the heart

Question 1

name the 4 chambers of the heart

Answer 1

• left atrium
• right atrium
• left ventricle
• right ventricle

Question 2

What separates the left side of the heart to the right side?

Answer 2

septum

Question 3

What are the walls of the heart made of?

Answer 3

cardiac muscle

Question 4

What valves separate the atriums and ventricles, and what is their function?

Answer 4

• atrioventricular
• biscuspid = left
• tricuspid = right
  prevents backflow of blood

Question 5

What are the blood vessels on the outside of the heart called? What is their function?

Answer 5

coronary arteries
- deliver oxygenated blood to the heart walls as muscle near outside of the wall is too far away from blood inside ventricle to obtain oxygen from it.

Question 6

What is the cardiac cycle?

Answer 6

-The sequence of events which take place in the heart during one heart beat

Question 7

What happens in diastole in the cardiac cycle?

Answer 7

• muscles in the atria and ventricles are relaxed
• atria fill with blood
• as atrioventricular valves are open some of this blood passes into the ventricles
• semilunar valves in pulmonary artery and aorta are shut as blood pressure in ventricles is lower then the blood pressure in the arteries

Question 8

What happens in atrial systole in the cardiac cycle?

Answer 8

• the atria contract
• the ventricles are relaxed
• as the muscles in the atria walls contract, they squeeze inwards on the blood in the atria, raising its pressure and pushing it down through the atrio-ventricular valves, into the ventricles
• semilunar valves remain shut as blood pressure in ventricles is lower then blood pressure in the arteries

Question 9

What happens in ventricular systole in the cardiac cycle?

Answer 9

• the ventricles contract
• ventricle walls are thicker and stronger that in atria, so they can produce a much greater pressure. Blood is squeezed up into the aorta and pulmonary artery.
• pressure of the blood in the ventricles pushes upwards on the atria-ventricular valves, pushing them shut.

Question 10

suggest the consequences of a blockage in the coronary arteries (2 marks)

Answer 10

• oxygen cannot be transported around the body
• oxygen cannot reach the muscles
• risk of heart attack

Question 11

explain why the left ventricle is much thicker (3 marks)

Answer 11

• pumps blood around whole body so requires more force
• to push a large volume long distances which has greater resistance
• pulmonary circulation

Question 12

why is it important that the two sides of the heart are completely separated? (2 marks)

Answer 12

• oxygenated and deoxygenated blood don’t mix
• maintains different pressures
• oxygenated to body