Name: 飢餓的微生物組。消化系統 (Hungry Microbiome: The Digestive System)
Uploaded: 2021-01-14T05:34:15.000Z
Duration: 14 min 58 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

(Narrator) This is Armando. This video was created as part of the Hungry Microbiome Project,

The digestive system is responsible for the breakdown,

The digestive tract, also known as the alimentary canal,

is the pathway where food travels through after being ingested.

The digestive tract consists of the mouth,

Therefore we can refer to the digestive tract

as a long tube that runs from the mouth to the rectum.

Food enters the mouth and leaves through the rectum.

But there are also other organs called accessory organs

that play fundamental roles in digestion.

These organs include the salivary glands,

the liver, gall bladder and the pancreas.

Without the proper function of these accessory organs

food will not be digested properly, and consequently

gastrointestinal diseases, such as malnutrition.

So looking at a general overview of the digestive system,

food can be grouped into three main categories

carbohydrates, such as bread; protein, such as meat;

The food will be digested by the digestive system

where it will be then delivered to body tissues as energy,

all share three similar anatomical properties.

Here I am drawing a diagrammatical cross section

The digestive tract have three main layers.

The lumen is the inside space of the digestive tract.

and also protects the lining of the digestive tract.

Some of these cells are what produce and secrete mucus.

The third layer is the smooth muscle layer, the outer layer,

to move through the digestive tract after being ingested.

Now that we have a better feel for the digestive system,

let us look at each of the organs of the digestive system

and what they do in relation to foods being consumed.

the process called mastication occurs, which is essentially chewing.

Food will be broken down mechanically by the mouth,

The tongue plays a role in tasting the food,

while the salivary glands within the oral cavity secrete saliva,

the sublingual, meaning below the tongue,

parotid, and submandibular, which means below the mandible.

The salivary glands also secrete an enzyme called amylase,

which will initiate carbohydrate digestion.

in a partially digested form it is swallowed,

The food is actually now referred to as a bolus.

is a mass of food that has been chewed up.

The bolus will travel through the oesophagus

Now peristalsis is the involuntary contraction of the smooth muscles

And so the bolus will eventually enter the stomach.

The stomach will temporarily store and churn the bolus.

The stomach cells also secrete chemicals and enzymes,

such as hydrochloric acid, that helps break down the food,

kill bacteria, and stimulate enzyme secretions.

that helps protect the lining of the stomach,

as well as pepsin that begins protein digestion.

The vigorous contraction of stomach muscles

which is then slowly released into the small intestine.

is the barrier between the stomach and the small intestine.

During digestion the pylorus sphincter opens in phases,

字幕列表影片播放

飢餓的微生物組。消化系統 (Hungry Microbiome: The Digestive System)

layer

system

absorb

bacteria