Functions of Human Body Systems

Science 4: Major Organ Systems & Their Primary Roles

Grade 4 Science

Page 1 of 4

Name:

Date:

Score: / 10

🦴 Skeletal System

Provides body frame, protects organs (skull, ribs), makes blood cells in marrow, and stores minerals.

💪 Muscular System

Contracts and relaxes to produce movement, maintains posture, and helps pump blood and move food.

🍎 Digestive System

Breaks food down into usable nutrients, absorbs energy into the bloodstream, and eliminates solid waste.

❤️ Circulatory System

Pumps blood, transports oxygen and nutrients to cells, and carries away carbon dioxide and waste.

🫁 Respiratory System

Inhales life-sustaining oxygen (O₂), performs gas exchange in air sacs, and exhales carbon dioxide (CO₂).

🧠 Nervous System

Master control network: receives sensory signals, controls thinking, reflexes, memory, and organ coordination.

Part A: System Match Write the name of the correct organ system that matches each primary function.

1 Transports oxygen, nutrients, and hormones to all body cells via blood:

2 Shields delicate organs (like brain and heart) and forms new red blood cells:

3 Takes in oxygen from the air and expels gaseous carbon dioxide waste:

4 Receives information from the 5 senses and coordinates reflex actions:

5 Contracts and pulls on bones so you can run, jump, smile, and write:

6 Breaks solid food into chemical nutrients that your body cells can absorb:

Part B: Detective Riddles Read each clue carefully. Name the specific Human Body System described.

Riddle #1: The Unstoppable Pump

“I never sleep, even when you do! I have a muscular pump and miles of highways (arteries and veins) to keep warm red fluid flowing to your toes.”

System:

Riddle #2: The Armor & Frame

“Without me, your body would flop like a jellyfish on the ground! I have 206 hard parts in adults, and my strong helmet protects your brain.”

System:

Riddle #3: The Chemical Blender

“From teeth to stomach acid, I turn your chicken adobo and rice into microscopic energy, sending nutrients through long winding tubes.”

System:

Riddle #4: The Lightning Messenger

“When your finger touches an ice cube or a sharp pencil, my electrical signals travel faster than a racing car to your brain and back!”

System:

Organ Classification & Teamwork

Science 4: Organ Identification & How Systems Work Together

Grade 4 Science

Page 2 of 4

Name:

Date:

Score: / 12

Part C: Organ Classification Identify which organ system each major organ belongs to and review its primary job.

Major Organ	Organ System	Primary Function / Job
1. Trachea (Windpipe)		Passageway that conducts air between larynx and lungs.
2. Femur (Thigh Bone)		Supports upper body weight and enables walking and running.
3. Stomach		Churns food with gastric acid into liquid chyme.
4. Heart		Pumps oxygen-rich blood through arteries to body tissues.
5. Biceps Muscle		Contracts to flex and bend the arm at the elbow joint.
6. Brain (Cerebrum)		Controls conscious thought, memory, speech, and decisions.
7. Kidneys		Filters liquid waste, toxins, and excess water from blood.
8. Alveoli (Air Sacs)		Microscopic balloons in lungs where gas exchange occurs.

Part D: System Teamwork No system works alone! Analyze each real-life scenario and name the two systems collaborating.

🏃 1. Sprinting in P.E. Class

Mateo's leg muscles contract rapidly to move his bones forward, while his joints allow smooth bending at the knee and hip.

Collaborating Systems:

🥪 2. Absorbing Morning Fuel

Sarah's small intestine digests her breakfast egg sandwich, and microscopic capillaries absorb nutrients to deliver energy to cells.

Collaborating Systems:

🔥 3. The Hot Pot Reflex

Ken accidentally brushes against a hot pan. Nerve endings in his skin instantly trigger an electrical signal, pulling his arm away in a split second!

Collaborating Systems:

🌬️ 4. Deep Breathing After Swimming

After swimming laps, Chloe pants deeply. Her lungs pull in oxygen, and her pounding heart delivers oxygenated blood to tired arm and leg muscles.

Collaborating Systems:

Critical Thinking & Body Care

Science 4: Fact-Checking, Healthy Habits & Scientific Inquiry

Grade 4 Science

Page 3 of 4

Name:

Date:

Score: / 8

Part E: Fact or Myth Circle TRUE if the science statement is correct, or FALSE if it is incorrect.

1

Bones are completely dry, dead mineral sticks that only provide shape to our body.

TRUE FALSE

2

The digestion process starts in your mouth with teeth chewing and saliva breaking down starch.

