Transport in animals (B9.1)

What is the circulatory system?

• A group of organs for digestion.

• A system of blood vessels with a pump and valves.

• A network of nerves and muscles.

• A collection of bones and joints.

Answer explanation

The circulatory system consists of a network of blood vessels, a heart that pumps blood, and valves that regulate blood flow, making the correct choice 'A system of blood vessels with a pump and valves.'

Why does the circulatory system contain valves?

• To ensure one-way flow of blood.

• To store blood.

• To increase blood pressure.

• To decrease heart rate.

Answer explanation

The circulatory system contains valves to ensure one-way flow of blood, preventing backflow and maintaining efficient circulation throughout the body.

True or False? Fish have a single circulatory system.

• Only in saltwater fish

• False

• True

• Only in freshwater fish

Answer explanation

Fish have a single circulatory system, meaning their blood flows in one loop through the heart and body. This is true for all fish, regardless of whether they are saltwater or freshwater.

What is the benefit of double circulation in mammals?

• It decreases oxygen supply to cells.

• It increases the size of the heart.

• It reduces the number of heartbeats.

• It allows the heart to pump blood at high pressure.

Answer explanation

Double circulation in mammals allows the heart to pump oxygenated blood at high pressure to the body, ensuring efficient delivery of oxygen and nutrients to cells, which is crucial for their proper functioning.

Which structure in the heart is labeled as 'A'?

• Right atrium

• Right ventricle

• Left ventricle

• Left atrium

Answer explanation

The right atrium is the upper chamber of the heart that receives deoxygenated blood from the body. It is labeled as 'A' in the diagram, distinguishing it from the other chambers.

How does blood return to the heart from the lungs?

• Via the pulmonary artery

• Via the vena cava

• Via the pulmonary vein

• Via the aorta

Answer explanation

Blood returns to the heart from the lungs via the pulmonary vein. This vessel carries oxygenated blood from the lungs to the left atrium of the heart, distinguishing it from the pulmonary artery, which carries deoxygenated blood away from the heart.

Which vein is the only vein in the body to carry oxygenated blood?

• Renal vein

• Vena cava

• Coronary vein

• Pulmonary vein

Answer explanation

The pulmonary vein is unique as it carries oxygenated blood from the lungs to the heart, unlike other veins which carry deoxygenated blood. This makes it the only vein in the body to transport oxygen-rich blood.

True or False? Arteries carry blood away from the heart.

• False

• True

• Only in mammals

• Only in fish

Answer explanation

True. Arteries are blood vessels that carry blood away from the heart to various parts of the body, regardless of the type of organism.

What is coronary heart disease (CHD)?

• A condition where the blood becomes too thick.

• A condition where the heart grows larger.

• A condition where the heart stops beating.

• A condition where the coronary arteries narrow due to fatty deposits.

Answer explanation

Coronary heart disease (CHD) occurs when the coronary arteries narrow due to fatty deposits, leading to reduced blood flow to the heart. This is the correct definition, unlike the other options which describe different conditions.

What are the two types of valve labeled X and Y?

• X = bicuspid valve, Y = tricuspid valve

• X = pulmonary valve, Y = mitral valve

• X = semilunar valve, Y = atrioventricular valve

• X = mitral valve, Y = aortic valve

Answer explanation

The correct answer identifies X as a semilunar valve and Y as an atrioventricular valve. Semilunar valves include the aortic and pulmonary valves, while atrioventricular valves include the mitral and tricuspid valves.