Science — Study Sheet

🫃 Digestive System

The digestive system breaks down food into nutrients that the body can use for energy, growth and repair.

Organ	What it does
Mouth	Chews food and mixes it with saliva to begin digestion.
Esophagus	Tube that carries food from the mouth to the stomach.
Stomach	Mixes food with acids and digestive juices. Breaks it into a mushy liquid.
Small intestine	Absorbs nutrients from food into the bloodstream. Most digestion happens here.
Large intestine	Absorbs water. Turns leftover material into solid waste.
Rectum & Anus	Store and remove solid waste from the body.

The journey of food:
Mouth → Esophagus → Stomach → Small intestine → Large intestine → Out

Digestion starts in the MOUTH, not the stomach! Saliva already begins breaking down food as you chew.

🫀 How Body Systems Work Together

The body systems do not work alone — they all depend on each other to keep the body healthy and functioning.

System	Main job	Works with
Digestive	Breaks down food into nutrients	Circulatory (delivers nutrients)
Respiratory	Brings oxygen in, removes CO2	Circulatory (carries oxygen)
Circulatory	Transports blood, oxygen & nutrients	All systems

Example of teamwork:
1. You eat food → Digestive system breaks it into nutrients
2. Nutrients enter the blood → Circulatory system carries them
3. You breathe in → Respiratory system adds oxygen to blood
4. Blood delivers oxygen + nutrients to all cells

All systems share one goal: keep every cell in the body alive and working!

🥗 Nutrition and Healthy Eating

What we eat directly affects how our body works. A balanced diet gives the body everything it needs.

🍞CarbohydratesMain source of energy
Bread, rice, pasta, potato

🥩ProteinsBuild and repair muscles and cells
Meat, eggs, beans, milk

🥑FatsEnergy reserve and organ protection
Olive oil, avocado, nuts

🍊VitaminsRegulate body functions and immunity
Fruits, vegetables, greens

🥛Mineral SaltsStrengthen bones, teeth and muscles
Calcium (milk), Iron (meat)

💧WaterEssential for all body functions
Drink 6–8 glasses per day

How eating habits affect the body:
Good habits (balanced diet, exercise, water, sleep) → body systems work in harmony
Poor habits (too much sugar/fat, no exercise) → can lead to obesity, heart disease, low energy

No single food has everything! That is why we need to eat a VARIETY of foods from different groups every day.