💚 CIRCULATORY SYSTEM
The circulatory system is the transport system of the body. It carries oxygen and food to all cells and removes waste. It also connects all organs so they can work together.
It has three main parts: heart, blood, and blood vessels.
🩸 BLOOD – FLUID OF LIFE
Blood is a red-coloured liquid that flows in blood vessels. It is made of plasma, RBCs, WBCs, and platelets.
RBCs carry oxygen, WBCs fight infections, and platelets help in clotting.
Blood transports oxygen and nutrients, removes waste, protects the body, and keeps it warm.
👉 Remember: Transport + Protection + Warmth
🧵 BLOOD VESSELS
Blood vessels are tubes through which blood flows.
- Arteries carry blood away from the heart (thick walls)
- Veins carry blood towards the heart (have valves)
- Capillaries are very thin and help in the exchange of materials
👉 Easy Trick: A = Away, V = Visit heart, C = Connect
❤️ HEART
The heart is a muscular organ that pumps blood continuously. It is located in the chest and is about the size of a fist.
It has 4 chambers:
- Upper → atria
- Lower → ventricles
The heartbeat makes a “lub-dub” sound.
Normal pulse rate is about 72 beats per minute.
🔁 BLOOD CIRCULATION
Blood keeps moving in a cycle.
Impure blood from the body enters the right side of the heart, goes to the lungs for purification, and becomes oxygen-rich.
Pure blood returns to the left side of the heart and is pumped to the whole body.
The right side of the heart carries impure blood to the lungs, and the left side carries pure blood to the body. Valves ensure one-way flow.
