Question 1
Which was a feature of Galen's theory of blood flow prior to his theory being superseded by that of William Harvey?
Blood flows in a closed loop
Blood is constantly re-used throughout a day
The heart is a pump
Blood flow is bidirectional
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DP IB Biology: SL
Topic Questions
6.2 The Blood System
Question 2
A student studied the structure of a blood vessel and found:
- An innermost layer of endothelial cells
- A thick middle layer of smooth muscle and elastic tissue
- An outer layer of collagen fibres
Which vessel was the student studying?
Vein
Capillary
Venule
Artery
Question 3
The aquatic crustacean the water flea (Daphnia magna, pictured below) has a heart that pumps blood-like liquid called hemolymph around its body cavity. 
Which statement about Daphnia magna's circulatory system is correct?
single closed
single open
double closed
double open
Question 4
The graph shows changes in pressure at various stages of the cardiac cycle.
Which statement describes the events at point Y of the graph?
Ventricular systole
The ventricle contracts
↓
Pressure in the left ventricle goes higher than in the aorta
↓
Aortic valve opens and blood is forced into the aorta
Early diastole
Left ventricle is empty
↓
Muscles in the walls of the left ventricle relax and pressure drops below the pressure in the aorta
↓
Aortic valve closes
Diastole
The relaxed left atrium fills with blood, causing the pressure in the atrium to exceed that in the empty ventricle
↓
The AV valve opens
Late diastole
There is a short period of time during which the left ventricle expands due to relaxing muscles
↓
This increases the internal volume of the left ventricle and decreases the ventricular pressure
↓
At the same time, blood is flowing slowly through the newly opened AV valve into the left ventricle, causing a brief decrease in pressure in the left atrium
↓
The pressure in both the atrium and ventricle then increases slowly as they continue to fill with blood
Question 5
Which is not a feature of the sinoatrial node (SAN)?
It acts as a natural pacemaker
It is formed from a group of highly specialised muscle cells
It occupies the area between the right atrium and the right ventricle
It sends out a wave of electrical activity, causing contraction, across both atria and both ventricles
