乳房的科學：英語精讀講義

Breasts, they provide nourishment for our babies.

乳房能為我們的寶寶提供營養。

They are one of the few organs not fully developed at birth 文法

乳房是少數幾個在出生時尚未完全發育的器官之一，

and of course they are a major obsession in Western culture.

當然，它們也是西方文化中人們迷戀的一大對象。

Yet there is so much about breasts that isn't discussed or is deemed taboo. 用詞

然而，關於乳房，還有太多內容沒有人討論，或被視為禁忌。

Sorry, taboo.

抱歉，是禁忌。

So what does science say about breasts?

那麼，科學是怎麼解釋乳房的呢？

Forget water into wine, 講解

先別管什麼把水變成酒，

what about blood into milk?

血液變成乳汁又是怎麼回事？

Proteins, sugars and fat are pulled from a mother's blood supply to make milk

蛋白質、糖和脂肪會從母親的血液中提取出來，用來製造乳汁，

and it is this action that has made mammals so successful. 文法

正是這個過程讓哺乳動物如此成功。

Unlike birds or reptiles whose young are dependent on parents to bring them outside food such as insects, 講解

鳥類或爬蟲類的幼體得依賴父母從外面帶回昆蟲等食物，哺乳動物則不同，

mammals from the word mammary access their nutrition at a young age from the secretion of a mother's milk.

「哺乳動物」這個名稱源自乳腺，牠們在年幼時透過母親分泌的乳汁獲取營養。

Breasts come in all shapes and sizes 片語搭配

乳房的形狀和大小各不相同，

and though there is a positive correlation between breast size and weight, 用詞

雖然乳房大小與體重呈正相關，

genes also play a crucial role in the size of boobs. 片語搭配

但基因也在胸部大小上扮演關鍵角色。

50% of the time one breast is larger than the other,

在50％的情況下，一側乳房會比另一側大，

most commonly the left boob known as breast asymmetry.

最常見的是左側較大，這種情況稱為乳房不對稱。

This asymmetry is normal

這種不對稱很正常，

and though scientists aren't entirely clear why, 表達脈絡

雖然科學家還不完全清楚原因，

a possible contributor is the hormonal changes that happen during puberty. 表達脈絡

但青春期發生的荷爾蒙變化可能是成因之一。

On top of this, 表達脈絡

除此之外，

the size of your breasts vary from week to week. 片語搭配

你的乳房大小每週都可能不同。

Yep, the production of estrogen and progesterone throughout the menstrual cycle changes the size of your breasts.

沒錯，整個月經週期中雌激素與黃體素的分泌會改變乳房大小。

Both men and women have nipples and mammary glands

男性和女性都有乳頭與乳腺，

but usually only women have them develop at puberty.

但通常只有女性的乳腺會在青春期發育。

This characteristic is uniquely human as other mammals breasts only enlarge during nursing. 用詞

這項特徵是人類獨有的，因為其他哺乳動物的乳房只會在哺乳期變大。

The ring of pigmented skin surrounding the nipple is called the areola

乳頭周圍那圈帶有色素的皮膚稱為乳暈，

which is covered in little bumps called Montgomery's gland.

上面布滿了稱為蒙哥馬利腺的小凸點。

While lactating, 文法

在哺乳期間，

the glands make oily secretions that keep the nipple lubricated 文法

這些腺體會產生油性分泌物，讓乳頭保持潤滑，

and may also release compounds to make the nipple seem yummy for a baby. 文法

還可能釋放某些化合物，讓寶寶覺得乳頭很「美味」。

The nipple isn't composed of a single orifice 片語搭配

乳頭並非只有一個開口，

but has many tiny holes you cannot see with the naked eye. 片語搭配

而是有許多肉眼看不見的微小孔洞。

After having a baby,

生完寶寶後，

receptors in the nipple detect when the baby begins to suckle

當寶寶開始吸吮時，乳頭內的受器會察覺到，

sending messages to the mother's brain 文法

並向母親的大腦傳送訊號，

causing a release of oxytocin and continued production of prolactin.

促使催產素釋放，並讓泌乳激素持續分泌。

Oxytocin causes the cells that line the mammary glands to contract

催產素會讓構成乳腺內壁的細胞收縮，

and it's also known as the cuddle hormone 用詞

它也被稱為「擁抱荷爾蒙」，

as it enhances the bonding experience between mother and child.

