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Human Body - Food and Digestion

Grade 4ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Nutrients are chemical substances in food that provide energy, help in growth, and protect the body from diseases. The main nutrients are Carbohydrates, Proteins, Fats, Vitamins, and Minerals.

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Carbohydrates are energy-giving foods. They include sugars and starch. For example, glucose is represented as C6H12O6C_6H_{12}O_6.

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Proteins are body-building foods required for growth and repair of damaged tissues.

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Fats provide more energy than carbohydrates and help keep the body warm. Excess fat is stored in the body for future use.

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Vitamins and Minerals are protective foods. They are needed in small quantities to keep the body healthy. Examples include Vitamin AA, BB, CC, DD, and minerals like Calcium (CaCa) and Iron (FeFe).

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Roughage (Fiber) and Water are essential for the proper functioning of the digestive system, although they do not provide nutrients.

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Digestion is the process by which complex food substances are broken down into simpler, soluble forms that the body can absorb.

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The human digestive system consists of the Mouth, Food Pipe (Oesophagus), Stomach, Small Intestine, Large Intestine, and Anus.

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Food preservation techniques include refrigeration, pickling, drying, and canning to prevent food from spoiling due to microbes.

📐Formulae

Starch→SalivaSugar\text{Starch} \xrightarrow{\text{Saliva}} \text{Sugar}

Mouth→Oesophagus→Stomach→Small Intestine→Large Intestine→Anus\text{Mouth} \rightarrow \text{Oesophagus} \rightarrow \text{Stomach} \rightarrow \text{Small Intestine} \rightarrow \text{Large Intestine} \rightarrow \text{Anus}

Balanced Diet=Carbohydrates+Proteins+Fats+Vitamins+Minerals+Roughage+Water\text{Balanced Diet} = \text{Carbohydrates} + \text{Proteins} + \text{Fats} + \text{Vitamins} + \text{Minerals} + \text{Roughage} + \text{Water}

Energy Release: Food+Oxygen(O2)→Energy+Carbon Dioxide(CO2)+Water(H2O)\text{Energy Release: Food} + \text{Oxygen} (O_2) \rightarrow \text{Energy} + \text{Carbon Dioxide} (CO_2) + \text{Water} (H_2O)

💡Examples

Problem 1:

Why is it important to chew food properly in the mouth?

Solution:

Chewing breaks food into smaller pieces and mixes it with saliva.

Explanation:

In the mouth, teeth mechanically break down food, while the enzyme in saliva starts the chemical breakdown of starch into sugar: Starch→Sugar\text{Starch} \rightarrow \text{Sugar}.

Problem 2:

Identify the organ where the maximum absorption of digested food takes place.

Solution:

The Small Intestine.

Explanation:

The walls of the small intestine have a rich supply of blood vessels that absorb the simplified nutrients to be transported to the rest of the body.

Problem 3:

A child has weak bones and teeth. Which mineral might be lacking in their diet?

Solution:

Calcium (CaCa).

Explanation:

Calcium (CaCa) is a vital mineral for the strength and development of bones and teeth. It is commonly found in milk and dairy products.

Food and Digestion - Revision Notes & Key Formulas | ICSE Class 4 Science