Discussion: (13 marks)
1. Which ventricle has a thicker muscular wall? Explain the importance of the thicker wall to its function.
Left ventricle has a thicker muscular wall (1).
Left ventricle needs to produce a higher blood pressure (1) which pump blood to all parts of the body
(except lungs) / more distant parts of the body (1).
2. Compare the thickness of the wall between atria and ventricles. Explain the significance for this difference. (3 marks)
The walls of atria are thinner (1).
It is because atria only need to pump blood to the ventricles which are closed to the atria (1).
There is no need for atria to have thick muscle to create a large pumping force (1).
3. Make a label for the location of the valves in your drawing. Explain the use of the valves.
As shown in the drawing (1);
The valves prevent the backflow of blood (1).
4. Where are valves found apart from the position between atria and ventricles? What is their function? (2 marks)
They are found at the openings of the arteries (1).
They prevents backflow of blood from the arteries to the ventricles (1).
5. Identify the coronary blood vessels on the surface of the heart. State their functions and explain the outcome if the vessels are blocked. (3 marks)
Coronary arteries supply oxygen and nutrients to the cardiac muscles (1).
If these blood vessels are blocked, the cardiac muscles no longer receive oxygen and become die (1).
The heart cannot beat normally any more/ Coronary heart disease or heart attack is caused (1).