6.2 The Blood System

Which structure in the heart acts as a natural pacemaker by initiating the heartbeat?

A. Atrioventricular node

B. Sinoatrial node

C. Purkinje fibres

D. Bundle of His

What is the primary function of valves in the heart and veins?

A. Oxygenate blood

B. Prevent backflow of blood

C. Exchange gases and nutrients

D. Pump blood

Which blood vessels have permeable walls that allow the exchange of materials between blood and tissues?

A. Arteries

B. Veins

C. Capillaries

D. Arterioles

Where does gas exchange occur in the pulmonary circulation?

A. Heart

B. Arteries

C. Lungs

D. Veins

Which component of blood is primarily responsible for oxygen transport?

A. Leukocytes

B. Platelets

C. Plasma

D. Erythrocytes

a) Outline the structure of the heart and explain how it functions as a double pump. [4]

b) Discuss the role of the sinoatrial node in initiating the heartbeat and its significance as the heart’s pacemaker. [3]

a) Describe the composition of blood and explain the function of each component. [4]

b) How do arteries maintain blood pressure between heartbeats, and why is this important? [3]

a) Explain the importance of capillary exchange for nutrient and gas exchange at the cellular level. [3]

b) Discuss the unique anatomy and physiology of pulmonary circulation and how it facilitates gas exchange. [4]

a) Describe the role of valves in the heart and veins in maintaining blood flow and preventing backflow. [3]

b) Explain the function of muscle cells and elastic fibres in arteries. [3]

c) How does the structure of capillaries allow for efficient exchange of materials between blood and tissues? [3]

a) Discuss the cardiac cycle, highlighting the role of valves and pacemaker cells. [4]

b) How does the anatomy of the pulmonary circulation facilitate gas exchange in the lungs? [3]

c) Explain the importance of the sinoatrial node in coordinating heart contractions. [2]