Phases of Gastric Secretion

The gastrointestinal system of the physical body comprises a gaggle of organs working together to convert food into energy for the body. Anatomically, the gastrointestinal system is formed from the alimentary canal , alongside accessory organs like the liver, pancreas and gallbladder. The hollow organs that structure the alimentary canal (GI tract) include the mouth, stomach, oesophagus, intestine and enormous intestine that contains the rectum and anus.

The digestion process involves the alimentary tract alongside various accessory organs and organ systems. Due to the monogastric nature of the human body, the process becomes very easy. This means that we've a one-chambered stomach, unlike other animals like cows, which have four chambers. A combination of nerves, bacteria, hormones, blood and other organs of the gastrointestinal system completes the task of digestion. 

Gastrointestinal Tract Anatomy

The alimentary tract in humans begins at the mouth, continuing through the esophagus, stomach, and thus the tiny and massive intestines. The alimentary canal is about 9 meters long. There are supporting organs like the liver which plays an important role by secreting enzymes that are necessary for the digestion of food.

The GI tract of the human being can be bifurcated into 2 halves - 

• Upper GI tract

• Lower GI tract

Upper Gastrointestinal Tract

The upper GI consists of the following organs:

Mouth

It includes the teeth, tongue, and buccal mucous membranes containing the ends of the salivary glands that continue with the taste bud , floor of the mouth, and underside of the tongue. Mouth functions by chewing the food, constantly by the muscular action of the tongue, cheeks, teeth through the lower and upper jawbone .

Pharynx

The pharynx is enclosed within the neck and throat which functions as a part of both the gastrointestinal system and therefore the systema respiratorium . The food is protected from entering the lungs and trachea.  

Esophagus

It is a muscular tube-like structure which carries food to the stomach as its function. After the food reaches the esophagus from the mouth, the swallowing becomes involuntary and the esophagus takes the charge.

Stomach

Stomach may be a place where most of the digestion occurs. The stomach is a J-shaped bag-like organ that helps to store the food for the timing till it breaks it down, mixes and churns it with enzymes and other digestive fluids and eventually passes it along to the intestine.

Lower Gastrointestinal Tract

The lower GI consists of the following organs:

Small Intestine

The small intestine could also be a coiled thin tube, about 6 meters long , where most of the absorption of nutrients takes place. Food is mixed with enzymes from the liver and therefore the pancreas within the intestine . The surfaces of the tiny intestine functions by absorbing the nutrients from the food into the bloodstream, which carries them to the remainder of the body

Large Intestine

The large intestine, also mentioned because the Colon, could also be a thick tubular organ wrapped around the intestine . Its primary function is to process the waste products and absorb any remaining nutrient and water heater into the system. Stool is made within the body by the remaining waste that's sent to the rectum to urge faraway from the body.

Digestion Process

The alimentary tract or the alimentary canal may be a series of hollow organs and tubes that begins from the mouth cavity and continues into the pharynx, through the stomach, small intestines, large intestines, and eventually ending at the anus. While travelling through the various compartments of the alimentary canal, the food gradually gets into the process of digestion. The digestion process takes place within the following steps.

Ingestion

The very first step involves mastication (chewing). The salivary glands, alongside the tongue, helps to moisten and lubricate food, before being pushed down into the food pipe. 

Mixing and Movement

It involves the process of lubricating and manipulating food and pushing it down the food through the food pipe (using peristalsis), and into the stomach.

Secretion

The stomach, small intestine, liver, and pancreas secrete enzymes and acids to assist the method of digestion. It functions by breaking down food particles into simple components and simply absorbable components.

Digestion

When the complex food particles get converted into simpler substances in the presence of enzymes and acids secreted by different digestive organs, it is termed as the process of digestion. 

Absorption

This process begins within the intestine where most of the nutrients and minerals are absorbed. The excess water in the indigestible matter is absorbed by the large intestines.

Excretion

The process of removing indigestible substances and waste by-products from the body through the method of defecation.

Disorders of the Human Digestive System

Vomiting: it's the ejection of stomach contents through the mouth.

Diarrhoea: It is the abnormal watery bowel movement. Prolonged diarrhoea eventually leads to dehydration.

Constipation: A condition during which the faeces are clutched within the rectum thanks to an irregular movement .

Indigestion: When there is a  pain or discomfort in the stomach which is caused when food is not digested properly, resulting in the feeling of fullness that is known as the process of Indigestion. This is especially caused due to the inadequate enzyme secretion, gastrointestinal disorder, anxiety, overeating and eating spicy foods.

Gastric Secretion 

The gastric mucosa secretes 1.2 to 1.5 litres of digestive juice per day. Gastric juice makes the food particles soluble, helps in digestion (particularly of proteins), and turns the gastric contents to a semiliquid mass called chyme, thus preparing it for further digestion in the small intestine. Gastric juice may be a variable mixture of water, acid , electrolytes (sodium, potassium, calcium, phosphate, sulfate, and bicarbonate), and organic substances (mucus, pepsins, and protein). This juice is very acidic due to its acid content, and it's rich in enzymes. As noted above, the stomach walls are shielded from digestive juices by the membrane on the surface of the epithelial cells bordering the lumen of the stomach; this membrane is rich in lipoproteins, which are immune to attack by acid.