Review of Digestive System

The alimentary canal, a few assessory organs, and a number of digestive processes are all collectively referred to as the digestive system. The mouth is where the digestive system begins and the anus is where it terminates. The term "digestive tract" refers to the entire tract. Food is broken down in the digestive tract so that the body can consume it. The digestive system is made up of a number of organs that work together as a coordinated framework to digest and absorb nutrients and expel waste materials as feces. Digestion is the process through which food is broken down into smaller pieces and transformed into forms that the body can absorb.

Organs of digestive system

The alimentary tract: 

• Oral/Mouth cavity:
  • Food is chewed with the aid of the tongue, teeth, and salivary glands in the mouth. The tongue aids in the mixing of saliva, food swallowing, and flavor perception.
    Pharynx: The pharynx is a mucous membrane-lined muscle chamber. The nasopharynx, oropharynx, and laryngopharynx are its three component sections. The meal is helped along the way to the oesophagus.
• Oesophagus:
  • The oesophagus serves as a tube or duct that transports food from the mouth to the stomach. Dysphasia is a condition where a person has trouble swallowing solids or liquids because of an illness or oesophageal motility problem, and it has to be looked into.
• Stomach:
  • The hydrochloric acid in the stomach and the pepsin in gastric juice transform food into a digestible form.
• Small intestine:
  • It consists of the duodenum, jejunum, and ileum. In our abdomen, it is set up like a coil. Its purpose is to perform residual digestion and absorption with the use of different enzymes in the small intestine, pancreatic juice, and bile sections.
• Large intestine:
  • The large intestine begins in the caecum, to which the appendix is connected. Then it continues as the rectum, anal canal, anus, pelvic/sigmoid colon, transverse colon, and descending colon. The large intestine's primary function is the residual absorption and excretion of the body's solid wastes (feces) through the anus.

Accessory organs

Organs that are both partially associated with the digestive system and other systems are referred to as accessory organs. These consist of:

1. Salivary glands
2. Pancreas
3. Liver

• Peristalsis:
  • A wave-like automatic contraction of the alimentary canal causes the food to flow downhill. Peristalsis is the term for it.
• Sphincters:
  • At various points in the alimentary canal, there are sphincters (muscula valves) that control the one-way passage of food. The sphincter at the junction of the stomach and esophagus is known as the "cardia sphincter," while the sphincter at the anus is known as the "anal sphincter" and the one at the junction of the stomach and ileum as the "leocecal sphincter." With the exception of ar sphincter, all sphincters are involuntary.
• Pancreas:
  • It is located behind the stomach and releases bile duct and exocrine secretions through pancreatic duct, which it opens in the duodenum through the ampulla of vater. The digestive process depends on these secretions. The regulation of carbohydrate metabolism is a problem of the pancreas' endocrine secretions (insulin, glucagons).

Exocrine pancreatic enzymic principlas are:

• Amylase (carbohydrate splitting factor)
• Trypsin (Protein splitting factor) or proteolytic
• Lipase (Fat splitting factor)

Exocrine pancreatic secretion is stimulated partly through nervous & partly through hormonal mechanism & a maximum flow is reached between 2 & 3 hours after a meal. In all about 1 litre is secreted daily. Deficiency of insulin (an endocrine secretion) leads to a disease called diabetes mellitus.

Digestive enzymes:

By means of amylotic enzymes, food's carbohydrates are broken down into glucose, fructose, galactose, and other sugars (Present in saliva of mouth & intestinal mixed juices). Juices from the small intestine and the pancreas secreted into the intestine are referred to as intestinal mixed juices.

The functions of digestive system:

• Ingestion: Taking food into one's digestive tract is referred to as ingestion.
• Digestion: Food is broken down mechanically during digestion, and enzymes break it down chemically..
• Absorption: Digested nutrients pass through the alimentary canal's wall during absorption.
• Elimination: Food substances that have been consumed but are unable to be digested and absorbed are eliminated as feces.