Introduction to GIT System

Where  the food will go after eating?

Digestion is the breakdown of food into smaller components that can be more easily absorbed and assimilated by the body. In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication, and the wetting contact of saliva.  After undergoing mastication and starch digestion, the food called a bolus will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion.

After some time, the resulting thick liquid is called chyme and enters the duodenum where it mixes with digestive enzymes from the pancreas, and then passes through the small intestine, in which digestion continues. When the chyme is fully digested, it is absorbed into the blood. Water and minerals are reabsorbed back into the blood in the colon (large intestine) where the pH is slightly acidic. Some vitamins, such as biotin and vitamin K produced by bacteria in the colon are also absorbed into the blood in the colon. Waste material is eliminated from the rectum during defecation. 

Peristalsis

What is Peristalsis?

A wave-like muscular contractions of the alimentary canal or other tubular structures by which contents are forced onward toward the opening.

Where can Peristalsis occur?

-          Oesophagus

-          Small Intestine

-          Large Intestine

How Peristalsis occur in Esophagus?

After food is chewed into a bolus, it is swallowed and moved through the esophagus. Smooth muscles contract behind the bolus to prevent it from being squeezed back into the mouth. Then rhythmic, unidirectional waves of contractions will work to rapidly force the food into the stomach. This process works in one direction only and its sole purpose is to move food from the mouth into the stomach.

Types of Peristalsis occur in Esophagus?

-          Primary Peristaltic wave

-          Secondary Peristaltic wave

What is the Primary peristaltic wave?

It occurs when the bolus enters the esophagus during swallowing. The primary peristaltic wave forces the bolus down the esophagus and into the stomach in a wave lasting about 8–9 seconds. The wave travels down to the stomach even if the bolus of food descends at a greater rate than the wave itself, and will continue even if for some reason the bolus gets stuck further up the esophagus.

What is the Secondary peristaltic wave?

In the event that the bolus gets stuck or moves slower than the primary peristaltic wave (as can happen when it is poorly lubricated), stretch receptors in the esophageal lining are stimulated and a local reflex response causes a secondary peristaltic wave around the bolus, forcing it further down the esophagus, and these secondary waves will continue indefinitely until the bolus enters the stomach. The process of peristalsis is controlled by medulla oblongata.

  

WHAT THE LIVER DOES?

●      It regulates the composition of blood, including the amounts of sugar (glucose), protein, and fat that enter the bloodstream.

●      It removes bilirubin, ammonia, and other toxins from the blood.

●      It processes most of the nutrients absorbed by the intestines during digestion and converts those nutrients into forms that can be used by the body.

●      The liver also stores some nutrients, such as vitamin A, iron, and other minerals.

●      It produces cholesterol and certain important proteins, such as albumin.

●      It produces clotting factors, chemicals needed to help blood clot.

●      It breaks down (metabolizes) alcohol and many drugs.

WHAT THE GALL BLADDER DOES?

❖    Store bile and release the bile to the duodenum for digestion of fats.

WHAT THE PANCREAS DOES?

I keep thinking, where was the food I just ate had gone missing in my stomach (except the stool)?

Our foods participate in a process called absorption. The thinnest product of digestion will be absorbed by villi (structure in small intestine) into either blood vessel or lymph duct depend on the type of product.

There is also a process called reabsorption. This process only applied on water, electrolyte and bile acid.

#did you know, normally, we do not feel the intestine's movements, but, if we eat too much, we can experience a painful sensation and, if we get a food poisoning, we will suffer of violent spasms and pain.

Why do we still need to defecate if the food is important to our body? Was that not a waste?

We really need the process called defecation after all. Why? It is because not everything we consume is going to be absorbed and some of them even can endanger to our body. Our feces will be damped first at rectum before defecating.

# actually, it’s important to educate ourselves about defecation so that we can acquired some knowledge on  what’s weird, what’s normal, what’s healthy, what’s not. That’s because your bathroom behavior can be an important clue to your overall health. You can reveal signs of infections, digestive problems, and even early signs of cancer.