The Human Body Systems chart displaying illustrations and labels for each major system.

Explanation:
We need to fill in a table about the human body systems shown. The columns are:

1. Nervous System
2. Digestive System
3. Respiratory System
4. Circulatory/Cardiovascular System
5. Skeletal System
6. Muscular System

For each system, we answer three questions:
- What does it do? (main function)
- What organs are involved? (key organs)
- Give an example of a time when you are using this system. (real-life situation)

Let’s go one by one:

1. Nervous System
- What does it do? → Controls and coordinates body activities; sends signals between brain, spinal cord, and body parts.
- Organs involved? → Brain, spinal cord, nerves.
- Example? → When you touch something hot and pull your hand away quickly.

2. Digestive System
- What does it do? → Breaks down food into nutrients the body can use; gets rid of waste.
- Organs involved? → Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas.
- Example? → When you eat lunch and your stomach digests the food.

3. Respiratory System
- What does it do? → Brings oxygen into the body and removes carbon dioxide.
- Organs involved? → Nose, trachea, bronchi, lungs, diaphragm.
- Example? → When you breathe in during gym class or while running.

4. Circulatory/Cardiovascular System
- What does it do? → Moves blood (with oxygen, nutrients, hormones) around the body; removes waste like CO₂.
- Organs involved? → Heart, blood vessels (arteries, veins, capillaries), blood.
- Example? → When your heart beats faster after climbing stairs.

5. Skeletal System
- What does it do? → Supports the body, protects organs, helps movement, stores minerals, makes blood cells.
- Organs involved? → Bones (e.g., skull, ribs, femur), joints, cartilage.
- Example? → When you stand up straight — your spine and leg bones hold you up.

6. Muscular System
- What does it do? → Allows movement of the body; keeps heart beating and food moving through gut.
- Organs involved? → Skeletal muscles (like biceps, quadriceps), smooth muscle (in intestines), cardiac muscle (heart).
- Example? → When you lift your backpack — your arm muscles contract.

Now, we format the answers clearly for the table.

Final Answer:
| System Name | What does it do? | What organs are involved? | Give an example of a time when you are using this system. |
|-------------|------------------|----------------------------|------------------------------------------------------------|
| Nervous System | Controls and coordinates body activities; sends signals | Brain, spinal cord, nerves | Touching something hot and pulling your hand away quickly |
| Digestive System | Breaks down food into nutrients; removes waste | Mouth, esophagus, stomach, small/large intestines, liver, pancreas | Eating lunch and digesting the food |
| Respiratory System | Brings in oxygen and removes carbon dioxide | Nose, trachea, bronchi, lungs, diaphragm | Breathing heavily while running in gym class |
| Circulatory/Cardiovascular System | Transports blood with oxygen, nutrients, and waste | Heart, arteries, veins, capillaries, blood | Heart beating faster after climbing stairs |
| Skeletal System | Supports body, protects organs, helps movement, makes blood cells | Bones (skull, ribs, femur), joints, cartilage | Standing upright — spine and leg bones hold you up |
| Muscular System | Enables movement; keeps heart beating and digestion going | Skeletal muscles (biceps, quads), smooth muscle, cardiac muscle | Lifting your backpack with your arm muscles |