Human Digestive System: Introduction of Human Digestive System

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Introduction of Human Digestive System

  • Digestion means breaking down food into smaller and smaller components.

  • The digestive system consists of the gastrointestinal tract plus the accessory organs of digestion such as the tongue, salivary glands, pancreas, liver, and gallbladder.

  • This is an important process as it helps living beings to obtain their energy from various sources.

  • This process involves the alimentary canal along with various accessory organs and organ systems.

  • Digestion process is completed by a combination of:

    • Nerves

    • Bacteria

    • Hormones

    • Blood

    • Other organs

Human Digestive System

Human Digestive System

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Parts of the Human Digestive System

Parts of the Human Digestive System

Parts of the Human Digestive System

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Mouth

  • It is the first part of the upper gastrointestinal tract and is equipped with several structures.

  • This includes salivary glands, teeth, and the tongue.

  • The vestibule and the oral cavity proper are the two regions.

  • The area between the teeth, lips, and cheeks is called the vestibule.

  • Most of the oral cavity is lined with oral mucosa, a mucous membrane.

Pharynx

  • This is attached to the terminal end of the mouth.

  • It is fibromuscular y-shaped tube.

  • It is found in vertebrates and invertebrates, though its structure varies across species.

Oesophagus

  • It is a muscular tube connecting the throat (pharynx) with the stomach.

  • It supplies swallowed food along with its length.

Stomach

  • It is a muscular organ located on the left side of the upper abdomen.

  • It receives food from the oesophagus.

  • To maintain the process of digestion, the stomach also produces digestive enzymes and hydrochloric acid.

Small Intestine

  • It is an organ in the gastrointestinal tract.

  • Most of the end absorption of nutrients and minerals from food takes place.

  • It lies between the stomach and large intestine.

Large Intestine

  • It is also known as the large bowel.

  • It is the last part of the gastrointestinal tract and of the digestive system in vertebrates.

  • Water absorption takes place here.

  • The remaining waste material is stored as faeces before being removed by defecation.

Rectum

  • A chamber begins at the end of the large intestine.

  • It immediately following the sigmoid colon, and ends at the anus.

  • The rectum is empty because stool is stored higher in the descending colon.

Accessory Organs

Pancreas

It releases digestive enzymes to complete the process of chemical digestion.

Liver

  • It is a roughly triangular, reddish-brown accessory organ of the digestive system.

  • Bile is produced by pancreas, which helps in the digestion of fat in the small intestine.

Functions of the Human Digestive System

  • Digestive system helps in the process of digestion and absorption.

  • Digestive system is divided into two major parts:

    • The digestive tract (alimentary canal) is a continuous tube with two openings.

    • The mouth and the anus.

  • Digestion takes place in following steps:

    • Ingestion

    • Mixing and Movement

    • Secretion

    • Digestion

    • Absorption

    • Excretion