Welcome to GattPrep!
Ever wondered how nutrients from your food or the oxygen you breathe reaches every corner of your body? Say hello to your circulatory system—your body’s delivery and cleanup service!
The circulatory system is a powerful network of blood, vessels, and the heart. It delivers oxygen and nutrients to your cells, removes waste like carbon dioxide, and helps defend against diseases. In this lesson, you’ll explore how this amazing system works, what it’s made of, and why it’s so important to your health.
The circulatory system (also called the cardiovascular system) is the body’s transport system. It consists of:
The heart: a muscular pump
Blood vessels: tubes that carry blood
Blood: the fluid that transports substances
The heart has four chambers:
Two upper chambers: left atrium and right atrium
Two lower chambers: left ventricle and right ventricle
It has valves that ensure blood flows in one direction.
The heart pumps blood in two loops:
Pulmonary circulation: between heart and lungs
Systemic circulation: between heart and body
| Vessel | Function | Example |
|---|---|---|
| Arteries | Carry blood away from the heart | Aorta |
| Veins | Carry blood to the heart | Vena cava |
| Capillaries | Tiny vessels where gas/nutrient exchange occurs | Capillaries in lungs, muscles |
🔍 Arteries carry oxygen-rich blood (except the pulmonary artery); veins usually carry oxygen-poor blood (except the pulmonary vein).
| Component | Function |
|---|---|
| Red Blood Cells (RBCs) | Carry oxygen using haemoglobin |
| White Blood Cells (WBCs) | Fight infections |
| Platelets | Help blood to clot |
| Plasma | Yellowish liquid carrying nutrients, hormones, and waste |
Deoxygenated blood from the body enters the right atrium.
It moves to the right ventricle, then to the lungs via the pulmonary artery.
In the lungs, blood gets oxygen and releases carbon dioxide.
Oxygenated blood returns to the left atrium via the pulmonary vein.
It moves to the left ventricle, which pumps it through the aorta to the rest of the body.
🩸 This flow is continuous and essential for life.
| Disorder | Description | Prevention |
|---|---|---|
| High blood pressure (Hypertension) | Increased pressure in blood vessels | Exercise, reduce salt, healthy diet |
| Anaemia | Lack of red blood cells or haemoglobin | Eat iron-rich foods (e.g., spinach, liver) |
| Leukaemia | Cancer of blood-forming tissues | Early diagnosis, treatment |
| Hole-in-heart | Birth defect in heart wall | Surgery may be required |
| Stroke | Blockage or bleeding in brain blood vessels | Control blood pressure, avoid smoking |
🧠 Problem: Yaw is dizzy and his doctor says he has low red blood cell count. What is the likely diagnosis, and how can he recover?
✅ Step-by-Step Solution:
Low RBC means reduced oxygen delivery = anaemia.
Symptoms may include tiredness and dizziness.
Treatment: eat foods rich in iron and folic acid, or take supplements.
✔️ Answer: Yaw likely has anaemia. He should eat iron-rich foods like spinach, beans, or meat to recover.
(a) The heart has ______ chambers.
(b) Blood vessels that carry blood to the heart are called ______.
Answers:
(a) four
(b) veins
| Part | Function |
|---|---|
| (i) Platelets | A. Carry oxygen |
| (ii) Plasma | B. Help in clotting |
| (iii) Red Blood Cells | C. Transport nutrients and waste |
Answers:
(i) → B
(ii) → C
(iii) → A
Q: What is the main function of capillaries in the circulatory system?
A: Capillaries allow the exchange of oxygen, nutrients, and waste between blood and body cells.
Let’s go over what you learned:
The circulatory system includes the heart, blood, and vessels.
It transports oxygen, nutrients, and waste around the body.
Blood is made up of RBCs, WBCs, platelets, and plasma.
The heart pumps blood through pulmonary and systemic circulation.
Disorders include anaemia, high blood pressure, and leukaemia.
Put your fingers on your wrist or neck. Feel your pulse? That’s your circulatory system in action!
Now ask yourself:
What might happen if blood didn’t flow properly to parts of the body?
Write your thoughts in your science journal or share them with your teacher or classmates!
English