GCSE Biology - Blood Vessels #24

This video explores the roles of different blood vessels: arteries, capillaries, and veins. Arteries carry blood away from the heart under high pressure, requiring strong and elastic walls. Capillaries, with their thin and permeable walls, facilitate the exchange of nutrients and waste with tissues. Veins return blood to the heart at low pressure and have valves to prevent backflow. The video also explains how to calculate the rate of blood flow using a simple formula.

What is the primary function of arteries in the circulatory system?

• To exchange gases with tissues

• To carry blood away from the heart

• To store blood

• To filter blood

How are capillaries structurally adapted to their function?

• They have a large lumen for rapid blood flow

• They have walls that are only one cell thick

• They have valves to prevent backflow

• They have thick walls to withstand high pressure

Why is the blood pressure lower in capillaries compared to arteries?

• Because capillaries have a larger total cross-sectional area

• Because capillaries are closer to the heart

• Because capillaries have thicker walls

• Because capillaries have valves

What structural feature of veins helps prevent the backflow of blood?

• Large lumen

• Valves

• Elastic fibers

• Thick muscular walls

How would you calculate the rate of blood flow if 2560 ml of blood passes through the aorta in 8 minutes?

• Divide 2560 by 8

• Multiply 2560 by 8

• Add 2560 and 8

• Subtract 8 from 2560