B2- Organisation

Question 1

What is the heart?

Answer 1

An organ that pumps blood around the body

Question 2

What is the purpose of the circulatory system?

Answer 2

carries oxygen and other useful substances to bodily tissues, and removes waste substances

Question 3

How does the double circulatory system work?

Answer 3

• one pathway carries blood from the heart ti the lungs ( where the gaseous exchange of oxygen and carbon dioxide takes place)
• one pathway carries blood from the heart to the tissues

Question 4

why is the double circulatory system important?

Answer 4

It makes the circulatory system more efficient- for e.g, oxygenated blood can be pumped around the body at a higher pressure by the left ventricle

Question 5

How many chambers does the heart have and what are they called?

Answer 5

4- right atrium, right ventricle, left atrium, left ventricle

Question 6

Why is the wall of the left ventricle thicker?

Answer 6

the left ventricle has to pump blood at a higher pressure around the whole body

Question 7

What are the four main blood vessels associated with the heart?

Answer 7

• Aorta (left): carries oxygenated blood from the heart to the body
• Pulmonary vein (left): carries oxygenated blood from the lungs to the heart
• Vena cava ( right): carries deoxygenated blood from the body to the heart
• Pulmonary artery (right): carries deoxygenated blood from the heart to the lungs

Question 8

what is the purpose of valves in the heart?

Answer 8

prevent the backflow of blood

Question 9

What is the purpose of coronary arteries?

Answer 9

Coronary arteries supply the heart muscle with oxygenated blood

Question 10

Describe the process of blood flow through the heart

Answer 10

1) blood flows into the two atria from the vena cava and the pulmonary vein
2) the atria contract, pushing the blood into the ventricles
3) The ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart
4) the blood then flows to the organs through arteries, and returns through veins
5) The atria fill again and the whole cycle starts over

Question 11

what is the approximate value of the natural resting heart rate?

Answer 11

70 beats per minute

Question 12

How is the heart rate controlled?

Answer 12

Heart rate is controlled by a group of cells in the right atrium which act as a pacemaker. They release waves of electrical activity which cause the heart muscle to contract

Question 13

How can an abnormal heart rhythm be treated?

Answer 13

Irregular heart rhythms can be treated using an artificial pacemaker, which sends out electrical signals to correct the heart/s rhythm