1. Introduction to the Digestive System
- The digestive system is responsible for breaking down food, absorbing nutrients, and eliminating waste.
- Major organs include the mouth, oesophagus, stomach, small intestine, large intestine, and anus.
2. Small Intestine
Structure & Function
- A 7-meter (23 feet) long narrow tube starting from the stomach and ending at the large intestine.
- Primary site for chemical digestion and nutrient absorption.
Parts of the Small Intestine
- Duodenum – Shortest section; major site of chemical digestion.
- Jejunum – Absorbs nutrients into the blood.
- Ileum – Absorbs remaining nutrients before passing food to the large intestine.
3. Large Intestine
Structure & Function
- Wider but shorter than the small intestine.
- Absorbs water from undigested food and passes it to the kidneys.
- Converts waste into faeces, which are excreted through the anus.
4. Digestive Glands
4.1 Pancreas
- Secretes digestive enzymes to break down proteins, fats, and carbohydrates.
- Produces insulin, the key hormone for metabolizing sugar.
4.2 Liver
- Processes nutrients absorbed from the small intestine.
- Secretes bile into the small intestine, aiding in digestion of fats and vitamins.
- Functions as the body’s chemical factory.
5. Digestive System in Ruminants (e.g., Goats)
- Food is digested in a long, coiled small intestine.
- Bile from the liver and pancreatic juice aid digestion.
6. Digestion Process
6.1 Oesophagus (Food Pipe)
- Transports food from the mouth to the stomach.
- Moves food through peristalsis (muscular contractions).
6.2 Stomach
- Churns food into a fine paste using muscular contractions.
- Hydrochloric acid & digestive juices break down food.
- Absorbs water, salt, and simple sugars.
6.3 Absorption of Nutrients
- Digested nutrients enter the bloodstream to nourish body cells.
6.4 Elimination
- Indigestible substances are removed as solid waste (faeces).
7. Role of the Mouth in Digestion
7.1 Functions of the Mouth
- Saliva softens food, beginning the digestion process.
- Teeth chew food into smaller pieces.
- Tongue helps in tasting, chewing, and swallowing.
- Salivary glands secrete saliva to moisten food.
7.2 Types of Digestion
- Mechanical Digestion – Physical breakdown of food (e.g., chewing, stomach churning).
- Chemical Digestion – Enzymatic breakdown of food into nutrients.
8. Importance of Food & Digestion
8.1 Role of Food in the Body
- Provides energy, growth, and repair.
- Supplies nutrients necessary for cell functions.
8.2 Types of Food Sources
- Plant-based foods: Fruits, vegetables, cereals, pulses.
- Animal-based foods: Milk, eggs, meat, fish, honey.
9. Functions of the Digestive System
- Breaks down food into nutrients.
- Absorbs nutrients into the bloodstream.
- Eliminates waste from the body.
10. Summary
- The digestive system ensures food is broken down and absorbed properly.
- Muscles, enzymes, and digestive juices work together to process food.
- Proper digestion supports overall health and energy levels.
Class 5th – Science – Question Paper – Digestive System by The Busy Brains on Scribd
