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Each part: 0.5 Mark
The alimentary canal can be divided into various compartments:-
1. Buccal cavity (Mouth)
2. Oesophagus
3. Stomach
4. Small intestine
5. Large intestine
6. Anus

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Functions: 1 Mark each
1. The tongue is the part thatmixes saliva with the food while chewing and helps in swallowing food. It has taste buds on its surface which help in detection of taste.
2. The gallbladder is theorgan which stores bile. Bile is required for the breakdown of fats.
3. The small intestine is thelongest part of the alimentary canal, most of the digestion and absorption of food takes place here.
4. Villi present in the small intestine increase the overall surface area for absorption.
5. Teeth help in chewing the foodand breaking it down mechanically into small pieces.

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Digestion in the mouth: 1 Mark each
1. Chewing food accomplishes the chemical, as well as the physical breakdown of food.
2. There are three sets of salivary glands in humans: parotid(just below the ear), submandibular(below the lower jaw), and sublingual (below the tongue).
3. These glands produce saliva, which passes down a short duct into the oral cavity. Salivais a fluid which isrich in ions and contains amylase.
4. This digestion of starch starts with the action of saliva. It alsowets and lubricates the food particles.
5. It helps in killing the bacteria that accidentally enter along with the food.

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Thebile duct allows passage of bile juices fromthe liver and the gall bladder to the duodenum.

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Use: 1 Mark
Location: 1 Mark
Saliva helps in breaking down complex components like starch into simple sugars. It brings about partial digestion of starch. This makes it easier for the body to digest the food.
Saliva also helps in lubrication of food.
Saliva is secreted by the salivary glands which are present in the buccal cavity.

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Definition: 1 Mark
Direction: 1 Mark
Peristalsis is a series of wave-like muscle contractions that help in moving food to different processing areas in the digestive tract.
The process of peristalsis begins in the oesophagus when a bolus of food is swallowed and moves till the anus.

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Egestion: 1 Mark
Difference: 1 Mark
The expulsion of undigested food from the gut through the anus is egestion.
Egestion is different from excretion because excretion involves the removal of any waste productthat isgenerated in the body, while egestion is the removal of undigested waste material from the gut through the anus.

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Each point:1 Mark
1. A microscopic outgrowth on the surface of some tissues and organs, which serves to increase the surface area of the organ is called villi.
2. Numerous villi line the interior of the small intestine.Their shape may vary from finger-like (in the duodenum) to spade-like(in the ileum).
3. Intestinal villi are specialized for the absorption of soluble food material.Each villus contains blood vessels and a lymph vessel.

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Definition: 1 Mark
Function: 1 Mark
Digestion: 1 Mark
Gastric glands are microscopic glandular cells present in the inner lining of the stomach.
The function of the gastric glands is to secrete a gastric juice comprising HCl, pepsin and prorennin.
This gastric juice helps in the digestion of proteins.

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Definition: 1 Mark
Requirements: 1 Mark
The absorption of nutrients into the body after digestion and its utilization by the body is called assimilation.
Two processes which happen before assimilation are digestion and absorption.