The Circulatory System And The Heart

Question 1

Circulatory system

Answer 1

A type of transport system made up of th heart, blood and vessels

Question 2

Transport system

Answer 2

A way of moving material around an organism in bulk

Question 3

Why do animals need a transport system
Explain the function of each component (5 marker)

Answer 3

Multicellular organisms need a transport system as most of their cells are far from the outside and have a small surface area to volume ratio
- Blood carries oxygen, haemoglobin, minerals, and nutrients and gets rid of carbon dioxide
- Blood vessels ensure blood is delivered and reduce the difference over which diffusion occurs
- The heart pumps blood around the body to maintain a diffusion gradient
Therefore, it would take too long for oxygen to difuse into cells and waste products to be removed by diffusion

Question 4

What are the two types of circulatory systems?

Answer 4

Single and double

Question 5

What is the single circulatory system?

Answer 5

Blood passes through the heart once for every complete circuit

Question 6

Organism that has a single circulatory system

Answer 6

Fish

Question 7

What is a double circulatory system

Answer 7

When blood passes through the heart twice for a complete circuit

Question 8

Organisms that have a double circulatory system

Answer 8

Mammals and birds

Question 9

The two circuits in the double circulatory system

Answer 9

• Systemic circuit
• Pulmonary circuit

Question 10

Function of systemic circuit (3 marker)

Answer 10

• Carries blood from the heart to the rest of the body and back to the heart again
• Oxygen diffuses out of blood to the tissues
• Carbon dioxide diffuses into the blood from the tissues

Question 11

Function of pulmonary circuit (3 marker)

Answer 11

• Carries blood from the heart to the lungs then back to the heart again
• Oxygen diffuses into blood at the lungs
• Carbon dioxide diffuses out of the blood at lungs

Question 12

Benefits of a double circulatory system (3 marker)

Answer 12

• More efficient
• Blood can be sent off to different parts of the body at a high pressure
• Oxygenated and deoxygenated blood do not mix together

Question 13

Why can’t active animals (like humans) not cope with a single circulatory system?

Answer 13

• Mammals have a much higher metabolic rate meaning they need oxygen delivered at a faster rate
• In a single circulatory system as there is a lower blood pressure to the tissues, oxygen wouldn’t be delivered to the cells at a fast enough rate

Question 14

Function of the atria (atrium=plural)

Answer 14

The top chamber where blood enters your heart and contracts to force blood into the ventricles

Question 15

Function of ventricles

Answer 15

Bottom chamber that contracts and forces blood out of the heart

Question 16

Valves

Answer 16

They close to stop blood from flowing backwards and out the heart

Question 17

Pacemaker

Answer 17

Regulates your heart rate

Question 18

What causes the sound of a heartbeat

Answer 18

Sound of the valves of the heart clossing to prevent the blood flowing backwards

Question 19

What happens if a pacemaker stops working properly?

Answer 19

Heart beat is too slow so not enough oxygen

Question 20

How can a pacemaker be treated if it is not working properly?

Answer 20

By using an artificial pacemaker

Question 21

Why is the muscle wall of the left ventricle thicker than the right ventricle?

Answer 21

The left side needs to be stronger so it can beat more forcefully