Why do we have split ends?
為什麼我們的頭髮會分叉?
Because the world is coming to an end.
因為世界末日到了。
No.
不。
Split ends or trichoptilosis is a type of hair damage in which our hair strand or hair shaft splits into two or more branches.
發梢分叉或毛髮縱裂症是一種頭髮損傷， 在這種情況下，我們的髮根或毛幹分裂成兩個或更多分支。
It mostly occurs at the end of the shaft.
分叉大多出現在發梢。
However you can have split ends anywhere along the entire shaft.
然而，頭髮的任何一段都可能分叉。
Now our hair consists of 3 concentric layers.
現在，我們的頭髮由3個同心層組成。
The outermost tough layer is called cuticle.
最外層的硬層叫做角質層。
The middle layer is called cortex and the innermost layer is called medulla. .
中間的一層叫皮層，最裡面的一層叫髓質。
Split ends occur when the cuticle gets ripped off or damaged.
角質層被撕開或損壞時，就會出現分叉。
Now as there is no longer any tough structure to hold the hair together.
現在，因為沒有任何堅硬的結構把頭髮連接在一起。
Cracks begin to develop in the inner layers thus giving rise to split ends.
內層開始出現裂縫，從而導致分叉。
Now there are many factors that can cause split ends.
很多因素會導致發梢分叉。
For example, excessive sun exposure, improper brushing or detangling, excessive blow, drying, coloring, etc.
例如，過度暴露在陽光下，不適當的梳頭髮或編發，過度吹打，烘乾，染色等。
Topic: Nerves
話題:神經
Why don't we feel pain when we cut our hair?
為什麼我們剪頭髮的時候感覺不到疼痛呢?
Well because if it would then we would have got angry on our hair dressers.
因為如果疼痛的話，我們就會對理髮師不滿。
Oh you are just impossible.
哦，這不可能。
Wait I will explain it to you.
等一下，我會給你解釋。
Inside our body there is a network of nerves.
我們體內有神經網絡。
These nerves help us to sense our surroundings and feel pain, touch, etc by sending messages to the brain.
通過向大腦發送信息，這些神經幫助我們感知周圍環境，感受疼痛、獲得觸覺等。
So do the nerves of my hair not know how to send a message?
所以，我的頭髮神經不知道如何發送信息嗎?
No. Generally the part of our hair above the skin is made up of dead cells.
不。一般來說，我們皮膚以上的毛髮由死細胞組成。
It does not have any nerves.
它們沒有任何神經。
Hence when we cut our hair due to the absence of nerves our brain does not receive any messages of pain.
因此，當我們剪頭髮時，因為沒有神經,我們的大腦不會接收到任何疼痛的信息。
As a result we don't feel any pain.
因此，我們感覺不到任何疼痛。
Topic: Dandruff
話題:頭皮屑
Why do we get dandruff?
為什麼我們會有頭皮屑?
Tearing of pages. No. Dandruff is a condition in which our scalp Sheds skin cells in the form of white flakes.
像是撕碎的紙屑。不。頭皮屑是頭皮上脫落的皮膚細胞，通常是白色薄片。
A yeast called Malassezia globosa Is one of the mostly accepted reasons for causing dandruff.
引起頭皮屑的主要原因之一是一種酵母,名為馬拉色菌。
What a classy name it has.
名字真好聽。
Indeed. Malassezia globosa is naturally present on our scalp.
的確，馬拉色菌自然地存在於我們的頭皮。
It feeds on sebum and releases oleic acid.
以皮脂為食，釋放油酸。
Now some people are sensitive to this oleic acid.
有些人對油酸很敏感。
When it penetrates into the upper layers of their skin it causes inflammation.
當油酸滲透到皮膚上層時，就會引起炎症。
Hence in response to this inflammation their skin sheds a large number of skin cells at a higher rate.
因此，患上這種炎症後，皮膚便以更快的速度脫落大量皮膚細胞。
These cells then join together forming white flakes thus causing dandruff.
這些細胞結合在一起形成白色薄片，從而產生頭皮屑。
Topic: Human hair. Why do we get white hair?
話題:人類的頭髮。為什麼我們會有白頭髮?
Because we cannot get blue hair.
因為我們沒有藍色頭髮。
No. Our hair is basically made up of keratin a colorless protein.
不，我們的頭髮基本.上是由角蛋白(一種無色蛋白質)組成。
Hence before our hair comes out of the skin it is almost white.
因此，頭髮在從皮膚裡長出之前，幾乎是白色的。
How's that possible? I had black hair during childhood.
那怎麼可能?童年時我的頭髮是黑色的。
Don't worry I will explain!
別擔心，我會解釋!
Our hair grows from hair follicles.
我們的頭髮從毛囊中長出。
A hair follicle contains melanocytes which produce melanin.
毛囊有分泌黑色素的黑色素細胞。
Melanin is injected in the keratin cells during the growth of our hair.
頭發生長過程中，黑色素被注入角蛋白細胞。
This melanin gives color to our hair.
這種黑色素讓頭髮有了顏色。
Now the color of our hair is dependent on the type of melanin injected.
我們頭髮的顏色取決於注入的黑色素的類型。
Eumelanin makes our hair black or brown while pheomelanin makes our hair red or blond.
真黑素使我們的頭髮變成黑色或棕色，褐黑素讓我們的頭髮變成紅色或金色。
However as we grow old the melanocytes decrease the production of melanin.
然而，隨著我們變老，黑色素細胞會減少分泌黑色素。
Thus less melanin is injected in hair causing them to eventually turn white.
因此，注入頭髮的黑色素減少，最終導致頭髮變白。