因為它能增進母親與孩子之間的親密連結。

The hormone prolactin is essential in making milk.

泌乳激素是製造乳汁不可或缺的荷爾蒙。

This whole hormonal process can be triggered after only hearing a baby cry 用詞

整個荷爾蒙過程甚至只要聽到嬰兒哭聲就會被觸發，

even if it isn't your baby. 文法

即使哭的不是你的寶寶。

Babies love breasts but so do people. 文法

寶寶喜歡乳房，大人也一樣。

Research has found that people spend more time observing large breasts with a certain hip to width ratio 講解

研究發現，如果一個人的臀部與身體寬度呈特定比例，人們會花更多時間注視其豐滿的乳房，

potentially explaining why breast augmentation surgeries 表達脈絡

這或許能解釋為什麼隆乳手術

are the most prevalent form of plastic surgery

是最常見的整形手術，

with 300,000 surgeries being performed in 2014 in America alone. 文法

光是2014年，美國就進行了30萬例。

However, the same research shows that people prefer breasts of all different shapes and sizes

不過，同一項研究顯示，人們喜歡各種形狀和大小的乳房，

and medium sized breasts were actually rated as statistically most attractive.

而從統計結果來看，中等大小的乳房其實最有吸引力。

Breasts don't only create joy for others 文法

乳房不只會為別人帶來愉悅，

but also for oneself.

也會為自己帶來愉悅。

Studies show that stimulation of nipples enhanced sexual arousal in 82% of women

研究顯示，刺激乳頭能增強82％女性的性興奮，

and 52% of men.

男性中也有52％會如此。

Interestingly, an fMRI scan that mapped the brain's response to clitoral and vaginal self-stimulation

有趣的是，一項fMRI掃描描繪了大腦對陰蒂和陰道自我刺激的反應，

found that the same areas lit up when a woman stimulated her nipples. 片語動詞

結果發現，女性刺激乳頭時，大腦中亮起的是相同區域。

Despite being an amazing source of both nutrition and pleasure, 文法

乳房既是絕佳的營養來源，也能帶來愉悅，

breasts are incredibly vulnerable.

但它們也極其脆弱。

Breast cancer is the most prevalent form of cancer in North America.

乳癌是北美最常見的癌症。

Cells that divide often are at a higher risk of mutation than cells that don't divide 片語搭配

頻繁分裂的細胞比不分裂的細胞更容易發生突變，

and because breasts change and grow over the course of our lives, 片語搭配

而乳房會在我們一生中不斷變化和生長，

these cells are frequently dividing.

所以這些細胞經常分裂。

The hormone estrogen also stimulates breast cell division

雌激素也會刺激乳房細胞分裂，

and there are environmental chemicals found in pesticides, industrial products 文法

而農藥和工業產品中存在一些環境化學物質，

and even our food that mimic estrogen 用詞

甚至我們的食物中也有，它們會模仿雌激素，

and can influence cell growth increasing the risk of breast cancer. 文法

並能影響細胞生長，進而增加罹患乳癌的風險。

Research is discovering new risk factors of breast cancer

研究正陸續發現乳癌的新風險因子，

such as breast density, age of first pregnancy

例如乳房密度、初次懷孕年齡，

and genetic predisposition to breast cancer genes such as BRCA1 and BRCA2. 用詞

以及與BRCA1和BRCA2等乳癌基因有關的遺傳傾向。

This scientific knowledge can help increase prevention.

這些科學知識有助於加強預防。

Although they are vulnerable, they are incredible

乳房雖然脆弱，卻也非同凡響，

and regardless of shapes and sizes, 片語搭配

無論形狀和大小如何，

they are an essential aspect of sustaining human life

它們都是維繫人類生命不可或缺的一環，

and defining us as a species.

也幫助定義了我們這個物種。

Thank you boobs.

謝謝你們，乳房。

Want to learn even more about boobs?

想知道更多關於乳房的知識嗎？

Check out our latest AsapThought video

快去看看我們最新的AsapThought影片，

where we debunk some myths about why women have breasts. 片語搭配

我們在其中破解了一些關於女性為何擁有乳房的迷思。

Click on the screen or use the link in the description

點選畫面，或使用說明欄中的連結，

and subscribe for more weekly science videos.

別忘了訂閱，收看每週更新的更多科學影片。