Digestion by A Morton

Digestion

abglmrtn — 2014-11-02 18:00:09 UTC

is the process where your body breaks down the food that you eat and turns it into the nutrients that you need to help you live.

The first step: the mouth

abglmrtn — 2014-11-02 18:00:48 UTC

The first part of digestion is your mouth. Your mouth breaks down the food in two ways.

First of all, teeth crunch and munch the food into smaller pieces. Different teeth do different things. Your incisors are great at cutting, and getting smaller chunks of food in your mouth than if you just shoved a whole apple in. Your canines are good at tearing. Your molars do a fine job of crunching and grinding, and your wisdom teeth don't really do anything except help the molers.

The other thing in your mouth that breaks down your food is saliva. Saliva contains an enzyme called amylase that breaks down complex carbohydrates or starches (Nelson chap.).

What is an enzyme?

abglmrtn — 2014-11-02 18:01:51 UTC

An enzyme is a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction (Webster's dictionary).

Teeth.. a few interesting facts:

abglmrtn — 2014-11-02 18:02:37 UTC

-teeth are so hard that they are the last parts of your body to decompose (Mom, Oct. 30 2014)

-tonsils are often crowded in the back of your mouth and have to be removed (Dad, Oct. 30 2014)

on the way to the stomach:

abglmrtn — 2014-11-02 18:06:42 UTC

After your mouth has finished it's work, the

food goes down the esophagus with help from squeezing

movements called peristalsis, through the cardiac sphincter

and into your stomach. (Nelson chap. 6)

The second step: the stomach

abglmrtn — 2014-11-02 18:08:21 UTC

The second part of digestion happens in your stomach. The stomach has many ways to break down food. One way it does that is by contracting and churning all the pieces of food.

The stomach also releases an enzyme called pepsin which helps to digest proteins.

Another fluid that is used in the stomach for digestion is called gastric fluid. Gastric fluid contains Hydrochloric Acid which has a pH level of 2-3, so that breaks down food as well. Don't worry though, alkaline mucus stops the stomach walls

from being digested as well.

(Nelson chap. 6)

A few definitions:

abglmrtn — 2014-11-02 18:09:02 UTC

Esophagus: the tube that food goes down into the stomach

Peristalsis: rhythmic squeezing movements that make sure the food goes down the esophagus

Cardiac sphincter: the opening into your stomach that can open and shut like a drawstring

The third step: the small intestine and pancreas

abglmrtn — 2014-11-02 19:19:19 UTC

The third and longest step in digestion is the small intestine. If you were to stretch it out your small intestine would be up to 7 meters long. Because the small intestine is so long, it is divided into sections. The first twenty five to thirty centimeters is called the duodenum. The duodenum is where most of the digestion occurs.

Your pancreas is an organ that comes into play during that phase.

When the hydrochloric acids reach your small intestine, a hormone called prosecretin is released. It then gets turned into secretin and signals the pancreas. When that happens the pancreas releases a fluid containing bicarbonate ions that gets sent to the small intestine and brings the pH level up to around 9. (Nelson chap. 6)

Liver and Gallbladder
Your liver also release stuff into the small intestine. It is a fluid called bile, which helps to digest lipids and is stored in the gallbladder.

Recipe: gastric fluid

abglmrtn — 2014-11-03 02:30:51 UTC

1. Get some mucus (you can find it in the epithelial cells).

2. Add pepsinogen to help digest proteins.

3. Stir thoroughly.

4. Sprinkle in hydrochloric acid (HCL) VERY CAREFULLY!!! IT IS AN ACID!!!

5. Stir carefully. The pepsinogen should react with the HCL and turn into pepsin.

6. Mix in some Assorted Stomach Fluids (TM).

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abglmrtn — 2014-11-03 14:04:56 UTC

What exactly does the pancreas release into the small intestine?

abglmrtn — 2014-11-03 14:05:43 UTC

-trypsinogin is a protein-digesting enzyme
-enterokinase turns inactive trypsinogen into active trypsin (released by small intestine)
-erepsins are enzymes that converts small-chain peptides into amino acids -amylase enzymes continue to break down carbohydrates
-disaccharide enzymes called disaccharidases complete digestion of carbohydrates (released by small intestine)
-lipases are enzymes that break down lipids

The final step: the large intestine

abglmrtn — 2014-11-03 14:15:09 UTC

By the time that the food reaches your large intestine most of the nutrients and chemicals are already absorbed. The food gets stored in the colon, which is a part of the large intestine. While it is stored there, the water is absorbed from the wastes. Once enough waste materials have been collected they are ready to be disposed from your body.

(Nelson chap. 6)

Did you know?

abglmrtn — 2014-11-03 19:57:30 UTC

It is good to eat fibres because they help to pass along any posionus materials. (Nelson chap. 6)

abglmrtn — 2014-11-03 19:59:24 UTC

References:

abglmrtn — 2014-11-03 20:00:09 UTC

Nelson, Biology 11U, Nelson Publishing Company, 2011

"Teeth Names and Locations" areteethbones. November 3 2014 <http://www.areteethbones.co/teeth-names/>

"Esophagus, Trachea, and Aorta" Florida Center for Instructional Technology. November 1 2014 <http://etc.usf.edu/clipart/54100/54187/54187_esophagus.htm>

"Stomach" Houghton Mifflin Harcourt Publishing Company. November 3 2014. <http://www.yourdictionary.com/stomach>

"Digestive System" KidsBiology. November 2 2014 <http://www.kidsbiology.com/human_biology/digestive-system6.php>

"Large Intestine" MedlinePluss. November 2 2014 <http://www.nlm.nih.gov/medlineplus/ency/imagepages/19220.htm>