B2.2 The Circulatory System

Question 1

What is the function of the circulatory system?

Answer 1

Transport substances around the body to the cells that need them

Question 2

What is the hollow cavity in the centre of blood vessels called?

Answer 2

The lumen

Question 3

state features of an artery (3)

Answer 3

thick outer wall (high pressure from heart)
thick layer of muscle + elastic fibres (to contract)
small lumen (maintain the pressure of blood from the heart )

Question 4

State the physical features of a vein (4)

Answer 4

thin outer wall
thin layer of muscle + elastic fibres
large lumen
valves (stop blood flowing wrong way)

Question 5

State features of capillaries (2)

Answer 5

small lumen (allows small diffusion distance)
Once cell thick (maximise diffusion through semipermeable walls)

Question 6

what is the function of arteries?

Answer 6

carry blood away from the heart

Question 7

what is the function of veins?

Answer 7

Return blood to the heart

Question 8

why do veins have valves? (2)

Answer 8

To prevent back flow
- since blood is flowing at low pressure, it is more likely to flow backwards

Question 9

What is the basic function of capillaries?

Answer 9

links arteries and veins in tissues + organs

Question 10

how do arteries work? (2)

Answer 10

muscle fibres contract to push blood forward
- then relax (and then the lumen expands)

Question 11

Why is it a double circulatory system? (3)

Answer 11

-Because blood passes through the heart twice per circuit.
-The right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart.
-The left pump sends the newly oxygenated blood around the body.

Question 12

Name two differences between oxygenated and deoxygenated blood:

Answer 12

-In oxygenated, the oxygen concentration is high whereas in deoxygenated, the concentration is low
-Oxygenated blood is bright red and deoxygenated is a dark red

Question 13

Compare double circulatory system and single circulatory system (2)

Answer 13

-In single circulation, blood travels once through the heart during a complete cycle
-In double circulation, blood flows twice through the heart during a complete cycle.

Question 14

What are the advantages of a double circulatory system?

Answer 14

-Provides a more efficient way of transporting oxygen and nutrients to the body.
-Allows for a greater volume of blood to be pumped with each heartbeat
-Which provides tissues with more oxygen and nutrients.