Transportation in Animals and Plants CBSE Class 7 Science Revision Notes

🌟 Why Plants and Animals Need a Transportation System?

• All living beings need food, oxygen, and water to survive.

• These must reach each cell of the body for proper functioning.

• A transport system delivers nutrients, gases, and removes wastes.

• Animals use blood and vessels, plants use xylem and phloem.

🧍‍♂️ TRANSPORTATION IN ANIMALS

Human Circulatory System

• The circulatory system transports food, oxygen, hormones, and waste.

• Main parts: Blood, Blood Vessels, Heart.

🩸 Blood

Definition: Red fluid flowing through blood vessels.

Functions of Blood

• Carries oxygen from lungs to cells.

• Delivers nutrients from intestines to body parts.

• Removes wastes to kidneys for excretion.

• Forms clots at injuries to stop bleeding.

• Regulates body temperature.

• Fights infections with special cells.

Components of Blood

1. Plasma – Liquid part (55%). Transports salts, proteins, sugar.

2. Red Blood Cells (RBCs) – Contain haemoglobin, carry oxygen.

3. White Blood Cells (WBCs) – Fight germs, protect body.

4. Platelets – Help clot blood at injuries.

🩸 Blood Vessels

Arteries

• Carry oxygen-rich blood away from heart.

• Thick walls, high pressure, no valves.

Veins

• Carry carbon dioxide-rich blood to heart.

• Thin walls, low pressure, have valves.

Capillaries

• Thin, tiny vessels connecting arteries and veins.

• Exchange gases and nutrients at tissues.

Pulmonary Artery – Carries deoxygenated blood from heart to lungs.
Pulmonary Vein – Brings oxygenated blood from lungs to heart.

💓 Pulse and Heartbeat

• Pulse: Rhythmic throbbing of arteries as heart pumps.

• Pulse Rate: 70–80 beats/min in adults.

• Heartbeat: Continuous contraction and relaxation of heart muscles.

• Stethoscope: Device used to listen to heartbeat.

🫀 The Human Heart

• Size: Fist-sized organ, in chest cavity, tilted left.

• Divided into four chambers:

  • Right atrium & right ventricle (deoxygenated blood).

  • Left atrium & left ventricle (oxygenated blood).

• Valves prevent mixing of oxygen-rich and oxygen-poor blood.

• Aorta: Largest artery, carries oxygenated blood to body.

• Vena cava: Largest vein, brings deoxygenated blood to heart.

Do All Animals Have Circulatory Systems?

• Sponges and Hydra don’t have blood.

• They exchange gases and nutrients directly with water.

🚽 Excretion in Animals

• Excretion: Removal of toxic waste produced by cells.

• Human Excretory System:

  1. Kidneys – Filter blood, form urine.

  2. Ureters – Tubes carrying urine to bladder.

  3. Urinary bladder – Stores urine.

  4. Urethra – Passes urine out.

Wastes in Different Animals

• Humans: Urea in urine.

• Fish: Ammonia (dissolves in water).

• Birds & reptiles: Uric acid (white paste).

Dialysis – Artificial purification of blood when kidneys fail.

💧 Sweat and Its Importance

• Sweat removes water, salts, and wastes.

• Evaporation of sweat cools the body in summer.

🌱 TRANSPORTATION IN PLANTS

🚰 Transport of Water and Minerals

• Roots absorb water and minerals from soil.

• Root hairs increase surface area for absorption.

• Transport through vascular tissues:

  • Xylem – Carries water & minerals upward (one direction).

  • Phloem – Carries food from leaves to rest of plant (two directions).

🍃 Transpiration

• Process by which plants lose excess water as vapor.

• Takes place through stomata (tiny pores on leaves).

Importance of Transpiration

• Creates suction pull, helps absorb water.

• Cools plant by evaporation.

• Maintains flow of water and minerals in plant.

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📝 KEY DIAGRAMS TO REMEMBER

1. Human Circulatory System – Check Diagram Here

2. Components of Blood – Check Diagram Here

3. Arteries, Veins, Capillaries – Check Diagram Here

4. Human Heart Structure – Check Diagram Here

5. Excretory System – Check Diagram Here

6. Root absorption with hairs – Check Diagram Here

7. Xylem and Phloem transport – Check Diagram Here

8. Transpiration in leaves – Check Diagram Here

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🌟 QUICK REVISION POINTS

• Circulatory system = Blood + Vessels + Heart.

• Blood carries oxygen, nutrients, removes wastes.

• Heart has 4 chambers, beats ~70 times/minute.

• Kidneys filter blood, form urine.

• Dialysis = Artificial kidney when failure occurs.

• Plants transport water through xylem.

• Plants transport food through phloem.

• Transpiration removes excess water and cools plants.