The Human Circulatory System – Blood Vessels Basic 6 Basic Technology Lesson Note

Learning Objectives

By the end of the lesson, pupils should be able to:

• Name and identify blood vessels
• State the function of blood vessels
• Differentiate among arteries, veins and capillaries
• Describe how food and materials are distributed by blood
• Draw blood vessels

Content

What are Blood Vessels? Blood vessels are tubes that carry blood throughout the body. They connect all parts of the body to the heart.

Types of Blood Vessels

1. ARTERIES

• Carry blood AWAY from the heart
• Carry oxygenated blood (except pulmonary artery)
• Have thick, elastic walls
• Blood flows under high pressure
• No valves (except at heart exit)
• Example: Aorta (main artery from heart)

2. VEINS

• Carry blood TOWARD the heart
• Carry deoxygenated blood (except pulmonary vein)
• Have thinner walls than arteries
• Blood flows under low pressure
• Have valves to prevent backflow
• Example: Vena cava (main vein to heart)

3. CAPILLARIES

• Tiny blood vessels connecting arteries to veins
• Have very thin walls (one cell thick)
• Allow exchange of oxygen, nutrients, and waste
• Found in all body tissues
• Connect to every cell in the body

Circulation of Blood

1. Heart pumps blood to lungs (to collect oxygen)
2. Oxygenated blood returns to heart
3. Heart pumps oxygenated blood to body through arteries
4. Capillaries deliver oxygen and nutrients to cells
5. Capillaries collect waste products and carbon dioxide
6. Blood returns to heart through veins
7. Cycle repeats continuously

Functions of Blood Vessels

1. Transport oxygen to body cells
2. Carry nutrients from digested food to cells
3. Remove waste products (carbon dioxide, urea)
4. Help regulate body temperature
5. Transport hormones and chemicals
6. Fight infections by carrying white blood cells

Activities

• Draw and label blood vessels
• Use red and blue to show oxygenated and deoxygenated blood
• Create a flow chart of blood circulation
• Feel pulse to observe blood flow