TRUE FALSE

3

The heart is a hollow organ made almost entirely of involuntary cardiac muscle tissue.

TRUE FALSE

4

Your lungs have their own large skeletal muscles inside them that actively pump air.

TRUE FALSE

5

The brain, spinal cord, and sensory nerves work together to coordinate both voluntary actions and reflexes.

TRUE FALSE

Part F: Junior Doctor Care Match each healthy habit to the primary body system it directly protects and strengthens.

🥛

Drinking milk & eating leafy greens rich in calcium

Protects:

⛑️

Wearing a certified helmet while biking or skating

Protects:

🏃‍♂️

30 minutes of aerobic jumping jacks and brisk jogging

Protects:

💧

Drinking 8 to 10 glasses of clean water every day

Protects:

🥗

Chewing food thoroughly and eating fiber-rich papaya

Protects:

Part G: Science Inquiry & Critical Reflection 2 Points

Explain in 2 to 3 complete sentences: Why is it impossible for a human being to survive if even one major organ system (such as the circulatory or respiratory system) completely stops functioning?

Answer Key & Teacher Guide

Solutions, Scoring Rubrics & Pedagogical Diagnostics

Grade 4 Science

Page 4 of 4

Student:

Date Evaluated:

Total Score: / 30

Part A: System Matching 6 Points

1. Circulatory System (Transports O₂, nutrients via blood)
2. Skeletal System (Protects brain/heart, marrow makes RBCs)
3. Respiratory System (Inhales O₂, expels CO₂ gas)
4. Nervous System (Sensory reception, reflex coordination)
5. Muscular System (Pulls bones, creates voluntary movement)
6. Digestive System (Breaks food into absorbable nutrients)

Part B: Detective Riddles 4 Points

1. Circulatory System (Heart pump, blood vessel highways)
2. Skeletal System (206 bones, cranial skull helmet)
3. Digestive System (Teeth, stomach acid, intestinal tube)
4. Nervous System (Electrical signals, rapid nerve impulses)

Part C: Organ Classification 8 Points

1. Trachea: Respiratory System
2. Femur: Skeletal System
3. Stomach: Digestive System
4. Heart: Circulatory System
5. Biceps: Muscular System
6. Brain: Nervous System
7. Kidneys: Excretory / Urinary System
8. Alveoli: Respiratory System

Part D: System Teamwork 4 Points

1. Muscular + Skeletal (Musculoskeletal movement)
2. Digestive + Circulatory (Nutrient delivery to cells)
3. Nervous + Muscular (Reflex arc to pull arm back)
4. Respiratory + Circulatory (O₂ gas exchange & delivery)

Part E: Fact or Myth (T / F) 5 Points

1. FALSE (Bones are living tissue with blood vessels and marrow)
2. TRUE (Amylase in saliva begins chemical carbohydrate digestion)
3. TRUE (Myocardium is involuntary cardiac muscle tissue)
4. FALSE (Lungs lack muscles; the diaphragm and rib muscles expand them)
5. TRUE (Nerves coordinate voluntary motion and involuntary reflexes)

Parts F & G: Care & Reflection 5 + 2 Points

F1. Milk/Calcium: Skeletal System (bone density)
F2. Helmet: Nervous System (protects brain/skull)
F3. Cardio Exercise: Circulatory / Muscular
F4. Water Intake: Excretory / Digestive
F5. Fiber / Chewing: Digestive System
G. Reflection Rubric: Full credit (2 pts) if student explains that all cells require continuous oxygen (Respiratory) and food nutrients (Digestive) transported by blood (Circulatory); if one system halts, cells starve or suffocate, causing organ failure.

Diagnostic Performance Benchmarking (Total Score: 30 Points)

★ Master Level (27–30)

90% – 100% Score

Exemplary mastery of organ roles and system interdependence. Ready for advanced Grade 5 cellular and ecosystem concepts.

✓ Proficient (22–26)

73% – 89% Score

Solid conceptual grasp of primary organs. Review the difference between lung tissue and the diaphragm in Part E.

▲ Needs Reinforcement (<22)

Below 73% Score

Struggles with system teamwork and organ pairing. Recommended for a targeted PERSONALIZED diagnostic review session.

Pedagogical Insight for Tutors & Parents: Grade 4 students frequently hold the misconception that lungs inflate by themselves like balloons with muscles. Emphasize that the diaphragm muscle below the lungs does the physical pumping work. Furthermore, reinforce that the Circulatory System is the “delivery highway” connecting the Digestive and Respiratory systems to all living cells.