Alimentary canal part and part function

he main organs of the alimentary canal are:

• The Mouth and Oral cavity.
• Esophagus.: It is a muscular tube through which small bolus of food passes from the mouth to the stomach. It is sharply bent at the point at which it meets the stomach. This prevents the backward movement of food from the stomach into it. Food in the digestive tract moves by an involuntary movement of alternate contraction and relaxation of muscles called peristalsis.
• Stomach:

  It is a muscular bag which has three parts- cardiac part, fundus, and body.

• Cardiac part– It is so called because it is present close to the heart. The opening of the esophagus to the stomach is regulated by the cardiac sphincter.
• Fundus– It is dome-shaped and is usually filled with air.
• Body– This is the main part of the stomach. The opening of the stomach into the small intestine is regulated by the pyloric sphincter.
• Largeintestine.The small intestine leads into the large intestine which has three parts- Caecum, Colon, and Rectum.
• Caecum– It is a small sac-like structure at the point where the small intestine meets the large intestine.
• Colon– It is divided into four regions-  transverse colon,  sigmoid colon ascending colon and descending colon.
• Rectum– It opens into the ****.
• Small intestine.:It is the longest part of the alimentary canal and comprises three parts- Duodenum, Jejunum, and Ileum.
• Duodenum– It is C- shaped and receives the hepatopancreatic duct formed by the union of bile and pancreatic duct.
• Jejunum–  Middle part of small intestine with thick walls and more vasculature.
• Ileum– The lower part of the small intestine with thin walls and less vasculature.

• Mouth

The mouth is the opening through which the intake of food occurs.

• Oral cavity

The oral cavity has three parts –the palate, tongue, and teeth.

Palate -It forms the roof of the oral cavity. The anterior part is called hard palate and the posterior part is called soft palate.

Tongue -Tongue is a muscular and glandular structure attached to the base of the oral cavity. On the upper surface, it has a V-shaped furrow called sulcus terminalis. It divides the tongue into the anterior oral part and posterior pharyngeal part. Its upper surface also consists of tiny projections called lingual papillae. Lingual papillae are of three kinds in humans-

(i)Vallate or circumvallate papillae -have gustatory receptors to sense taste

(ii) Filiform papillae- smallest and contain touch receptors.

(iii) Fungi-form papillae- Rounded and mostly present at the tip of the tongue.

• Teeth

Humans are diphyodont i.e. they have two sets of teeth- milk or deciduous and permanent teeth. Here is the list of different types of teeth in humans with their functions.