DIGESTIVE    SYSTEM

Parts of the Digestive System.

It is a long tube from the mouth to the anus, in the middle there are many important parts and organs:

Mouth ( tongue, teeth and salivary glands ), Pharynx, Esophagus, Stomach, Liver and gallbladder, Pancreas, Small intestine ( duodenum, jejunum and lleum ), Large intestine ( cecum, appendix, ascending colon, transverse colon and descending colon ), Rectum and Anus.

Main Functions.

We eat food ( lipids, fats, meat ), mainly it is digested in the stomach and small intestine. Our digestive system obtains energy for life. Also we produce digestive enzymes. These ones are released by our body. They help us making the digestion of food, for example amylase, lipase, protease ...

Enzyme	Reaction catalysed
Carbohydrase (eg amylase)	Starch → sugars
Protease	Protein → amino acids
Lipase	Fat → fatty acids + glycerol

Different enzymes are produced in different parts of the digestive system.

Enzyme	Where produced
Carbohydrase (eg amylase)	Salivary glands, pancreas, small intestine
Protease	Stomach, pancreas, small intestine
Lipase	Pancreas, small intestine

How is the digestion made?

Mouth. Food is chewed in smaller pieces with teeth and it is mixed with saliva from salivary glands. They produce amylase this enzyme is essential for the digestion of carbohydrates  ( bread, rice, pasta … ) into sugars, glucouse

Esophagus. We swallow the food through the esophagus to the stomach, it is a muscular tube.

Stomach. The shape is like the letter J. It is a food storage, here, food is mixed with gastric juices. Stomach produces chloridic acid and fat, in this organ are digested. Food is passed  along the small intestine.

   
Liver and Bile. The liver produces bile which is stored is the gallbladder. Bile reachs the small intestine (duodenum part) where it dissolves fat  ( oil, butter, bacon ….   )

Pancreas. It produces three enzymes : protease, lipase, carbohydrase that breaks down fats, proteins and carbohydrates.

Small intestine. ( Six meters long ). It works with help from the pancreas, liver and gallbladder to break down down  the food even more, all the sugars, fats, proteins, vitamins and minerals can pass through the intestine into the blood. The inner surface of the small intestine is covered with villi, this increases the surface area to absorb the food. The blood transports and moves the nutrients and these reach the different parts of our body.

Large intestine. Water is absorbed.                                             

                                                           

  Rectum. Waste are stored here.

 Anus. Waste leave the body through the anus.

Interaction with other systems.

Muscular system. The tongue and facial muscles help us for chew the food. 

 

This image shows the muscle contractions into the esophagus. Peristalsis helps moving the bolus ( mixed food and saliva ) down the esophaugus to the stomach.

The next image shows three types of muscle layers in the stomach. This muscles interview in the digestion. We shallow and digest because we have muscles in the digestive tract.

Circulatory system.

We eat, we need energy for life. Digestive system breaks down food into nutrients and waste. Nutrients are transported for the smallest blood vessels ( capillaries ). Exchange of nutrients are made in the villi, small intestine.

Nervous  system. 

                                   

There is a second brain in our gut. You have feeling butterflies in the stomach, when you are excited. It is about 100 millions of nerves found of the gastrointestinal tract, pancreas and gallbladder. It is ENS ( enteric nervous system ). The ENS doesn’t speak and think but, it reports to the brain about many mechanical and chemical reactions in the body. In fact 95% of the body’s serotonin can be found in the gut.

Serotonin is the happiness hormone, if you feel good the level of serotonin is high. The gastrointestinal tract is sensitive to emotions, stress, anxiety and depression.

Illnesses of the digestive system.

Celiac disease.

It is caused by a permanent intolerance for gluten, a protein found in wheat, rye and barley. The body´s immune system reacts against the protein gluten. You can find wheat flour in many food: bread, soap, pasta, pizza, cookies, cakes…

Cancer colon.

It is a disease of the large intestine. Malignant cells ( cancer ) are formed in the tissues of the colon ( part of the body´s digestive system ). Signs include blood in the stool or a change in our intestine habits.

Thank you for your attention !!!