Circulatory System and Exchange Surfaces B2

Question 1

What are exchange surfaces?

Answer 1

Exchange surfaces are specialised structures in the body that allow for the exchange of materials between the body and the environment (e.g. the alveoli in the lungs)

Question 2

Explain why exchanging substances is faster in unicellular organisms.

Answer 2

In unicellular organisms, substances only have to travel a short distance and they also have a relatively large surface area to volume ratio so transport rate is higher. However, in multi-cellular organisms the cell may be too deep inside the organism so it has to travel a longer way. Larger organisms also have a low surface area to volume ratio.

Question 3

What should an ideal efficient exchange system contain?

Answer 3

An efficient exchange should have a large surface area to volume ratio, membranes that are thin so diffusion distance is short and a good supply of transport (e.g. blood, air, etc.)

Question 4

What are some substances that need to be exchanged and transported?

Answer 4

Oxygen and carbon dioxide, dissolved food particles (e.g. glucose and minerals), urea (waste product from breakdown of protein) and water

Question 5

What is the role of the pulmonary artery?

Answer 5

The pulmonary artery carries deoxygenated blood from the heart to the lungs.

Question 6

What is the role of the aorta?

Answer 6

The aorta is the main artery that leaves the heart and supplies oxygenated blood to the body.

Question 7

What is the role of the pulmonary vein?

Answer 7

The pulmonary vein carries oxygenated blood from the lungs to the heart.

Question 8

What is the role of the vena cava?

Answer 8

The vena cava is formed by the body’s veins joining together and it carries deoxygenated blood back to the heart.

Question 9

What side of the circulatory system carries deoxygenated and oxygenated blood?

Answer 9

The right side of the circulatory system carries deoxygenated blood and the left side carries oxygenated blood.

Question 10

Which direction does blood with high levels of carbon dioxide and blood with high levels of oxygen travel?

Answer 10

Blood containing high levels of carbon dioxide returns to the heart and blood containing high levels of oxygenated flows to the cells in the body.

Question 11

What is the coronary artery and what does it do?

Answer 11

The coronary artery is an artery that provides the heart with the nutrients and oxygen that it needs.

Question 12

What three parts make up the circulatory system?

Answer 12

The heart, blood vessels and blood make up the circulatory system.

Question 13

What is the role of the circulatory system?

Answer 13

The circulatory system’s role is to transport nutrients and oxygen.

Question 14

What is the name of the top chamber in the heart?

Answer 14

The left and right atrium

Question 15

What is the name of the bottom chambers in the heart?

Answer 15

The left ventricle and right ventricle

Question 16

What is the role of valves?

Answer 16

Valves prevent blood from flowing backwards?

Question 17

Describe the cycle of movement of blood between the atria and ventricles.

Answer 17

The walls of the atria contract, pushing blood into the relaxed ventricles. The walls of the ventricles contract, pushing blood out of the heart. At the same time, more blood will enter the now-relaxed atria. The cycle repeats.

Question 18

What do pacemakers do?

Answer 18

Pacemakers send small electrical impulses to help the heart beat faster.

Question 19

Where are pacemakers found?

Answer 19

Pacemakers are found in the right atrium.

Question 20

What is the role of arteries?

Answer 20

Arteries carry blood away from the heart.

Question 21

What is the role of veins?

Answer 21

Veins carry blood towards the heart.

Question 22

What is the heart made from?

Answer 22

The heart is made from mostly muscles.