the scalp, It increases the movement of DHT to hair receptors. DHT then sticks to the hair receptors and the UV induces inflammation causing DHT to block the receptors. As more UV radiation hits the scalp, the hair follicle receptors are blocked and don’t get enough nutrients causing them to shrink and become smaller and more brittle causing them to fall.






    Protection of hair from UV radiation
    Naturally present Protection
    melanin pigments
    especially those in dark hair offer some antioxidant protection against UV damage by helping prevent UV breakage of the disulfide
    bonds in hair Protein. Not only does hair turn white or grey as a consequence of this, it also loses the protective benefits of melanin




    Artificial protection
    :Protection from UV-Induced Hair Damage
    Hair sunscreens offer some protection from UV damage, but it is limited bytwo important factors, even with liberal application of the product. These factors are:
    1. uneven coverage
    2. poor adherence to hair cuticle.
    . And the aesthetic effect is often less than appealing, with limp and greasy hair that only makes thinning hair look worse


    Another way to protect hair is from the inside out
    Hair dyes, which penetrate through to the cortex, can offer the same antioxidant protection of lost melanin pigments


    Foods (e.g., coffee, tea, grains, and meats) rich in vitamin B3 (nicotinamide or niacin) may also offer protection from UV radiation DNA damage and
    .depletion of cellular energy



  2. #2
    Junior Member
    تاريخ التسجيل
    Nov 2016
    المشاركات
    3
    The video is not uploading, it keeps refreshing and stopping. And it is very important.

 

 

ضوابط المشاركة

  • لا تستطيع إضافة مواضيع جديدة
  • لا تستطيع الرد على المواضيع
  • لا تستطيع إرفاق ملفات
  • لا تستطيع تعديل مشاركاتك
Powered by vBulletin® Version 4.1.5
Copyright © 2018 vBulletin Solutions, Inc. All rights reserved.
Search Engine Optimization by vBSEO 3.6.0
المنتدى من تصميم وتطوير إتقان لتصميم مواقع الانترنت
Tabs System by vbSoporte - vBulletin en Espa?ol
الساعة الآن 03:04 PM بتوقيت الرياض