The heart

Question 1

The path of blood

Answer 1

• enters through the vena cava into the
  right atrium
• through the tricuspid valve into the right
  ventricle
• through the left pulmonary artery to the
  lungs
• back into the heart through the left
  pulmonary vein into the right atrium
• through the bicuspid valve into the left
  ventricle
• leaves through the semi lunar valve in the
  aorta to the rest of the body

Question 2

The cardiac cycle

Answer 2

• Atrial systole
• Ventricular systole
• Diastole

Question 3

Atrial systole

Answer 3

• atrium wall contracts so pressure
  increases
• atrium pressure greater then ventricle
  pressure so AV valve opens
• blood flows into the ventricles which is
  relaxed

Question 4

Ventricular systole

Answer 4

• ventricle wall contracts so pressure
  increases
• pressure now greater in the ventricle so
  AV valve close
• semi-lunar valve opens and blood flows
  through the pulmonary artery out of the
  heart

Question 5

Diastole

Answer 5

• ventricle relaxes increases the volume
  and decreasing pressure
• pressure in ventricle is lower than
  pulmonary artery so semi lunar valves
  close

Question 6

Valves

Answer 6

• prevents backflow of blood
• close under high blood pressure
• open under low blood pressure