What is Digestive System?

The digestive system consists of the liver and gallbladder, and gastrointestinal tract (also known as the G.I. tract). The G.I. tract is a series of hollow organs connected by a long, twisted tube that runs from the mouth to the anus. The mouth, esophagus, liver, small digestive tract, internal organ, and rear-end are the hollow organs that make up the human digestive system or G.I. tract.

Why is the Digestion System Important for the Body?

The digestive system helps in digestion which ultimately results in the formation of energy from food and water.

It helps in the breakdown of,

• Proteins into amino acids
• Fats into fatty acids and glycerol
• Carbohydrate into sugars

When food is ingested, the physical process of chewing leads to the breakdown of food into smaller particles. These smaller particles mixed with saliva and lead to the formation of a bolus of food. The chemical digestion of bolus in the stomach and intestine leads to forming a basic nutrient molecule (glucose). The assimilation of the basic nutrient is carried out from the small intestine, which leads to the distribution of nutrients throughout the body.

What is Present in the Body, and how the Food Moves?

Food Pathway

• Mouth: Food starts to go through the G.I. tract bundle when one eats. A mucous membrane surrounds it. The food is pushed into the mouth by the tongue as you swallow. To prevent choking in the esophagus, a small crease of tissue called the epiglottis folds over your windpipe, allowing food to pass through the G.I. tract.
• Lower oesophageal sphincter: Exactly when food shows up toward the completion of your throat, a ring-like muscle. This sphincter generally stays shut to keep what's in your stomach away from streaming again into your throat.
• Stomach: The stomach muscles combine the food and liquid with stomach-related juices after it reaches the stomach. The stomach slowly cleanses its substance, called chyme, into your little stomach-related lot. It is a sac-like structure.
• Small intestine: The little stomach-related framework muscles mix food with stomach-related juices from the pancreas, liver, and stomach-related framework and push the blend forward for extra osmosis. The dividers of the little stomach-related plot ingest water and the handled enhancements into your circulatory framework. As peristalsis continues, the symptoms of the stomach-related communication move into the interior organ.
• Large intestine: Here, the food extra all nutrients and the excessive remaining water is absorbed and transfer to the body cells. The remaining material remains there and is converted to waste product which we know as stool which is later stored in the rectum.
• Rectum: The rectum, the lower end of your stomach-related gland, retains stool until a strong release forces it out of your backside. Anus has specific muscles which regulate bowel movement.

Juices/Chemicals/Enzymes Encounter by the food in the Tract

• Saliva: Salivary organs make spit, a digestive juice, which saturates food, so it moves all effectively through your throat. Salivation additionally has a chemical that starts to separate starches in your food. So after swallowing, peristalsis drives the food down your throat into your stomach.
• Pancreatic juice: The pancreas makes digestive juices with compounds that separate carbs, fats, and proteins. It conveys the digestive juices to the small intestine through channels. 
• Bile: The liver makes digestive juices considered bile that helps to digest fats and a few nutrients. Bile channels convey bile from the liver to the gallbladder for capacity.
• Bile duct: The bile duct refers to the framework of thin tubes that go from the liver to the small intestine and allow bile juice to travel along with the liver, gallbladder to the small intestine.
• Gall bladder: The gallbladder stores bile. At the point when one eats, the gallbladder barely gets bile through the bile ducts into your small digestive tract.

Intestines (Absorption)

Small intestine: The small intestine receives bile and pancreatic juice to finish the breakdown of proteins, starches, and fats. Microorganisms make a portion of the chemicals that are used to digest sugars in the small intestine. To help break down food, the small intestine system transfers water from your circulation system into the G.I. tract.

Large intestine: Microbes in the digestive tract assist break with bringing down excess supplements and make nutrients. Side-effects of absorption, including portions of food that are still too enormous, become stool.

The Reaction of Body Cells towards Digested Food

• The small intestine is the part of the G.I. tract where the absorption of basic nutrients takes place. Cells help nutrient molecules cross the intestinal covering into the circulatory system. The blood transfers the basic sugars, amino acids, glycerol, and other nutrients and salts to the liver.
• The lymph network connects vessels that convey white platelets and a liquid called lymph throughout the body to battle contamination, ingests unsaturated fats and nutrients.
• Your body utilizes sugars, amino acids, unsaturated fats, and glycerol to fabricate substances you need for energy, development, and cell fix.

Digestive System Regulation relate to Body Signals

The chemicals and nerves cooperate to help control digestion.

Chemical Digestion or Chemical Digestive System

Cells of the stomach and small digestive tract make and deliver chemicals that control how the digestive framework must function. For example, these chemicals signal the body to start churning food and signal the body when one feels satiated. The pancreas additionally makes chemicals that are essential to absorption and makes the process of digestion easy.

Nerves

Nerves of the nervous system attach nerves from the cerebrum and spinal cord to the digestive tract and regulate certain stomach-related potentials. For example, when you see or smell food, the cerebrum sends a signal to the salivary glands, which causes the mouth to "water" (salivate).

Enteric Sensory System (ENS)

The ENS controls the digestive system. The nerves convey messages to control the activities of the gut muscles to agree and unwind to push food through the digestive tract.

Common Diseases of the Digestive System

Common digestive diseases include:

1. Rectal issues: Anal fissure, hemorrhoids, proctitis, rectal prolapse, irritable bowel movement, diarrhea, and constipation.
2. Throat issue: Injury (narrowing) and achalasia, and esophagitis.
3. Stomach issue: Gastritis, gastric ulcers typically brought about by Helicobacter pylori disease and malignant growth.
4. Liver issues: Hepatitis B or hepatitis C, cirrhosis, liver disappointment, immune system, and alcoholic hepatitis.
5. Small Intestinal and large intestinal issues: Polyps and malignant growth, contaminations, celiac illness, Crohn's infection, ulcerative colitis, diverticulitis, malabsorption, and irritable bowel syndrome.

These Diseases Possess some Common Symptoms such as

• Swelling
• Blockage
• Loose bowels
• Acid reflux
• Incontinence
• Sickness and heaving
• Agony in the stomach
• Gulping issues
• Weight gain

COVID-19 and Human Digestive System 

• Covid-19 has been seen affecting the patient's digestive system, mostly in 50.5% of suffering patients irregular bowel moments, diarrhea, stomach ache can be seen, and these symptoms are so severe that doctors are considering diarrhea and consistent abdominal swelling the factor symptom of COVID.
• In severe cases, diarrhea and vomiting cause dehydration. The whole digestion system fails to digest food and absorb energy, which results in the necessity of artificial glucose in hospitals. It can cause an intestine ulcer also.

Context and Application

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for;

• MBBS entrance exams
• Bachelors in human anatomy, biology, and biochemistry
• Masters in human anatomy, biology, biochemistry, and applied sciences
• Pharmaceuticals
• Human microbiology

Related Concepts

• Human Microflora
• Human Anatomy
• Digestive enzymes and their working
• Body metabolism (catabolism and anabolism)
• Food Cycle
• Biochemistry Cycles
• Human diseases and treatment
• Tissues working and specificity
• Small intestine and large intestine work in human food regulation
• Digestion genetic disorders