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The Digestive System

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Alastair Hoskinson

on 20 November 2013

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Transcript of The Digestive System

The Digestive System
& A Balanced Diet

The mouth is the first part of the digestive system. Two types of digestion happen here:

1. Chemical Digestion
2. Physical Digestion

You probably never thought about it but physical digestion is happening all the time when we eat. As we know for nutrients to be absorbed into the blood stream, they have to be
micro. Your teeth chew the food that you eat so it can flow down the esophagus smoothly and be digested.

Chemical digestion in the mouth happens through the enzyme, amylase that is found in your saliva. Amylase breaks down starch molecules into tiny glucose molecules. It is produced in the salivary glands. This process is called "Indigestion".
Salivary Gland
The salivary gland is responsible for producing amylase (in the form of saliva) which is send to the mouth for chemical digestion through salivary ducts. Saliva is important because it is also used to lubricate the esophagus.
Although the esophagus doesn't complete any digestion itself, it is a vital part of the system. The esophagus is the transporter of food from the mouth to the stomach. The muscles of the esophagus contract to send the food down the 8 inch tube. These contractions are called peristaltic movements. This is a step of the digestive process that is completed physically.
A Balanced Meal
As you can see from this pie chart there are 3 main macro-nutrients: protein, fat and carbohydrates. It is essential to have the right amounts of each of these nutrients in your meals. Ideally the split should be 50% carbohydrates, 25% fat and 25% protein.
I think this meal is great for fulfilling the bodies needs because it contains the about the right amounts of macro-nutrients and has a variety of the food groups. It also contains 831 calories, which is ideal for one meal in the day. To make this meal healthier, I could possibly balance the macro-nutrients in the food out, so that the split is a perfect, 50 - 25 - 25. Now let me tell you what I am getting out of each of these foods.

Before we get started it is important to know what is essential for a healthy meal. There are two main things to look for:

- calories between 750 & 1000 for one meal
- a balance of important macro-nutrients

For more check out this cool song about nutrition:

Tropical Fruit Smoothie:

- provides good amounts of carbohydrates
- a good source of vitamins
- provides a good 13.5 grams of protein
Pork Strips:

- balances out the meal with sufficient fat
- little carbohydrates (improving the balance of the meal

Soy Protein Concentrate:

- high in protein
- low in fat
Great! I have sufficient macro-nutrients! But where are they going? Well, different parts of your body digest different macro-nutrients and turn them into micro-nutrients. They do this through enzymes. Enzymes are responsible for turning macro-nutrients into the things that the body needs. Let me show you the parts of the digestive system responsible for breaking down macro-nutrients.
The carbohydrate starch is broken down inside the mouth by an enzyme called "Amylase". Amylase is produced inside the salivary gland and turns starch into tiny glucose molecules for the body to absorb.

Protein is broken down inside the stomach. First, hydrochloric acid converts pepsinogen into its active form, the enzyme pepsin. The product is essential amino acids: energy.

Fat is digested in the small intestine by an enzyme called lipase with the help of bile. The bile isolates the fat molecules for the lipase to break it down further into acidic fatty acids. Fatty acids provide essential omega 3 oils, important for the maintenance of the body. Moving onto the digestive system....
The salivary gland produces amylase. As mentioned earlier amylase is the enzyme responsible for the digestion of starch. When the food is swallowed it travels down a long tube. Next to the esophagus is the larynx (or better known as your wind pipe) which used to help speech. It is important that no food enters the larynx or you could become very sick, which is why there is the epiglottis; responsible for separating the two.
The Stomach
The stomach is a very important part of the digestive system. It is responsible for turning the food that comes from the esophagus into chyme, partially digested food. This is done by pepsin with the help of hydrochloric acid. Inside the stomach, protein is digested by the enzyme protease and is turned into amino acids: essential energy. But none of this would be possible without gastric juices. Due to protease being a very strong acid at a ph of 2, gastric acids help neutralize the chyme, so that the stomach isn't damaged in any way. The digestion process in the stomach can take from 2 to 3 hours.
Gall Bladder
The gall bladder is used to store excess bile that was wasted in the digestion of food in the small intestines so that it can be reused again on more meals.
The Liver
The liver is responsible for producing bile - essential for digestion of food in the small intestines. This is also the place where cholesterol is processed. Bile helps isolate fat molecules so that they can be digested by the enzyme lipase.
The Pancreas
The pancreas is another organ that is responsible for storing and secreting juices produced inside the liver.
The Small Intestines
The small intestines are probably the most important part of the whole digestive system. This digestion process takes the longest (4 hours) and digests the most food. This 7 metre long tube is responsible for digesting fat molecules using the enzyme lipase and bile, by turning them into fatty acids (omega 3's & 6's) essential for energy and the maintenance of our bodies. Sufficient fatty acids are also proven to prevent some chronic diseases. This is the stage where all the digested food is ready to be passed on through a sponge like organ called the "villi". This process is called "absorption".
The Large Intestines
The undigested waste and water that remains, then travels through the large intestines. Here all the water is removed and all the waste is combined into compact "packages", formally called feces. If you have been having a rough time on the toilet lately, it is probably because you have not been getting enough fiber. Sufficient fiber ensures that feces are processed for the right amount of time so that they are not too hard, but not too soft. Hard feces that are aren't eliminated with ease are a result of constipation. Vice versa, if you digest something that the body doesn't need, it shoots it out of the large intestines quickly, causing feces to be soft. This is called diarrhea.
Here is a Youtube video showing the in journey into stomach.
The rectum is the final piece of the large intestine meaning "straight intestine" in latin. It is responsible for the storage of feces that have been processed earlier in the large intestines. No digestion happens here. It is approximately 12 cm long. This is the second last step to the digestive process before waste is sent to the anus for elimination.
This is the final step of the digestive system where feces are eliminated (pooped out).
So there you have it, literally!
By Alastair Hoskinson
Thanks For Watching!
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